Just had my spark plugs out to check them to see how they are looking and they are as can be seen below... Cylinder 4 on the left 1 on the right... Any reason why there is a differance in the collars?

Apart from that they look normal to me

The plug on the right appears to be carbon fouled. All things being equal on the other plugs, it could be too rich a fuel setting or bad plug wire. Try checking the spark on that wire.

The spark itself was the only thing I didn't check, I checked all the other natural things, The coils all have the right resistance on the primary and secondary coils. The HT leads are all measuring good. (They are RAM ones) The only thing I did notice with them is that they don't have as high a resistance as the original one's.

Original one's I believe are 5 or 6K Ohms and the ones fitted are 2.4 apart from cylinder 4 which is 1.4k Ohms

The injectors have all been cleaned and then installed with a new fuel filter...

were the plugs tight as seems a bit of oil on a few of the threads

Hi there, if cil 4 has less air at idle it will be rich and that can mean carbon.
just thinking out loud
Best regards
JAP

Right have had a think about the cause of cylinder 1 showing signs of running rich and what can cause it in one cylinder only...

Sparkplug not working correctly
Dodgy HT lead
Fuel injector leaking
Fuel injector not closing fast enough
Inadequate air flow


Given that cylinder 1 was used as the reference for the others setting up the throttle bodies that rules that out.

Spark plug is firing the same as all the others so have ruled that out.

HT lead resistance is good, no sparking/arching with the garage lights switched off plus is new so have ruled that out.

Dodgy fuel injector then...

Best I pull a bike out from the garage and head over the moors and up to James Sherlock... I couldn't use the K it's still not got it's tank on following the leak.



That will be a shiny new injector to replace the suspect one! I thought about getting a second hand one or a "reconditioned" one but decided that it's worth getting a new one as it's a known condition this way.



Off to fit it to the K and put the now repaired Tank back on. I am going to swap the spark plugs from cyl 1 & 2 so I have a clean spark plug in cylinder 1. and have a look at the condition after my next 4 days riding to and from work as that will rack up 550 miles. It will also be interesting to see what happens to my MPG if that will improve if my hunch that the injector is leaking/allowing extra fuel to pass.

I know that I should have really conducted a pressure test on the fuel line but going to save the purchase of a meter for that till next month! It's been an expensive month buying parts for my car as well as the bike... and then getting a new helmet.... Helmet review will be written this evening... Schuberth C3 Pro

The injector is now fitted to the bike she took a min to start due to having to prime the fuel system again then she started like a dream... I am probably imagineing it but she sounds sweeter....

It's been about an hour since I fitted the new injector and she now starts without any hesitation i would say within a second of pressing the starter but it's less than that its an instant fire!

Makes me wonder if it would be an idea to replace the other 3 :| I know that the plugs don't show a problem with the others apart from a slight dusting of soot.....

hows the compresion test twincarb ....did you do one ?

could it be some ring gap or valve sealing issues or perhaps just an inlet valve stem seal (more likely )?

oh ! just read the result ,,,,good riding ol mate .....let us know if it fixed the issue huh ?

The proof is going to be in the riding over the next couple of days however I have got a good feeling about it.

Jobs for tomorrow get a new rear tyre fitted. Fill the tank up with petrol do a 60 mile test route. Fill the tank again....

See what the mpg is the route I use is a good mix of dual carriageway and twisty hilly roads its not a loop I will come back the same way i went which evens out the ups and downs.... Plus there are some nice bends hehe

Just completed my test route and the results are in.... Fuel consumption has improved:

Original	New Figures
6.8 L/100Km	5.5 L/100km
34.8 Mpg	51.1 Mpg
2.87 G/100mi	2.35 G/100mi

Which by my reckoning I should be able to ride 200 miles without the fuel light coming on!

Imagine what you'll get when you change the other three

I am thinking that after all these years that replacing the other 3 wouldn't be a bad idea if using some very poor mathematical calculations that if the other 3 are just as bad and using a logarithmic scale I have calculated that I would be able to get 97 MPG which would mean I have the most fuel efficient K on the planet hehe

Realistically there is no way that the other injectors are in as bad a state as the one I have replaced and I wouldn't see a 25% increase each time I replaced one! Shame mind hehe.

I am wondering if there would be a 1-5% increase overall to the fuel figure if I was to replace the others. At that small increase it would take a while for them to pay for themselves.

The logical thing would be to get them clean.... Oh I have been there not long ago and they were all given a clean bill of health... Gets you wondering if all they do is stick them on there machine and pump cleaning fluid through them rather than give them any sort of leak testing.

Interesting that. Whats the end of the silencer like? Mine has done 61000 miles starts, runs well have no issues but the end of my silencer is always sooty. Bike returns 50 mpg overall, fast and slow running. After 25 years of running R80's I keep trying to compare the two bikes who's silencers always ran very clean. John

My silencer has got a nice layer of road grime only! no carbon build up at all Considering the build up that I had on the one spark plug its surprising that I have had such a dramatic increase in fuel economy.

I will have a good idea in 5 days time of what daily mpg is going to be as I am back on shift tomorrow I will probably clean the exhaust up before I leave work tomorrow evening and so long as we have a dry spell will be able to see how it is....

Is there much wadding in our silencers? As after all these years I would expect the material to break down with general use and age....

Not going to be riding to work tomorrow.... any guesses from the photo below whats happened?

Did the petrol tank repair fail to live up to expectations?

Paul.

It failed big style! The cats front tyre was sitting in a pool of petrol have got the tank off and will try and get some putty to fix it tomorrow. The stuff I used should have worked according to the packaging

bummer about the leak twincarb

most of us here get somewheres like 5.2 - 5.5 liters per 100 ...some better some worse

good luck with the repair

In the US at least used K bike fuel tanks are cheap and plentiful. I wouldn't try repairing yours.

Over here they seem to command a premium what should be just above scrap value is charged at what I consider a premium rate.... Hmmm

Careful in the shed mate, I can only imagine the smell...
shame about the result, keep your head up , move on.

Bummer TC. I used a chemical metal called Devon to fix mine (hole was big eough to put a finger in - I used a little Bodyfiller mesh to help bridge it and support the material until it set.. Here is the write up

There is a seperate thread showing the 2 repairs that I had to make the first one failed! The garage isn't smelling to bad now I got sand on the fuel over night, bagged it up the next day then washed the floor down.

I am back on the road just a shame the temp is barely above freezing!

Been a while since I did some more fault finding on the bike, and I think it's all tied in still.... I checked the fuel pressure coming from the pump which was showing in the region of 100psi I then checked the fuel pressure with the FPR inline, and got some fluctuating results... up to 60Psi which deff isn't good.

Yesterday I replaced the said FPR with a new one, took her for a spin and I believe she feels a lot better power and engine wise feeling more controllable. This was reinforced today riding to and back from work.

Which is where I had a huge backfire from the exhaust! I had just cranked open the throttle on a down hill section to overtake a line of cars just after I pulled in and backed off the throttle Bang/Pop and nice bright flash from behind me! I know that the TPS is working as I checked the resistance with throttle wide open and shut and they are good. The connector is definitely on and working as you feel the power shut off as soon as you back off the throttle. No change in the MPG of the bike still floating around the 40-42 UK MPG

Any ideas of what I should look at first....

bang and pop is usually a sign that air is getting in somewhere tc ..

since i did my throttle body rubbers (particuarly the lowers ) it doesnt seem to happen much at all now

The rear cylinder gets some oil spray from the output shaft gear, so that plug will always have more crud on it.

just thought to mention leaky injectors at this point ...maybe a clean and service ...replace the rubber seals etc ?

twincarb wrote:Been a while since I did some more fault finding on the bike, and I think it's all tied in still.... I checked the fuel pressure coming from the pump which was showing in the region of 100psi I then checked the fuel pressure with the FPR inline, and got some fluctuating results... up to 60Psi which deff isn't good.

Yesterday I replaced the said FPR with a new one, took her for a spin and I believe she feels a lot better power and engine wise feeling more controllable. This was reinforced today riding to and back from work.

Which is where I had a huge backfire from the exhaust! I had just cranked open the throttle on a down hill section to overtake a line of cars just after I pulled in and backed off the throttle Bang/Pop and nice bright flash from behind me! I know that the TPS is working as I checked the resistance with throttle wide open and shut and they are good. The connector is definitely on and working as you feel the power shut off as soon as you back off the throttle. No change in the MPG of the bike still floating around the 40-42 UK MPG

Any ideas of what I should look at first....

100psi is far too high for the primary pump pressure have you made sure the correct pump is installed it should be 65psi, It's not difficult as many pumps from that era look much the same but work at a much higher pressure or maybe the relief valve in the pump is crook.
Many of the FI systems of that era work on higher pressures but in the last 10 years or so seem to have settled on 3 bar as a standard pressure so pumps are more interchangeable.
With pump primary pressure that high it is quite possible that the FPR can't cope with it and wont deliver the correct pressure (32psi) all the time.
I would not be too concerned about the backfiring for the time being unless the police start to chase you then they might start shooting back.
All I do in finding a pump to use is make sure the pressure and volume requirements are met and the system will work so long as all else is right.
What I have done to clean the injectors is to run some carb and injector cleaner through them with power to them in short bursts then leave with the cleaner in them to soak over night then run some petrol through and put them back in.
If they are dribbling it may be they are had it and need replacement but it can be just some crud stuck in the needle valve.
Don't leave 12v hooked to them for more than 5-6 seconds max as the coils will overheat quickly. In service they only open for a max of 405micro seconds on each working cycle.
When you think about it the injectors do very well with firing 2000 times every mile you ride and they last for 100,000 miles or more without a service.

I will recheck the psi that I am getting on Tues when I have the time to whip the fairing side off again. When testing the pressure from the fuel tank I take it that the pressure will go to a max only and not increase?

The fuel pump I got was one off of ebay the guy is selling them for less than half the price of a normal one and is sold as being the correct one for our bikes.

I am wondering about the injectors they have been professionally cleaned so there shouldn't be any crap in them.... But you can only put trust into the company you give them to. I have replaced one injector due to it being problematic. As you say Rick injectors are normally very reliable esp when they are given constant use, ie with fuel passing through cooling them and the coil being exercised. My car has passed 220,000 miles on the original injectors and show no sign of age. (Should have got them flow tested mind when I had the head off!)

Ride wise the bike is smoother than ever, I had a great ride in this morning with all the power where it should be. Only the one backfire yesterday and none today yet... It may just have been an isolated incident.

I think there is a "problem" with my exhaust, there is something rattling around inside doesn't sound like anything big but am thinking about replacing it with either a new motad or a secondhand original.

All of the Rubbers for the air flow have been replaced now and have been tested to ensure there is no air leaks. So I am confident that there isn't an air leak from that area.

sounds like you have done all the right things mate

how many ks do you have up since the regulator change ?

A leak in the exhaust will draw fresh air in on the over run and the corbon monoxide will ignite and if there is any significant quantity of unburned fuel it also goes bang. I have seen it split a muffler from one end to the other, not on a K but a car

have now done 320Km on the new regulator, I do about 200km a day so the mileage soon racks up!

I pretty much followed all the advice on the troubleshooting guide to try and rule everything out, it definitively lays things down to check logically.

I am thinking about replacing the last 3 injectors still, the only other thing that's not been replaced is the water sensor but I am pretty certain that it's working properly...

I need to check the valves when we have a good dry day.

So the Exhaust may be the culprit... I may make that my next purchase before injectors then...

Slightly off the topic but when the cam chain is replaced with the bottom end aligned up to tdc should the cam shaft sprockets arrows both be pointing true or is it normal for the lines to be slightly off when the chain is connected? The only reason I ask is cause I seem to recall mine weren't completely aligned... am wondering if that would cause any issues with the valves opening and closing. Not to sure how critical it is on the 2v engines....

check the flanges where the headers meets the muffler mate ....i think we have seen a couple of these with cracks recently ...could be the source for the air entry on the overrun ?

if it sounds right tc ...i would be guessing you got it right on the cam shafts

The position of the arrows can vary a small amount but if they are a tooth out it sticks out like the proverbial.
When you check the clearances do it before you touch the spark plugs as carbon can fall from a plug and lodge under the valve holding it off the seat a bit causing you to measure a larger gap than there actually is when running.

Thanks for the advice there guys Can have a check of the headers now, I need to grease the centre stand any how.

Will look at the Valves on Tues when the bike is nice and cold. (Just hope the weather isn't cold!)

I am guessing that if the timing was a tooth out the bike would run rough?

At 11.25 deg per tooth I reckon you would know.

That makes sense.... which is reassuring really!