Hi all,

Does shimming the needle have anything to do with the carb farts. I just spoke to the dealer. They said their jetting solution for exhaust and breather are: 42-45 / 180-185 / shim the needle and cut the spring. I wont cut the spring, but will the needle shim help with the carb farts or is it better to go to a 48 slow jet?

Thanks,

Mark

 

Carb farts and pooping are functions of the air/fuel ration being less than optimal. So, yes, shims have something to do with that.

I wouldn't advise cutting the spring. That creates some unpredictable results. But the 45/185 jets with shims are the correct next step whether you go with a jet kit or jets/shims alone. I think most advocate 2.5 turns on the mixture screw to start. Reading plugs is tricky these days due to the additives in the gas. But between that and farting and popping, you'll know if you need to adjust beyond that.

Should you go with a 48? I'm going to say no. Consider the jets to be course adjustment and the shims are fine tuning. The 48 is going to be too big a jump. Start with the 45 and shims, Only go to a 48 if you need more than 3.5 turns on the mixture screw with a 45 and shims.

Now the disclaimers:
1. Every engine is different. What worked for me might not work for you.
2. Get a second opinion, third opinion, etc. Several smart guys here and elsewhere with good info on jetting and tuning.
3. Check out the DIY section for good info on CV carb jetting.

Good luck.

 

Thanks Benson,

I will try the needle shim this weekend.

I hope that does it.

Mark