Still got a misfire

[solorider]

I have stripped the carbs 3 times and checked the coil leads and I still have a slight misfire, which I have narrowed down to cyl 1, my next task I think is have the rocker cover off and check the valve clearences, I would do a compression test but I don't have a 10mm adaptor.

[solorider]

The misfire or splutter is just over tickover, and it is till 2k revs, I have had the carbs apart 3 times, I have just ivanised the carbs which has made no difference. The misfire I mentioned was the spark plug wells full of water, I have fitted new plugs because of water in the plug holes, and the plugs starting to corrode, I know the plugs were not at fault, I did have an issue with no2 spark plug cap not sitting right but that is now slitting properly.

[Falcon 269]

Dismantle the plug caps and clean up the internal components.  Look down the end and you'll see a crosshead screw slot ... that's your way in.

Also, if you haven't already tried it, cut 1cm off the end of the plug lead to ensure you've got a good core-to-cap screw fixing.

[shrekster]

The standard Yamaha plug caps are not the best quality in my experience. I noticed this by accident on my mates fazer 600, fired the bike up in his garage when it was completely dark and noticed all 4 caps were showing visible sparks on the outside of the caps. They were arcing all over the place, spoke to a friend who is a  Yamaha technician who said he changed all of his own bike caps for jet ski ones. I have done this on both my Fazer 1000 and my R1 and noticed a smoother idle especially on the Fazer.

Jim.

[unfazed]

Sounds like a piece of metal in the pilot system from the Ivanising modification.
If misfire/splutter is one cylinder then it is most likely carb related.
Swap the coils and plug cas and see it it changes. If it does its plug caps if not its the pilot circuit.
When you had the carbs off did you remove the pilot screws and blow out the orifices?
Somebody on the forum had this problem and posted it some time ago

[solorider]

Sounds like a piece of metal in the pilot system from the Ivanising modification.
If misfire/splutter is one cylinder then it is most likely carb related.
Swap the coils and plug cas and see it it changes. If it does its plug caps if not its the pilot circuit.
When you had the carbs off did you remove the pilot screws and blow out the orifices?
Somebody on the forum had this problem and posted it some time ago

The running issue has been there long before I ivanised the carbs, the pilot screws have been out several times and all the orrifices have been blown through with an airline,  the carbs are clean with no signs of any dirt varnish or anything else for that matter, the plug leads could be the cause as it was mentioned that they had a similar problem and stripping down the plug cap and cleaning cured the problem, I am looking into fitting stick coils but have to do some more homework before trying again.

[unfazed]

Good to see you got it sorted, did not realise it was happening prior to Ivanising.
I had a similar problem a few years ago on a 600 fazer and changing the cap cured it. When I dismantled the old cap I found corrosion between the resistor and the brass contacts. Cleaned it, sprayed with WD40 and used it later on a 600 with a broken cap and it has been working fine since. (Well he has never come back to me about it).
I posted a piece on fitting stick coils yesterday, not a mod I would go with as there is a real possibility of burning out the power transistor of CDI.
See my post reply in http://foc-u.co.uk/index.php/topic,11291.0.html

[solorider]

Well my low end misfire/splutter is now history, one or the leads had corrosion on the internal copper strands and when I screwed the cap back on the pin inside the cap sheared probably because of the corrosion.