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1Back to top Go down    K1100 Throttle Bodies On A K75 on Sun Apr 27, 2014 2:51 pm

duck

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Linky:http://classickbikes.com/ckb.tech/0.ckb.tech.files/k11tbk75/k11tbk75.htm


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Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S
14 Yamaha WR250R
http://www.ClassicKBikes.com
    

2Back to top Go down    Re: K1100 Throttle Bodies On A K75 on Sun Apr 27, 2014 3:26 pm

Two Wheels Better

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This is what we like. I'm interested to hear how the installation and end result goes. I reckon the quite under-stressed K75 motors have a fair bit of extra hidden within which mods like this tap into.

Thanks for the link.


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'77 R75/7-1000cc, '87 K100RS, '93 K11/K12 Big Block, '94 R100R Mystic, '03 K1200GT, '04 R1150RT, '06 K1200R, '07 K1200R & 2009 K1300GT
    

3Back to top Go down    Re: K1100 Throttle Bodies On A K75 on Sun Apr 27, 2014 9:09 pm

orforester

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Duck you are always coming up with creative ideas.

I am still awaiting my starter brushes, they must have to be made in Germany then shipped over or something like that, then I can try to start my RS, now RT!


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89 K 100 RS se
85 K 100 RT
    

4Back to top Go down    Re: K1100 Throttle Bodies On A K75 on Sun Apr 27, 2014 10:12 pm

duck

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Creative ideas? All I did was copy what somebody else had done.

The last creative thought I had was in 1972.


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Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S
14 Yamaha WR250R
http://www.ClassicKBikes.com
    

5Back to top Go down    Re: K1100 Throttle Bodies On A K75 on Sun Apr 27, 2014 11:02 pm

RicK G

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I have been thinking of doing that and putting a motronic on it.


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If everything seems under control then you aint goin fast enough:- Mario Andretti
Bikes 1986 K100RT, 1993 K1100 LT, 1994 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 & 1976 SR 500 Yamaha for now
    

6Back to top Go down    Re: K1100 Throttle Bodies On A K75 on Sun May 04, 2014 2:33 pm

robmack

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I fired up the K75 todayafter completing my customization, first time in 1.5 years. I fitted some K1100 TBs as part of the customization.Read about the installation of these on my blog

The motor started but ran roughly for a K75. I put the Carbtune on the TBs and sure enough, the TB sync is out of whack. Cylinder 1 is pulling about 34 cmHg, Cylinder 2 about 24 cmHg but Cylinder 3 is zero cmHg.

I'm not sure what to make of this. Here's what's been done:

  • K1100 TB put in place of the K75's.
  • all air bypass screws reset to 1.5 turns out
  • TB bushings between engine and TB and TB, and air plenum were all checked for deterioration; they appear in good condition.
  • brand new rubber caps sealing off the balance tube inputs at the back of the TBs
  • RTV used between TB bushings and intake manifolds to seal
  • "Z" tube between air plenum and engine is brand new; no cracks or splits.

Can anyone suggest why the Cylinder 3 TB doesn't pull any vacuum? This was the TB that I replaced the pivot shaft so there is the possibility that the butterfly valve is maladjusted but I wouldn't expect zero vacuum.

I think that the only cause of this is air leakage but where? I'll try the propane trick to confirm this. Should this be my next troubleshooting step or something else?


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Robert
1987 K75 @k75retro.blogspot.ca
2011 Moto Guzzi V7 Racer
http://k75retro.blogspot.ca/
    

7Back to top Go down    Re: K1100 Throttle Bodies On A K75 on Sun May 04, 2014 2:50 pm

duck

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You didn't mess the silver screws between the TBs, did you? Perhaps the vacuum tube on #3 is clogged. I'd try cleaning it out with a piece of wire down the brass vacuum tube.

BTW: The other day I measured the intake port on a K75 cyl head. 31mm so I'm not sure if this mod would make a material difference.


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S
14 Yamaha WR250R
http://www.ClassicKBikes.com
    

8Back to top Go down    Re: K1100 Throttle Bodies On A K75 on Sun May 04, 2014 3:03 pm

robmack

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I didn't touch the Sacred Screws at all. Paint is intact on them so the K1100 PO didn't mess with them either.

I'm fairly certain that the air ports were clean. The TB assembly was pretty cruddy when I received it in the post so I thoroughly cleaned them with carb cleaner and WD40. I remember checking all the holes but I may have missed something.

If air is being pulled through some other part of the TB, will vacuum show up as zero on the manometer? After thinking about this for a while, I'm suspecting the K75 pivot shaft, because that is the only part I've changed on the entire assembly. Maybe the rubber shaft o-rings are not sealing properly and air at idle is being drawn from around the pivot shaft on Cylinder 3 TB.


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Robert
1987 K75 @k75retro.blogspot.ca
2011 Moto Guzzi V7 Racer
http://k75retro.blogspot.ca/
    

9Back to top Go down    Re: K1100 Throttle Bodies On A K75 on Sun May 04, 2014 3:09 pm

robmack

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duck wrote:BTW: The other day I measured the intake port on a K75 cyl head. 31mm so I'm not sure if this mod would make a material difference.
Is the intake port on a K100 larger then? In the other thread, those who have done the mod on a K100 rave about the change in characteristics of the bike. That's where I misread the 3mm different in port size; I must have thought that up myself. You're right in your measurements, the butterfly valves are within 1mm of each other.



Last edited by robmack on Sat May 10, 2014 11:23 am; edited 2 times in total


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Robert
1987 K75 @k75retro.blogspot.ca
2011 Moto Guzzi V7 Racer
http://k75retro.blogspot.ca/
    

10Back to top Go down    Re: K1100 Throttle Bodies On A K75 on Sun May 04, 2014 3:09 pm

duck

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Do you get any vacuum if you rev it up? What did you put on the port on the back of it?


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S
14 Yamaha WR250R
http://www.ClassicKBikes.com
    

11Back to top Go down    Re: K1100 Throttle Bodies On A K75 on Sun May 04, 2014 3:12 pm

robmack

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duck wrote:Do you get any vacuum if you rev it up? What did you put on the port on the back of it?
No, no vacuum. In fact, vacuum drops in all cylinders towards zero as revs increase.

I sealed up the back ports with rubber caps (1/4" if I recall). These caps are visible in the pictures on the blog.


__________________________________________________
Robert
1987 K75 @k75retro.blogspot.ca
2011 Moto Guzzi V7 Racer
http://k75retro.blogspot.ca/
    

12Back to top Go down    Re: K1100 Throttle Bodies On A K75 on Sun May 04, 2014 6:56 pm

charlie99

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sounds like that port structure either side of the butterfly is blocked rob
(or something is holding open the valves )

can you spray some carbi cleaner through the port top to bottom or did you check before assembly ?

inlet port size on the k100 looks to be 31.76 mm at the face of the head .


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cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

13Back to top Go down    Re: K1100 Throttle Bodies On A K75 on Mon May 05, 2014 3:32 am

Rabidchiwawa007

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Compression test just to be sure, before digging in to anything major.


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1968 BSA Lightning
1991 BMW K100RS 16v with K1100LT fairing
    

14Back to top Go down    Re: K1100 Throttle Bodies On A K75 on Mon May 05, 2014 2:59 pm

robmack

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I'll do a compression test later this week. I hope I haven't got ring problems because there was nothing to indicate taht before I began my teardown a year and a half ago.

I sprayed carb cleaner around the area I suspected, TB3 pivot shaft. I used one of those straws in the spray can to make sure that the area could be precisely isolated. I found that the idle RPMs consistently rose slightly when I sprayed around the shaft where it exited to the TPS switch. Seems that the seal is failing in that area and I'll have to tear off the TBs to examine them.

I will also do a thorough recleaning of the TBs while they are off to make sure all the ports are clear.

I was reading some earlier posts about TB syncing and Themason emphasizes pinching off the vacuum hose that goes to the fuel pressure regulator when doing the resync. I didn't do that. It may have an effect but I'll recheck later this week.

Thanks very much for the suggestions.



Last edited by robmack on Mon May 05, 2014 3:16 pm; edited 1 time in total


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Robert
1987 K75 @k75retro.blogspot.ca
2011 Moto Guzzi V7 Racer
http://k75retro.blogspot.ca/
    

15Back to top Go down    Re: K1100 Throttle Bodies On A K75 on Mon May 05, 2014 3:12 pm

Rabidchiwawa007

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People say it's best to get a T style connection for syncing the vacuum on the first TB. That way the FPR vacuum hose can still be connected while you set the vacuum on the TB. In my opinion, it's just important to have a consistency throughout the entire process.

I just disconnected the FPR vacuum hose from the first TB when I did my sync, then plugged the 1st TB with a rubber cap, synced all the TBs with the hose still disconnected, then reattached it.

It is possible it could make a difference when reattached. You'll just have to listen to the possible difference in idle. Obviously, this isn't the greatest method for people wanting a super well tuned sport running bike, but my bike runs and idles pretty damn well.

This part is another topic of great debate on the forum.
I found that when I disconnected the FPR vacuum hose, the bike idled smoother and wasn't as luggy in the low end. Much smoother and easier to ride at slow speeds in 1st / 2nd gear. It didn't stutter as much in idle, and was a much more consistent powerband throughout the RPMs. I haven't noticed a loss in mileage, or any negative side effects. My FPR was brand new when I put it in a little under a year ago. Just something to think about. (I have the 1992 k100rs, 16v, with the MOTRONIC injection system, but I believe others have had similar results with the L-Jetronic system.)


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1968 BSA Lightning
1991 BMW K100RS 16v with K1100LT fairing
    

16Back to top Go down    Re: K1100 Throttle Bodies On A K75 on Mon May 05, 2014 3:40 pm

duck

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best to get a T style connection for syncing the vacuum on the first TB.


+1


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S
14 Yamaha WR250R
http://www.ClassicKBikes.com
    

17Back to top Go down    Re: K1100 Throttle Bodies On A K75 on Tue May 06, 2014 2:08 pm

k-rider

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This part is another topic of great debate on the forum.
I found that when I disconnected the FPR vacuum hose, the bike idled smoother and wasn't as luggy in the low end. Much smoother and easier to ride at slow speeds in 1st / 2nd gear. It didn't stutter as much in idle, and was a much more consistent powerband throughout the RPMs. I haven't noticed a loss in mileage, or any negative side effects. My FPR was brand new when I put it in a little under a year ago. Just something to think about. (I have the 1992 k100rs, 16v, with the MOTRONIC injection system, but I believe others have had similar results with the L-Jetronic system.)




interresting that the milage didnt go down ,since this mod should raise the fuel pressure a litlle at the injectors




k-rider


18Back to top Go down    Re: K1100 Throttle Bodies On A K75 on Fri May 09, 2014 9:51 am

robmack

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Last night I had time to remove the TB assembly from the K75 and inspect it. This is what I discovered.

1. The butterfly valves were not positioned correctly relative to each other and consequently, had different degrees of open-ness. The butterfly valve on TB1 was almost sealing up the throat of the TB; the gap was a little larger on TB2; and TB3 was open the most, revealing almost 0.2mm of space between the valve and the TB throat. These differences correspond with the vacuum readings I was getting. When reassembling the TB, I took extra care in positioning the butterfly valve, more care than I observed originally. I made sure that the valve would very precisely fit the TB throat. When I had the TB assembly back together, I did the forbidden and adjusted the interlink screw between TB2 and TB3 to close up the valve opening in TB3 and make it equal to that opening I observed in TB1.

2. Air was leaking in through the pivot shaft at the TPS because of excessive lateral play in the shaft. When I removed the butterfly valve from TB3, I could move the shaft back and forth almost 2mm. I compared this play to the play in the K1100 TB I removed originally and there needs only to be a fraction of a mm play. I then compared the pivot shaft from the K1100 TB and also from the original K75 TB. I discovered that the cir clips were in different relative positions. The K75 cir clip is positioned nearly 2mm further along the shaft than the K1100. This difference accounts for the width of a rubber washer (there is only one rubber washer that seals the shaft at one end of the K1100 TB but two washers that seal each end on the K75 TB). I added two 1mm thick washers to the shaft to take up the slack and eliminate the lateral play in the shaft.



3. I spent some time cleaning all three TBs again. This time I used a pipe cleaner and acetone to clean the bores of the various inlet ports. I made absolutely sure that they were clean of all residue and fully open.

I'm ready to reattach the TB assembly and try to sync them again. With the base adjustment of TB3 set, I expect the Carbtune readings to be closer together. From this point, I'll fine-tune the interlink screws and then set the air bypass screws, as outlined in Rob Lentini's process. Hopefully, I've solved the air leakage problem as well.


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Robert
1987 K75 @k75retro.blogspot.ca
2011 Moto Guzzi V7 Racer
http://k75retro.blogspot.ca/
    

19Back to top Go down    Re: K1100 Throttle Bodies On A K75 on Fri May 09, 2014 1:05 pm

charlie99

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good find rob


I had to redo the throttle bodies on the k100 recently ...ones that were unfamiliar to me (from someone else ) ...I couldn't find a happy position for an idle that was smooth, as some one had adjusted the 2 to 3 linkage at some point in the past..
I chose to alter the linkages manually without some reference gauges androughly altered by ear and feel of the bike under acceleration and deceleration ... additionally I had visually noticed some lag on idle up - choke tb positions between the inner and outer bodies ..( I guess as they age some slight movement occurs ..although not apparent how that happens, wear I guess )which I left alone at that time .

after the bottom end rebuild, albys fantastic carb sticks helped me settle that observed lag of the outer tbs ,to something way better , by adjusting the apparent laggy ones to now unnoticeable differences ...the bike now rides and idles like a champ and very consistent closure at all occasions to idle like a new one .


best to open the bypass screwsto 1 turn only on each, thenattach the carbtunes and take the throttle to about 3k and notice the vacuum changes as it accelerates and decelerates to that .

make suitable adjustments on the linkages so that they all sync a bit better as the revs increase and the vacuum decreases ..you will get a feel for it as you make adjustments I guess .

alternatively as others have posted previously, the use of a drill bit or several of the same size , could help establish an opening synchronisation in relation to the butterflies.

just make sure that the bypass passages,needle and seats are impeccably clean before hand .
I have noted on several occasions that a fair amount of carbon buildup (possibly from blowback from the inlets valves and induction of breather tube vapours etc ) do seem to coat the passages and needles with some particularly tough to remove coating of crap ( a good solvent and an overnight soak often helps remove it, along with pipe cleaners and acetone ).

all the usual disclaimers apply ...like getting the clearances for the valves correct before starting , rubber injector seals all sorted and tb rubbers top and bottom repaired ..sealed properly along with good needle valve seal rubbers .

after adjustment then set the idle synchronization from theinitial "1 turn pre-set" and idle screw on the choke lift bar ...they should line up to a very similar position of turns out .


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

20Back to top Go down    Re: K1100 Throttle Bodies On A K75 on Sat May 10, 2014 10:21 am

robmack

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Sorted!!

The K1100 throttle bodies are fully synched and functional on my K75.

I reattached them and the bike fired up but still ran rough. Some debugging showed up a failing injector in cylinder #1. Replaced that and she ran.

I loosened the inter-body lock nuts, put the Carbtune on the vacuum ports, fired up the engine and screwed in the air bypass screws until seated. I used the fast idle cam to maintain 1500RPM. The initial reading showed imbalance with cylinder #1 drawing significantly more vacuum than the other two. I carefully adjusted the inter-body screws to get balance between the three readings and succeeded. Below is a photo of the best balance I could achieve over the RPM range 1200 - 2500:



I locked the settings at this point. Once that was done, I unscrewed the three air bypass screws to one turn each and took off the fast idle because it was no longer necessary. A couple of small adjustments on TB3 brought sync to the assembly at idle:



Idle is rock steady. Went for a ride and the "butt-dyno" indicates more apparent torque in the low revs and apparent HP in the mid and high ranges. I have no empirical data to support this claim; it could just be euphoria at finally getting the stuff to work.

Signed -- One Happy Camper!


__________________________________________________
Robert
1987 K75 @k75retro.blogspot.ca
2011 Moto Guzzi V7 Racer
http://k75retro.blogspot.ca/
    

21Back to top Go down    Re: K1100 Throttle Bodies On A K75 on Sat May 10, 2014 11:15 am

Two Wheels Better

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If a 'sense' of something is enough I'd say you DO have empirical evidence! Congrats on getting 'er sorted. Sometimes we just have to rehash things, take a coupla steps back to move forward.


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'77 R75/7-1000cc, '87 K100RS, '93 K11/K12 Big Block, '94 R100R Mystic, '03 K1200GT, '04 R1150RT, '06 K1200R, '07 K1200R & 2009 K1300GT
    

22Back to top Go down    Re: K1100 Throttle Bodies On A K75 on Sat May 10, 2014 9:26 pm

charlie99

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hooray !!!

ride well rob

can i see a cheezy grin over there ?


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cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

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