Stock Main Jet Size

[lordnv]

Hi guys

I've got a 1980 GS850G. Its been somewhat modified by the PO and I'm trying to figure out what he did. He put some cheap crappy foam air filters on it. I'm going to change those out. But can someone tell me what the stock jet sizes are, in particular the main jet? It looks like they might be 115, but I'm not sure...

THANKS!

[Guest]

115 it is.......................

[Larry D]

Hello All, I have a similar question. I have an 81 GS750L,Mikuni BS32SS carbs. It currently has a 4-1 exhaust, which I understand is not stock, 4-2 is. When reassembling my carbs I noticed the main jets have 112 stamped into them. Aren't these suppossed to be 115? Would this be correct if it has been rejetted when the exhaust was installed? BTW,I'm going to keep the 4-1 and return both the airboxes to stock.

[doctorgonzo]

110 is probably (though can't say 100%) stock. The 112 could be where the PO upped it a bit for the pipe. Or it could be a dynojet jet instead of a Mikuni in which case it translates to a 105, which might still be an upping of the main jet if stock is actually 100. Not much help I know. Look for an online manual, starting with Basscliff's site. It will have the stock sizes and settings.

[Larry D]

BassCliff's website (nice update today,btw) says 115 is stock. I'm wondering if 112 would have/could have been installed when a po installed the 4-1 exhaust and if this was correct to do.

[doctorgonzo]

BassCliff's website (nice update today,btw) says 115 is stock. I'm wondering if 112 would have/could have been installed when a po installed the 4-1 exhaust and if this was correct to do.

It COULD have but, that would be wrong. You'd want to go up slightly on the main (like a 117 or 117.5, not sure what sizes they make in that range) not down. You'd also likely want to shim the needle to raise it a bit, or put on an aftermarket adjustable needle.

[Larry D]

You're right again DoctorGonzo..looked at the manual on BassCliff's site. It seems that the main jet is 112.5, making a 112 probably very good for a 4-1 exhaust. Thanks!!

[doctorgonzo]

You're right again DoctorGonzo..looked at the manual on BassCliff's site. It seems that the main jet is 112.5, making a 112 probably very good for a 4-1 exhaust. Thanks!!

If stock is 112.5, then 115 or 117.5 would probably be right for a pipe only. Pod filters is the BIG jump where you get up in the 140s or 150s.

[Larry D]

Right...up not down! I'll see how much a set of 115 main jets are. In your opinion, is it worth it to do, with the only mod being the 4-1 exhaust?

[doctorgonzo]

Right...up not down! I'll see how much a set of 115 main jets are. In your opinion, is it worth it to do, with the only mod being the 4-1 exhaust?

Raising the needle, and richening the pilot circuit MIGHT be enough, but jets are pretty inexpensive.

[Larry D]

I think I'll stop by by neighborhood Suzuki dealer and pick up four 115's. That should do it.
Thanks so much