R100 GS misfire

FatAl

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I've been doing a bit of a rolling upgrade on the bike, fairly recently I've replaced the diode board, coil, ignition module, HT Leads, spark plugs. The bike has developed a stutter/misfire around 2000 to 2500 RPM in the last few days, then runs cleanly up. The carbs have been cleaned and balanced and fresh fuel put in, but I can't fix it. It starts OK and ticks over OK Any ideas?
 
All the time. I think it may be carb related. I am considering replacing the diaphrams as I seem to be running out of options. I might run it down to local bike shop and get them to recheck carb balance and ignition timing.
 
Unlikely the ign timing has suddenly changed,?
Carb balance would be noticeable more,straight off idle,
A local bike shop is unlikely to have enough product knowledge to bottom the issue .
Do you have a good dyno place nearby?
 
Quill exhausts is about 30 minutes away, I know they have a dyno, but not sure if it's a ride in facility. They fitted an exhaust to my Stelvio and then ran the bike on the dyno.
 
Quill exhausts is about 30 minutes away, I know they have a dyno, but not sure if it's a ride in facility. They fitted an exhaust to my Stelvio and then ran the bike on the dyno.
A good dyno man will be able to provide more info in ten minutes than anyone else,
Just needs to be a proper chap!
The exhaust gas analysis will tell you everything you need to know,the challenge is knowing what it all means,hence”good dyno man”:thumby:
 
Quill exhausts is about 30 minutes away, I know they have a dyno, but not sure if it's a ride in facility. They fitted an exhaust to my Stelvio and then ran the bike on the dyno.
How long ago was that?
I enquired about a dyno run with Quill a couple of years ago and they said they'd got rid of the dyno as it had been problematic, I'd had dyno runs there a couple of times previously btw.

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If I read this right you did not have any real problems until you changed these parts???

Check the clip on the new ignition module is secure and if not? make sure its properly connected I had a stutter on my RS it was the clip had not clicked home and it moved at around 4000 rpm if that sorts it the happy days!

If not replace it with the old module and test (Do you have the heat sink paste on the back of it??) Remember you need the heat sink paste or it gets too hot

If that does not cure it replace it with the old module

And if it was me I would retrofit the old components one by one i.e. refit old test If cured? then thats it, if not refit new part and then chose the next part to replace

This is based on the proviso that the problem did not exist pre new parts fitting

Other wise you would be chasing shadows
 
How long ago was that?
I enquired about a dyno run with Quill a couple of years ago and they said they'd got rid of the dyno as it had been problematic, I'd had dyno runs there a couple of times previously btw.

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It was about eight years ago, not been there since.

Dr Farkoff I shall take on board your suggestions.

Thanks Lads :thumb
 
When my R80 G/S had a similar issue and after numerous carb strips I eventually traced it to the coil which was fine most of the time.. but not always.

I know yours has just been replaced, I'd certainly try swapping the old one back in, just in case. In fact assuming you still have all the old parts, it would be an easy exercise to swap them back in one at a time to see whether that highlights anything.

Paul
 
Got it sorted. I found a wire in the nest of wires near the coil exposed and arcing.

Thanks everyone for your input. Al.
 


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