So I took down my carburetors and cleaned them. They weren't bad, actually. The pilot screws were all out 2.5 turns. As there was literally no sign anybody'd ever done adjustments to this bike since 1996, I have to assume this was factory.

I looked at the manual and it claims that 49-state (or 56-state, if you're an Obama fan LOL) models are supposed to be "1 - 2/4" out from seated, which I take to mean 1.5 turns. As mine were out 2.5 turns, I'm wondering how they should go back into the bike - at spec, or at their prior state of richness?

 

Did you look at the jet size? From my understanding if they are bigger than stock it changes the pilot adjustment. I run 142 and 145 in mine and had to adjust my pilot to 2 turns out. If your jets are stock i would adjust the pilot back to stock.

 

did it run fine before you cleaned the carbs? if so take them back to 2 1/2 turns out.

 

This.

 

It ran pretty darned well at the 2.5 turn interval, but only if the idle was set to 1400 rpm or more. The stock idle setting of 1200 rpm would just cause the bike to slow down and die. Jets are 138/135 (stockers, I believe). You know, I live at 5200 feet; you'd think that the mixture screws would be turned IN from 1.5, instead of OUT an extra turn.

Makes no sense. In means "leaner," right? Means, "biased towards less fuel," right? I wonder if the goofy higher idle I needed was because the pilot jets weren't optimized?

There's some special tuning procedure in the shop manual; you have to first balance the carbs at a higher idle (like 2k), then you can bring the idle down to 1200 and do the pilot screw adjustment.

ETA: The bike DOES have a can on it - a Two Bros CF unit. I wonder if the prior owner retuned the carbs for this? Maybe the lower back-pressure of the non-stock can caused the owner to richen the mixture somewhat?

 

UPDATE:

2.5 turns out was, I guess, a good starting point. I reassembled the carbs and put them back on the bike. I worked very slowly and carefully, making sure that I did not leave an air leak anywhere, and put everything back to stock. After about a minute of cranking it fired up, and is running picture-perfectly.

I guess I will make an effort to balance the carbs and adjust the pilot screws next. I am not sure how it may improve the operation of the bike, but it is part of the job.