Mikuni BS34's, and Jetting suggetsion?

My bike runs pretty good, except now its hard to start, hot or cold. Once running, its ok till it gets really hot. Then it stammers at low throttle/rpm. It has a open 4-1 pipe on it now, so I'm under the impression that its leaned out some.

I have 37.5 pilots, needle clip in middle, and 130 Mains.

Pulls pretty hard thru mid. Not so much after 2/3 throttle, and just ok starting off. Jetting suggestions? Should I go with 40, or 42.5 pilots? or...

Anyone that knows alot about these BS34 carbs, what exactly does the pilot air screw do? Does it add/remove air from the mixture port, or does it actually controll the mixture volume?

Cheers.

having never had mine apart(bought them rebuilt), i dont what kind of needle i have. thinking stock...i m running
40/140 on mine and it runs good...i did notice recently
when the motor gets warm 150-200 upper rpm s arent as snappy as when its a bit colder....i m gonna experiment with
142.5 i have and see if it differs....i have the 1075 kit and 10.5 to 1....might just need the little extra up top...
still snappy down low.....those screws on the top just before the intakes dictate how much of the mixture goes in...i spent a little time on the gs forums asking what the deal was with those...i have mine 3 turns out..if ya get to 4.5 to 5...time for the next jet up.....do yourself a favor
and spring for k and n filters for these....i tried the emgos and they dont work....even with screwed up jetting i noticed a BIG diff with k/n s ....you are too lean for 1000 cc........good luck......hope this info helps....bs34 guys are few and far between..........keith

I have mine only, 1 1/2 turns out. Guess its time to turn them out a bit more...

Thanks man, good info.

I've got a colortune plug on its way, that should make things interesting

Cheers!

my jetting is the same 40/140's...runs like a striped ass ape..

I don't have pods of any kind, just the stock airbox. I tried drilling my 120's out to 130, and I lost some top end.

I have found a local mechanic that is familier with the BS34's. He even had a set to show me a few things!

He said 42.5 Pilots, Clip in middle position, and 125 Mains are the way to go.

I'm not sure, or convinced yet, so we are going to get both the different pilots and mains and try them out. He said he will only make me pay for one set and keep the rest for himself.

Wish I'd met this guy a while ago...

Sounds like I'll have this worked out soon! :laugh:

Thanks all!

just thinking out loud here, but a stock airbox with an open pipe might be tough to dial in...125 sounds kind of lean...ahh but what the hell do i know:laugh:
pm otaker, he s pretty knowledgable with these carbs and get his input.......keith

Yeah, I thought Otaker too...

I don't really know about the jetting either, thats why I want to try as many as I can. Especially if I dont have to pay for them all

Thnax!