Preliminary jetting for hot rod GS1000

[Jim W]

I'm looking for preliminary jetting recommendations for my hot-rodded 78 GS1000. I've just installed a set of Weisco 1085 pistons. The bike has a Mac 4-2-1 exhaust, 29mm Smoothbores with K&N tapered oval filters, degreed stock cams, a Dyna S ignition & Dyna coils. It's pretty much based on an old Motorcyclist project bike, but with slightly lower compression. Dynojet told me their jet kit most likely wouldn't work on my engine. The altitude around here is around 450' above sea level & it gets HOT!
Any thoughts?

[tfb]

Jim,

Unfortunately it's practically impossible to give any recommendations -- unless someone out there has done the same or very similar batch of modifications, the fact is that you have some work ahead of you.

But one thing is sure: you'll need to richen things up certainly in the main jet department and probably/perhaps also in the jets that supply the fuel lower down the rev-range. But start with the mains.

The most useful and comprehensive set of instructions I've ever come across for helping us home-tuners do exactly this, can be found at FactoryPro. It's a very clear and useful site. All the best!

Mike.

[SqDancerLynn1]

the 29mm smooth bores throughs a curve into what anyone has done, stock carbs are 26mm & would be jetted different. I don't believe their is a jet kit for the 29s so you will need to get the individual jets. You need to do a plug reading to start

[Pete's GS]

SUDCO recommends these settings for 29mm Smoothbores on the Suzuki GS750/1000: Main Jet--#115, Air Jet--.9, Pilot Jet--25, Jet Needle--5DL31-3, Needle Jet--0.6, Throttle Valve--2.0. I bet that's pretty close. I'd go to a #120 Main Jet to start. If you want to call them it's 323-728-5407.