GS450 Idling

[ssco156]

I apologise if this issue has already been covered in the forum; my right cylinder seems to be mis-firing when I start the bike. If I rev the bike to say 2000 rpm, the misfire disappears. Once it warms up, the bike seems to idle and go well. I have checked the spark plugs and the colour is right. I have also looked at the input boots and they seem alright. Anyway, I would think that an air leak would cause problems all the time rather than the first few minutes. Could the pilot screws need adjusting? Any help will be greatly appreciated - thanks

[tom203]

Do something simple first- remove spark plug cap and cut plug wire back 1/4 inch.
Then suspect the right carb's enricher circuit.. might be plugged from sitting - not enough fuel at startup or idle when still cold. Did you just get back up and running?

[Oldman99]

I had a lot of issues with mine when I first got it. Check the o-rings near the idle screws.
Tom203 is correct as well about the cleanliness. Stock air cleaner?

[Steve]

Problems when cold that disappear when warmed up also leads me to suspect valve clearances, but good spark and sufficient fuel (already mentioned) are also necessary.

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[ssco156]

Thanks for your response - no, the bike has been in use regularly for the past 2/3 years with stock air-box. I will shorten the spark plug lead and see if that works. I also want to check the valve clearances, although the compression is just over 150. After that, it's the 0-rings near the idle screws and I also want to confirm if the petcock vacuum pipe is connected to that cylinder. If it is, could be possibly that causing the misfire

[ssco156]

You were right! The right spark plug cap was barely making contact with the lead; I cut off the tip of the wire back and screwed in the cap. The bike is now working as it should. As they say, you should always start with the simple things. Appreciate your help.