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Need a bit of carb help ??? ok a lot of HELP!

1K views 10 replies 3 participants last post by  MUNKI 
Let's start at the basics. Do you know what the various circuits in the carbs do? Any advice we give will be totally lost unless you have a basic understanding of which circuit does what.
 
A rought idea but im best to say nope,...Im thick as shite
Ok. We'll start with this chart.


Basically you've got four different circuits on a typical CV carb, and you need to tune all four for the bike to run correctly when you alter the intake or exhaust. The strategy recommended by Factory Pro is to start from the main jet and work your way down to the idle mix screws. It's what I've done in the past and it works pretty well.

1. Install pod filters/exhaust/whatever
2. Buy jet kit
3. Increase main jet size until WOT performance increases, then starts to decrease again. That second to largest jet is the one you want on the mains.
4. Start with needle on the highest clip position, so that it sits into the carb as far as possible. Like before, lower that clip until performance at medium throttle increases, then decreases.
5. Repeat step one with the pilot jet to tune low throttle openings. These usually don't need to move a whole lot. My old B12 with full exhaust and pod filters had the stock pilot jets.
6. Set your idle mix screws so that when you blip the throttle the engine speed doesn't dip or hang. If it's too rich, the rpm will drop slightly before picking up, and if it's too lean the rpm will hang high briefly before coming back down.

Do all that correctly and you should have a bike that runs cleanly and gives the best possible performance with the parts you have on it.
 
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