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1Back to top Go down   Tuning My K100 Empty Tuning My K100 on Tue Feb 05, 2019 5:35 pm

DBRMN

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Now, I've been reading up on tuning TBs and have found a few posts that hold your hand through the process, linked below;
http://www.k100-forum.com/t1526-how-to-balance-the-throttle-bodies-solved
http://www.k100-forum.com/t3880-what-is-the-correct-procedure-for-synching-throttle-bodies-on-91-k100rs-4v
http://www.k100-forum.com/t5671-16valve-throttle-body-sync
http://www.k100-forum.com/t8259-tune-up-and-adjustments

However my question is, if I have modified the exhaust (pretty much straight piped) and half the air intake system, can describe in more detail if needed, then will adjusting the air-fuel mixture rectify this? As from when I tried to run the bike without an exhaust, the lack of back pressure prevented it from even idling, so is this even a problem I can fixed with tuning or is a much more thorough tune needed?

Simple question being how much tuning can you do on the TBs?

Thanks,
DBRMN

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2Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Tue Feb 05, 2019 11:39 pm

Point-Seven-five

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Not sure how to do it on a fuel injected engine.

In days past we tuned with plug readings and timed test runs, changing carburetor jets, ignition timing, and spark plugs.


__________________________________________________
Present:
1994 K75RT
1991 K100RS

Past:
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

3Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 1:16 am

MartinW

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First check and adjust the valves, and check the compression and spark plugs. All the 2v Bricks have a built in check system to check your mixture. With the idle set to run at 1000 RPM press the green starter button. The revs should either rise slightly or stay the same, if it rises significantly or the engine dies the mixture needs adjusting. This is done with a 5mm Allen key through a rubber plug covered hole in the RH top corner of the airbox. This can be done by either using an exhaust gas analyser or the lean drop method. The balance between the throttle bodies can be checked with either an off the shelf 4 gauge manometer or home made version. I've never had to adjust the timing. Never play with the throttle body screws covered with the blue paint.
Regards Martin.


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4Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 3:25 am

chris846

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With the airbox & exhaust mods you've got, you should still be able to get the bike to run just fine with everything as standard. That's what you should aim for to start with - if it isn't running properly don't rush into thinking you need to 'tune' it to cope with your mods. It's much more likely to be a 'normal' problem that a K can encounter. This approach (and the guys on this forum, naturally) will help you troubleshoot anything you come across.

Once you've got it running 'normal', then you can explore the various tweaks.

Easy does it eh?

(And then we'll talk about swapping your crank for a lighter one - 1.2Kg makes a lovely difference!)

Tuning My K100 00411


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5Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 6:38 am

92KK 84WW Olaf

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And don't forget about swapping in K75 pistons...raises compression ratio, K75 has higher compression and outputs 100 bhp/litre, K100 outputs 90 bhp/litre.

Also double check your lack of idle isn't due to issues with damaged Z pipe vent, vacuum caps or vacuum pipes leaking/missing etc.


__________________________________________________
1992 K100LT 0193214 Bertha Alaska Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 58,645 now91,850 miles
1983 K100RS 0011175 Fricka 29,495 miles Damn K Pox
    

6Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 7:30 am

DBRMN

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@Point-Seven-five wrote:Not sure how to do it on a fuel injected engine.

In days past we tuned with plug readings and timed test runs, changing carburetor jets, ignition timing, and spark plugs.
I think you'd find the threads I mentioned quite interesting then.

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7Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 12:26 pm

DBRMN

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@chris846 wrote:With the airbox & exhaust mods you've got, you should still be able to get the bike to run just fine with everything as standard. That's what you should aim for to start with - if it isn't running properly don't rush into thinking you need to 'tune' it to cope with your mods. It's much more likely to be a 'normal' problem that a K can encounter. This approach (and the guys on this forum, naturally) will help you troubleshoot anything you come across.

Once you've got it running 'normal', then you can explore the various tweaks.

Easy does it eh?

(And then we'll talk about swapping your crank for a lighter one - 1.2Kg makes a lovely difference!)

Tuning My K100 00411
What do you mean without tuning? What would you be changing if you weren't changing the TB air fuel mixture, TBS etc? To get it to idle well.

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8Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 12:27 pm

DBRMN

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@MartinW wrote: First check and adjust the valves, and check the compression and spark plugs. All the 2v Bricks have a built in check system to check your mixture. With the idle set to run at 1000 RPM press the green starter button. The revs should either rise slightly or stay the same, if it rises significantly or the engine dies the mixture needs adjusting. This is done with a 5mm Allen key through a rubber plug covered hole in the RH top corner of the airbox. This can be done by either using an exhaust gas analyser or the lean drop method. The balance between the throttle bodies can be checked with either an off the shelf 4 gauge manometer or home made version. I've never had to adjust the timing. Never play with the throttle body screws covered with the blue paint.
Regards Martin.
Which air box is that the left hand side or the right hand side, because the right hand side I have removed and replaced with a pod filter.

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9Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 12:54 pm

92KK 84WW Olaf

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If you have removed the right hand side box haveyou have also removed the air flow meter [MAF]??

Have you swapped out the original K Bosch system [Jetronic LE]?

Its outside my area of knowledge but as far as I know you can't have one without the other.


__________________________________________________
1992 K100LT 0193214 Bertha Alaska Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 58,645 now91,850 miles
1983 K100RS 0011175 Fricka 29,495 miles Damn K Pox
    

10Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 1:05 pm

MartinW

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You should find the adjustment screw for 5mm Allen key on the top RH corner of the MAF.
Regards Martin.


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K75s Hybrid
    

11Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 2:41 pm

chris846

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Ref. post 7, we could be at crossed purposes, if the bike won't idle then I'd be looking at such things as the breather pipe leak already mentioned, or leaks around the rubber throttle body/cylinder adaptors if they've been removed and replaced during the rebuild - they go hard and in my experience they won't seal without RTV where they mate to the cylinder head. I wouldn't be twiddling the AFM bypass screw until I knew that everything else was okay - there'd be no point and you'd just be adding to the list of 'things-I've-disturbed'. Likewise the brass bypass screws in the throttle bodies, although you can use these to fault find: with the engine running on a closed throttle, carefully wind them in (counting the turns!) and then back out again. If this doesn't alter the tickover, then you've got an air leak - either the rubber adaptor, or the throttle plate (somebody's been at the blue-painted screws!).


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12Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 4:36 pm

DBRMN

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@92KK 84WW Olaf wrote:If you have removed the right hand side box haveyou have also removed the air flow meter [MAF]??

Have you swapped out the original K Bosch system [Jetronic LE]?

Its outside my area of knowledge but as far as I know you can't have one without the other.
Tuning My K100 Img_2325
Sorry should of attached a photo this is my current set up, it should be air tight. But the Pod filter mounts straight to the AFM, it won't stick out that much this is just a prototype.

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13Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 4:42 pm

DBRMN

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@chris846 wrote:Ref. post 7, we could be at crossed purposes, if the bike won't idle then I'd be looking at such things as the breather pipe leak already mentioned, or leaks around the rubber throttle body/cylinder adaptors if they've been removed and replaced during the rebuild - they go hard and in my experience they won't seal without RTV where they mate to the cylinder head. I wouldn't be twiddling the AFM bypass screw until I knew that everything else was okay - there'd be no point and you'd just be adding to the list of 'things-I've-disturbed'. Likewise the brass bypass screws in the throttle bodies, although you can use these to fault find: with the engine running on a closed throttle, carefully wind them in (counting the turns!) and then back out again. If this doesn't alter the tickover, then you've got an air leak - either the rubber adaptor, or the throttle plate (somebody's been at the blue-painted screws!).
Ye I think we were my fault, I've recently replaced the Z breather pipe as I noticed it was cracked. However before the modifications my bike ran perfectly fine. I haven't tried to start the bike since the modifications, however I anticipate back pressure problems and possibly an unbalanced air-fuel mixture due to either too much or too little air flow. I plan on testing for leaks in the air intake system as a hole with that starter spray thing, hope u know what i mean. Then the second part of my plan is to do what you've mentioned about the brass bypass screw adjustments. However what I started this thread for is my fear that I won't even get it to idle, due to lack of back pressure and wrong air-fuel mixture. What do you think?

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14Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 4:43 pm

DBRMN

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@MartinW wrote:You should find the adjustment screw for 5mm Allen key on the top RH corner of the MAF.
Regards Martin.
What does adjusting this do to the internals? Whats it's effect?

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15Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 5:16 pm

chris846

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I modified a K100 similarly to you - binned the air filter housing (the 'right-hand box') and left the AFM out in the breeze with a cone filter stuck on its end. My exhaust was the standard headers into a collector and a straight through silencer. Your bike should run and tickover just fine with similar mods without having to tweak the AFM/brass bypass screws/anything else.

Yes, you might have some room for fine-tuning the AFM to get an ideal mixture at tickover, but it should still run and tickover with the setting it was previously on.

The adjustment screw in the AFM is a simple bypass/bleed screw - it allows a small amount of air to bypass the flapper vane, which turns the potentiometer and informs the ECU how much fuel to inject. The flapper vane itself still opens on tickover and allows metered air into the engine - so opening(unscrewing) the bypass screw just adds unmetered air to the mix and so weakens the mixture. It is a very minor effect, only noticeable at tickover and just off tickover. Once the throttles are open and the engine is drawing in two thousand revs worth of air, the small amount of unmetered air flowing via the AFM bypass screw is immaterial in comparison.

The brass screws on the throttle bodies work in a similar way - they allow a small amount of air to bypass the throttle plates. This is what allows the bike to breathe enough to tickover, when the throttles are closed. The brass bypass screws are important because, with the best engineering in the world, the throttle plates leak a tiny amount of mixture, each by differing amounts. Bear in mind that a throttle is just that - when that engine is ticking over you are strangling it almost to death - it's sucking air in from wherever it can get it. The brass screws are used to balance the air flows in the individual throttles, which is necessary for an even tickover. Their effect is lost almost as soon as the throttles are open, even a small amount.

The blue-painted link screws between the throttles are a very different story - they keep the throttles flowing even amounts of mixture up to around 1/3 throttle, after that, their effect diminishes. They have the biggest effect on clean, smooth running at part throttle.

If the blue-painted screws have been twiddled, then it's likely that (aside from messing up the the part-throttle balance) this has caused one or more of the throttle plates to remain fractionally open when the others are closed. In this case the brass bypass screw for that throttle will have no effect whatsoever. This can be a world of pain, although it is possible to recover things with a 4-way carbtune or similar (the sorry sound of experience huh?)

Hope that helps.



Last edited by chris846 on Wed Feb 06, 2019 5:41 pm; edited 2 times in total


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16Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 5:22 pm

DBRMN

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@chris846 wrote:I modified a K100 similarly to you - binned the air filter housing (the 'right-hand box') and left the AFM out in the breeze with a cone filter stuck on its end. My exhaust was the standard headers into a collector and a straight through silencer. Your bike should run and tickover just fine with similar mods.

Yes, you might have some room for fine-tuning the AFM to get an ideal mixture at tickover, but it should still run and tickover with the setting it was previously on.

The adjustment screw in the AFM is a simple bypass/bleed screw - it allows a small amount of air to bypass the flapper vane, which turns the potentiometer and informs the ECU how much fuel to inject. The flapper vane itself still opens on tickover and allows metered air into the engine - so opening(unscrewing) the bypass screw just adds unmetered air to the mix and so weakens the mixture. It is a very minor effect, only noticeable at tickover and just off tickover. Once the throttles are open and the engine is drawing in two thousand revs worth of air, the small amount of unmetered air flowing via the AFM bypass screw is immaterial in comparison.

The brass screws on the throttle bodies work in a similar way - they allow a small amount of air to bypass the throttle plates. This is what allows the bike to breathe enough to tickover, when the throttles are closed. The brass bypass screws are important because, with the best engineering in the world, the throttle plates leak a tiny amount of mixture, each by differing amounts. Bear in mind that a throttle is just that - when that engine is ticking over you are strangling it almost to death - it's sucking air in from wherever it can get it. The brass screws are used to balance the air flows in the individual throttles, which is necessary for an even tickover. Their effect is lost almost as soon as the throttles are open, even a small amount.

The blue-painted link screws between the throttles are a very different story - they keep the throttles flowing even amounts of mixture up to around 1/3 throttle, after that, their effect diminishes. They have the biggest effect on clean, smooth running at part throttle.

Hope that helps.
How effective was your aftermarket silencer, as the set up I have at the moment is 4-to-1 collector followed by a cheap Chinese silencer, which is pretty much a straight pipe. Below is a video of when I tried starting the bike without the stock silencer, this is what I fear for when I try and start it now;


You can clearly hear it running on two maybe three of its cylinders and refuses to idle.

Yeah what your saying about the bypass screws and the AFM adjuster makes me think it would have a big enough effect to rectify this^^.

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17Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 5:34 pm

chris846

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I was trying to say the opposite - I don't think your exhaust is the reason for it running on two/three cylinders.

Check sparks.

Check injectors - whip the fuel rail off and position the nozzles to squirt onto kitchen roll. Hit the starter for a couple of cranks and the damp circles should be the same size - remember you are playing with petrol!

If okay, see if it starts to run more evenly as you crack open the throttle. This could indicate an air leak.

- I'm assuming that you haven't altered the bypass screws from prior to the rebuild?


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18Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 5:39 pm

DBRMN

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@chris846 wrote:I was trying to say the opposite - I don't think your exhaust is the reason for it running on two/three cylinders.

Check sparks.

Check injectors - whip the fuel rail off and position the nozzles to squirt onto kitchen roll. Hit the starter for a couple of cranks and the damp circles should be the same size - remember you are playing with petrol!

If okay, see if it starts to run more evenly as you crack open the throttle. This could indicate an air leak.

- I'm assuming that you haven't altered the bypass screws from prior to the rebuild?
You see I thought these things but here's a video of it a week later with the original exhaust back on;



and here it just purs beautifully, It might of had a small air leak, due to the Z breather hose I mentioned (both these videos are pre-replacement)

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19Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 5:46 pm

chris846

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That seems to make a case for it being the exhaust, but my own experience says otherwise. Maybe try back to back exhaust swaps - that should be fairly easy?


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20Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 5:48 pm

DBRMN

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@chris846 wrote:That seems to make a case for it being the exhaust, but my own experience says otherwise. Maybe try back to back exhaust swaps - that should be fairly easy?
I have to admit I've been very lucky with the starting bike, it was very low mileage and looked after like a god. I've heard if you run the bike for a while on the stock exhaust it should cope being straight piped.

Do you have any idea how to prep the fuel air mixture to accommodate for this? Does it just need to run a bit richer?

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21Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 6:00 pm

chris846

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The AFM bypass screw and the brass bypass screws have nowhere near enough effect to richen the mixture throughout the range. There's postings about resetting the potentiometer inside the AFM, and another way is to overpressure the fuel delivery with an adjustable FPR. I've done both, but I do have a wideband Lambda and gauge fitted so's I can see what's happening.

I still run the bike on standard settings.

If I were in your garage now, having done what you've already done with swapping back to the standard can, I'd still do a straight back to back swap to convince myself.


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22Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 6:02 pm

MartinW

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What happens when you press the green start button with it idling at 1000 RPM. What do the plugs look like.
Regards Martin.


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23Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 6:20 pm

DBRMN

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@chris846 wrote:The AFM bypass screw and the brass bypass screws have nowhere near enough effect to richen the mixture throughout the range. There's postings about resetting the potentiometer inside the AFM, and another way is to overpressure the fuel delivery with an adjustable FPR. I've done both, but I do have a wideband Lambda and gauge fitted so's I can see what's happening.

I still run the bike on standard settings.

If I were in your garage now, having done what you've already done with swapping back to the standard can, I'd still do a straight back to back swap to convince myself.
That sounds like it's going to get a lot more complicated. If it is a question of simply a lack of back pressure I've heard that some wire wool shoved in the silencer would create a bit of back pressure, so I'm going to try it when I get round to starting it.

Your talking bout a side by side comparison aren't you, yeah I think thats a good idea. It would never hurt to try the old exhaust as a control variable.

I'm currently waiting till I finish my coolant overflow tank, cause the bike doesn't have coolant in at the moment. But straight after that is this, so I thought I'd get my research in early.

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24Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 6:25 pm

DBRMN

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@MartinW wrote:What happens when you press the green start button with it idling at 1000 RPM. What do the plugs look like.
Regards Martin.
I currently can't test that due to the coolant not in yet, what would you be expecting from this. I have however looked at my plugs recently and they looked good, and definitely all providing a good spark.

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25Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 6:27 pm

MartinW

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Read post #3.
Regards Martin.


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26Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 6:29 pm

DBRMN

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@MartinW wrote:Read post #3.
Regards Martin.
Ah yes, so is the idle automatically set at 1000rpm? how do you change the idle, is it the adjustment screw on the TBs at the front? And what are you actually doing by pressing the green starter button again, like electronically?

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27Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 6:44 pm

MartinW

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For the test to work the idle has to be set at 1000RPM or over or the starter motor will engage. The green button once over 1000RPM enriches the mixture. The 5mm screw adjusts the mixture. When pressed the revs should stay the same or rise very slightly.
Regards Martin.


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28Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 6:46 pm

DBRMN

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@MartinW wrote:For the test to work the idle has to be set at 1000RPM or over or the starter motor will engage. The green button once over 1000RPM enriches the mixture. The 5mm screw adjusts the mixture. When pressed the revs should stay the same or rise very slightly.
Regards Martin.
So how does one set the idle?

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29Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 7:17 pm

RicK G

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@MartinW wrote:For the test to work the idle has to be set at 1000RPM or over or the starter motor will engage. The green button once over 1000RPM enriches the mixture. The 5mm screw adjusts the mixture. When pressed the revs should stay the same or rise very slightly.
Regards Martin.
To make things quite clear here it is actually 711RPM when the ICU prevents the starter motor turning by removing the earth from the start relay.
The enrichment is controlled by the ECU and will enrich the mixture for ease of starting while the button is pressed.


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"Every normal man must be tempted, at times, to spit upon his hands, hoist the black flag, and begin slitting throats." from Mencken's 1919 Prejudices

Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

30Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Wed Feb 06, 2019 7:20 pm

MartinW

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First thing you should buy or download is a manual. These are available on this site on the download page. The idle adjustment screw is approximately in the middle of the throttle body linkages near the throttle cable. But if you check the available and downloadable manual on site it will clarify your situation. Warning unless you like headaches don't mess with the screws with the blue paint on them.
Regards Martin.


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31Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Thu Feb 07, 2019 3:24 pm

DBRMN

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@RicK G wrote:
@MartinW wrote:For the test to work the idle has to be set at 1000RPM or over or the starter motor will engage. The green button once over 1000RPM enriches the mixture. The 5mm screw adjusts the mixture. When pressed the revs should stay the same or rise very slightly.
Regards Martin.
To make things quite clear here it is actually 711RPM when the ICU prevents the starter motor turning by removing the earth from the start relay.
The enrichment is controlled by the ECU and will enrich the mixture for ease of starting while the button is pressed.
Could you go into a bit more detail? I'm not sure I fully understand and it sounds interesting.

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32Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Thu Feb 07, 2019 3:25 pm

DBRMN

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@MartinW wrote:First thing you should buy or download is a manual. These are available on this site on the download page. The idle adjustment screw is approximately in the middle of the throttle body linkages near the throttle cable. But if you check the available and downloadable manual on site it will clarify your situation. Warning unless you like headaches don't mess with the screws with the blue paint on them.
Regards Martin.
Got my Haynes manual, I always find it helpful but not as helpful as peoples first hand experience. Yeah the biggest thing I've read is just don't mess with the blue painted screws, just the brass ones. I say a helpful diagram that someone attached in another thread, I'll see if I can find it.

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33Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Thu Feb 07, 2019 3:27 pm

DBRMN

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Here we go, posted by Crazy Frog. Its of a K75, but similar deal.

Tuning My K100 Thrott10

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34Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Thu Feb 07, 2019 5:01 pm

glennpm

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@DBRMN wrote:
You won't have much luck with the wool. Putting a washer in the end of the pipe would be much better and you can tune it by rotating the angle. IMHO your bike will run better with more torque if you have back pressure

https://www.tabperformance.com/Reduce-Back-Pressure-Exhaust-s/203.htm

Glenn
That sounds like it's going to get a lot more complicated. If it is a question of simply a lack of back pressure I've heard that some wire wool shoved in the silencer would create a bit of back pressure, so I'm going to try it when I get round to starting it.

Your talking bout a side by side comparison aren't you, yeah I think thats a good idea. It would never hurt to try the old exhaust as a control variable.

I'm currently waiting till I finish my coolant overflow tank, cause the bike doesn't have coolant in at the moment. But straight after that is this, so I thought I'd get my research in early.

    

35Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Thu Feb 07, 2019 5:38 pm

Point-Seven-five

Point-Seven-five
Life time member
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My experience with steel wool is that it gets blown out in the first 2-3 miles.


__________________________________________________
Present:
1994 K75RT
1991 K100RS

Past:
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

36Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Thu Feb 07, 2019 6:40 pm

DBRMN

DBRMN
Life time member
Life time member
@glennpm wrote:
@DBRMN wrote:
You won't have much luck with the wool. Putting a washer in the end of the pipe would be much better and you can tune it by rotating the angle. IMHO your bike will run better with more torque if you have back pressure

https://www.tabperformance.com/Reduce-Back-Pressure-Exhaust-s/203.htm

Glenn
That sounds like it's going to get a lot more complicated. If it is a question of simply a lack of back pressure I've heard that some wire wool shoved in the silencer would create a bit of back pressure, so I'm going to try it when I get round to starting it.

Your talking bout a side by side comparison aren't you, yeah I think thats a good idea. It would never hurt to try the old exhaust as a control variable.

I'm currently waiting till I finish my coolant overflow tank, cause the bike doesn't have coolant in at the moment. But straight after that is this, so I thought I'd get my research in early.
I have actually heard of that before the only thing stopping me is my four into one collector cost 250 so if I don't like it or want it out, i then have a hole in my collector lol

https://www.gofundme.com/manage/helping-fund-my-motorbike-projec
    

37Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Thu Feb 07, 2019 6:40 pm

DBRMN

DBRMN
Life time member
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@Point-Seven-five wrote:My experience with steel wool is that it gets blown out in the first 2-3 miles.
really? how much did you put in? how dense etc.

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38Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Thu Feb 07, 2019 7:09 pm

glennpm

glennpm
Silver member
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It will just blow out, BTDT when trying to pass inspection in an old Ford MANY years ago. I put it in bikes to keep mice out in winter. If I forget in Spring it just blows out. ;-)

    

39Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Thu Feb 07, 2019 9:54 pm

Point-Seven-five

Point-Seven-five
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@DBRMN wrote:
@Point-Seven-five wrote:My experience with steel wool is that it gets blown out in the first 2-3 miles.
really? how much did you put in? how dense etc.
It was a long time ago. I had modified a muffler by packing it with coarse steel wool in an attempt to meet the sound requirement of the ISDT rules at a 2 day qualifier. I managed to pass the morning sound check when i pulled out of the impound area, but I was about a couple hundred yards from the start line when the last of it disappeared.

Al Eames, who was the head judge, was not amused. That "trick" cost me a bronze medal.

Maybe you should tell us where you heard that steel wool worked in exhaust systems.


__________________________________________________
Present:
1994 K75RT
1991 K100RS

Past:
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

40Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Fri Feb 08, 2019 1:14 am

Two Wheels Better

Two Wheels Better
Moderator
Moderator
@DBRMN wrote:
@Point-Seven-five wrote:My experience with steel wool is that it gets blown out in the first 2-3 miles.
really? how much did you put in? how dense etc.
Want to see how to repack a repackable zorst? Go here and look at post number 58, on the second page.
Repacking zorst


__________________________________________________

1987 K100RS, '89 K100 w/K1100RS engine, '93 Framed K11/K12 engine 'Big Block', '96 K1100RS, '09 K1300GT, '07 K1200R, '95 R100 Mystic & '77 R75/7.

    

41Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Fri Feb 08, 2019 3:39 am

chris846

chris846
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You might be getting confused with 'normal' exhaust packing/wadding. This is where the gases pass along a perforated tube, and a chamber - the silencer - is created around the tube for the sound/pressure waves to expand into through the perforations and lose their energy before they emerge at the end of exhaust. The chamber is packed with material (usually fibreglass) to deaden the sound. The exhaust gases do not flow through the packing. This type of silencer is called a 'straight through' and is the most common type of aftermarket silencer.

In my younger days, when I knew even less than I do now, I built my own silencer with a central chamber packed with fibreglass wadding. The exhaust gases had to force their way through the wadding. Surely that's how these things work huh?

I started the engine up and revved the mutha, within seconds the garage was completely filled with glittering fibreglass particles. There was nothing left in the exhaust.

Some of my learning curves have been so steep, I should have been a mountaineer. Sounds like point-seven-five was maybe on the same rope with me on occasion too.

That's what will happen if you stuff steel wool into your straight through exhaust.

(and it won't cure the misfire either!)


__________________________________________________
The Longest Lunch
    

42Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Fri Feb 08, 2019 8:21 am

glennpm

glennpm
Silver member
Silver member
Hi,

I had another idea this morning for a temporary baffle for testing that wouldn't require drilling a hole.

Take a piece of sheet metal and cut a strip about equal to half the exhaust pipe outlet diameter. The strip should perhaps be about 75 to 100mm long. Bend this in the middle of the 75mm to make a V shape. The open part of the V should be greater than the exhaust outlet and the gauge of the sheet metal stiff enough so the V bend will not bend with finger force. The legs of the V should be inserted into the pipe and if your angle of the V is not too large or too small, pushing into the ID of the pipe will hold it in place. Push it in so the V is close to the end or sticking out a little bit.

I was going to add about silencer packing and how it works but Chris846 just did it well.

Glenn



Last edited by glennpm on Fri Feb 08, 2019 4:06 pm; edited 2 times in total (Reason for editing : verbage)

    

43Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Fri Feb 08, 2019 5:59 pm

MartinW

MartinW
Life time member
Life time member
Way back in the dark ages, I had a home made mini bike. Single cylinder two stroke. two exhausts Jawa. The exhausts consisted of drilling multiple holes in the header pipes the mufflers consisted of large pineapple juice cans that were packed with stainless steel wool and slid over the header pipe and hose clamped on at both ends. They worked reasonable well but they didn't seal that well at both ends of the tins. I had the bike for over a year and never had to repack the mufflers.
Regards Martin.


__________________________________________________
K75s Hybrid
    

44Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Fri Feb 08, 2019 8:18 pm

Point-Seven-five

Point-Seven-five
Life time member
Life time member
As I recall, my attempt was to hose clamp a couple U-shaped pieces of coat hanger across the end of the exhaust pipe where my pie pan Super Trapp muffler was the day before(The back pressure of a deep water crossing blew the damn thing off the day before). The idea was to have the cross formed by the coat hanger wire hold the steel wool in the exhaust pipe. With only fifteen minutes in the impound area to do all my maintenance for the upcoming day, I didn't have the time to get more elegant.


__________________________________________________
Present:
1994 K75RT
1991 K100RS

Past:
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

45Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Sat Feb 09, 2019 9:33 am

DBRMN

DBRMN
Life time member
Life time member
So the wire wool is clearly not an option, I'd only heard it as a suggestion/theory.

So I'm going to have to consider this washer design I think.

https://www.gofundme.com/manage/helping-fund-my-motorbike-projec
    

46Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Sat Feb 09, 2019 9:33 am

DBRMN

DBRMN
Life time member
Life time member
@glennpm wrote:Hi,

I had another idea this morning for a temporary baffle for testing that wouldn't require drilling a hole.

Take a piece of sheet metal and cut a strip about equal to half the exhaust pipe outlet diameter. The strip should perhaps be about 75 to 100mm long. Bend this in the middle of the 75mm to make a V shape. The open part of the V should be greater than the exhaust outlet and the gauge of the sheet metal stiff enough so the V bend will not bend with finger force. The legs of the V should be inserted into the pipe and if your angle of the V is not too large or too small, pushing into the ID of the pipe will hold it in place. Push it in so the V is close to the end or sticking out a little bit.

I was going to add about silencer packing and how it works but Chris846 just did it well.

Glenn
I like the sound of this temporary design for testing, could you draw a diagram or something because I won't lie I can't visualise what you mean?

https://www.gofundme.com/manage/helping-fund-my-motorbike-projec
    

47Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Sat Feb 09, 2019 11:26 am

glennpm

glennpm
Silver member
Silver member
Tuning My K100 Dscn0630
Sure, quick pattern made out of cardboard. Make the open end of the V large enough so when you slip it in the pipe, it has some grip on the inside.

Tuning My K100 Dscn0628
Tuning My K100 Dscn0627
Tuning My K100 Dscn0629

    

48Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Sat Feb 09, 2019 11:30 am

DBRMN

DBRMN
Life time member
Life time member
@glennpm wrote:Tuning My K100 Dscn0630
Sure, quick pattern made out of cardboard. Make the open end of the V large enough so when you slip it in the pipe, it has some grip on the inside.

Tuning My K100 Dscn0628
Tuning My K100 Dscn0627
Tuning My K100 Dscn0629
Ah wow yes I see that, very clever so what would you recommend, some 1.5mm gauge ali or could you get away with 1mm.

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49Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Sat Feb 09, 2019 11:33 am

glennpm

glennpm
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Silver member
Good!

I think the 1mm would work. If it bends too easy when you go to insert it, you'll know that you'll have to go with 1.5mm instead and certainly no thicker than that.

    

50Back to top Go down   Tuning My K100 Empty Re: Tuning My K100 on Sat Feb 09, 2019 11:39 am

DBRMN

DBRMN
Life time member
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@glennpm wrote:Good!

I think the 1mm would work. If it bends too easy when you go to insert it, you'll know that you'll have to go with 1.5mm instead and certainly no thicker than that.
I'm definitely going to try this thank you so much for your help, and everyone else.

I think whats going to happen from here is I'm going to leave this thread till I'm actually trying to start the bike up, then I'll updated this thread daily as I start actually physically troubleshooting, thank you all so much for the information its going to make this a lot easier I think.

https://www.gofundme.com/manage/helping-fund-my-motorbike-projec
    

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