Have a 2000 gs. Dynojetted, slides drilled, k@n lunch box, stock exhaust. 134 mains, haven't played with the pilots yet. With cold weather coming I'd like to give it a boost on starting. I'm debating whether to jump to 42.5 pilots, as 40 is the stock on euro gs. And with the aftermarket filter it might be ok. Anyone here run 42.5's?

40 is all a stock engine will take. 42.5 will make for lousy starts - till you rev to 3500 and keep it there as you let out the clutch ...
Leave 40's there. Set floats right etc etc. 42.5 = misery.
A flowed head and high compression motor will run 42.5 or 45 just fine, else, no.
Cool.
Buddha.

Ok 40 it is. And just for knowledge sake. Still learning carbs. Does the increased airflow from the k@n have far less effect on the pilot circuit than the main? So its not neccesary to increase fuel at idle as air flow increases?

So if I'm in Europe with a stock 40. Then put on a high flow filter, I wouldnt go +1 on the pilot to compensate?

Quote from: capz on August 22, 2014, 11:30:52 AM
So if I'm in Europe with a stock 40. Then put on a high flow filter, I wouldnt go +1 on the pilot to compensate?

Nothing you do to a stock engine will take a 42.5 on that stock carb.
We dont jet everything to +1, we jet the EPA strangled US bikes, to the non EPA strangled Euro jets ... aka 125/40.
I've run it with 42.5 cos some Idiot didn't know how to read a manual and where it said air jets are 42.5, he thought it meant pilots were 42.5 ...

I suffered with that for 3+ years on my 89 from 95-98 before I started jetting the thing ... and even so, the last thing I got right was this cos I bought an all stock 90 GS in 98 and noticed it didn't fall on its face @ take off ... so I swap carbs, and the 89 runs great - then I swap bits and bobs ... till I get to the pilots ... till then I blamed the kevlar clutch I had in the 89 ...

Anyway I start looking in the manual, and find 37.5 is the US jets ... and 40 is euro ... and I had 42.5 in the 89. So I start looking for 40 non bleed jets ... and in 98 find it in Canada (where I had moved to in late 98). If anyone remembers the old mailing list ... and the first 20-30 jet packs I sold were sent from canada. I actually sent ti to someoen in mid 99 and then moved back to US in 99, found a friend that needed a 125/40 kit, and found someone I sold it to hadn't used it, and I bought it back ...

Anyway ... stock motor need 40 pilots. Port and flow and cam and high compression pistons ... and you need bigger ... heck you need bigger carbs then.
Cool.
buddha.

good stuff thanks for the info!