750 carb swap tips, anyone?

[Anonymous]

Hi there,
I have a 750 Kat, 1981 model 16 valve engine. It currently has the standard 34mm CV carbs and a pipe. At some stage I'll do a top end freshen up and probably will put in a big bore kit. I'm eventually doing a monoshock rear so the airbox will have to go. I'm told that CV carbs often play up when there's no airbox and I'd like a little more direct throttle response, so I thought I'd look at swapping in some conventional carbs off a GS or KZ etc. Does anyone have any thoughts on what would be the best bike to source them from and what size would be right. All my jetting experience has been on big bore dirt 4 strokes with FCR carbs so some jetting tips would be great, too.
Thanks.

 

[Billy Ricks]

You basically have about 4 choices. One would be to get a jet kit for your existing carbs for pods and pipe. Another option would be to get a set of 29mm smoothbores from an earlier year. At one time this was the hot ticket for the 750 motors. Third, get a set of slingshot carbs from the late '80s-early'90s GSXRs. Last and most costly would be a set of Mikuni 34mm RS flatslides.

 

[Anonymous]

Well, that about covers it I guess. Thanks a heap. I've seen the 29mm carbs on ebay at reasonable prices. This would be from GS1000's or KZ1000's, right?

 

[terry]

I wouldn't go with the 29mm carbs Greg, if your Kat is running 34MM carbs now, the inlet tracts are about that as well, and I think it'd be difficult to get some "stepped down" rubber manifolds to allow the fitment of the 29mm carbs.

The 29mm Mikuni smoothbore carbs were very popular with early 8 valve GS750/1000 engines, but they had similar sized inlet tracts.

My advice (for what it's worth) would be to go for a set of early GSXR750 carbs, I believe they'll go straight on to your engine, are much lighter, and work well with pod filters. Cheers, Terry. :twisted:

 

[Anonymous]

Terry,
These are the "slingshot" carbs? I saw an early slabside 750 at the Vic Market the other day and it had non-CV carbs. And slingshot stickers. hehe. So are they 34mm? Don't remember ever seeing them on Ebay, I guess I'll have to hit the wreckers.

 

[oldschoolGS]

1985 GSXR750 had 29mm, 1986 had 31mm and the 1988-89 750's had 36mm carbs. I would think the 36's would work very well on a lightly modified Kat1100. I have used 1986 GSXR1100 34mm carbs on my modified 1983GS750ED for many years with excellent results. Good Luck, Ed.