View Full Version : carb trouble

03-10-2010, 11:39 AM
i have a '80 Suzuki gs850g. im pretty sure i need to re-jet my carbs, i just have no idea how to determine what size im supposed to use.
a little info to help:
it now sports 4 cone filters and i cut the megaphones off. i have some people telling me to just put some sort of exhaust back on to create more back pressure. i dont really know what to do. any help would be awesome.

03-10-2010, 8:30 PM

If it has to do with a GS, those cats can tell you.

03-10-2010, 8:36 PM
Read your plugs...Rule of thumb I have heard before is go up one size for pods, and go up one size for open exhaust...Fine tune from there...

03-10-2010, 11:25 PM
You can add a little backpressure buy adding end caps if you want. But you will need to go up 2 maybe 3 sizes in your jets. You must be running super lean at this point. Your exhaust is likely hot enough to light a cigar in five minutes or less. My suggestion is to go up 3 sizes on both jets and that should get you in the ball park. Once you've done that read the plugs. Black is too rich. spotless is too lean. You want the plugs an ashen off white color. When they are jetting and mixture are right. If the exhaust still has popping it needs a little backpressure.

03-11-2010, 8:47 AM
thanx guys. it is running lean as hell. i can bearly get it to idol and when i try to give it some gas, it just stalls out.

03-11-2010, 8:50 AM
i forgot to ask; do i need to sink the carbs before checkin my plugs? also is there a way to sink them off the bike? there isnt much room to work with in the stock frame.

03-11-2010, 9:36 AM
If the linkage isn't changed between carbs the sychronised settings should remain unchanged. No they don't need to be synchd to read the plugs. Air fuel mixture is pretty much the same. Synchronizing the carbs is primarily assuring all open at the same time at the same rate.

03-11-2010, 11:07 AM
oooohhhh. that makes sense. i was under the impresion that synch'ing them adjusted the air/fuel intake into the engine. glad i asked. im pretty sure the linkage has been moved around since the carbs have been off the bike three times.

03-11-2010, 11:11 AM
what constitutes a "size" in jets? is it whole sizes? or does each incroment count as a size? figure ill just get a jet kit from the local suzuki dealer. the kit is $125.

03-11-2010, 5:59 PM
www.jetsrus.com Fast shipping and they have jets for everything. I had Honda Dealer tell me over 100 for jets on my DOHC 750 and I think I paid 15 dollars from JetsRus. They have all kinds of sizes listed there.

03-12-2010, 7:51 AM
thanx dude. im all about saven the green.