I have a set of Mikuni RS38's off my gixxer project bike.  I keep thinking about pulling two of the carbs and sticking them on the GS.  Has anyone ever ran flatslides(I'm guessing it's been done) and what size did they use?  That 5mm size difference kinda scares me.  They were big on my gixxer 750.  

I know all about killing the bottom end with flatslides too, so please save yourself the time and trouble if you want to lecture about them.   :nana:

well, some have run 36mm. but i think to run the larger carbs, you need to make it breath much better,bore port and cams and good luck on the jetting.

I have a set of 34mm Keihin CR carbs that were on a running 547 motor with MC cams and a ported head. It was JamesG's motor. I have not run this motor or the carbs yet but I plan on putting them on my 555.

38's were stock  on 88 slingshot 750's
and one of the 750's or 1100's had 42's a canadian model i think....

aren't RS's round slides ??

Yea canadian 88 750's came with 40's ...
Cool.
Srinath.

US 88 slingshots came with 36 CV's.  

Thanks, I had a feeling they'd be way too large.  I guess I'll just keep them for my gixxer.

Bet they would work really well on a GS650 or 750 twin

I've been running Kehin FCR 35s on my racebike
Ported, Cams, Yosh pipe, High comp JE pistons, 513cc.
Ran the same carbs on the GSXR head motor (513cc). Just went up 1 size on the mains (152 to 155). Sudco set the carbs up. Never had to do more than move the needles and change main jets.
Just mounted a set of FCR 39s. Told Sudco what I was running.
They came with 170 mains. After adjusting the air screw for smooth idle, I only had to drop the needle 1 notch. Just running up and down my street, they seem to work great.
I have a set of Mikuni 36 flarslides. They work but aren't quite dialed in the way I'd like. I'd be willing to let them go for $300. They are virtually brand new. And are set up for the stock GS throttle.

Quote from: Bob BroussardI've been running Kehin FCR 35s on my racebike
Ported, Cams, Yosh pipe, High comp JE pistons, 513cc.
Ran the same carbs on the GSXR head motor (513cc). Just went up 1 size on the mains (152 to 155). Sudco set the carbs up. Never had to do more than move the needles and change main jets.
Just mounted a set of FCR 39s. Told Sudco what I was running.
They came with 170 mains. After adjusting the air screw for smooth idle, I only had to drop the needle 1 notch. Just running up and down my street, they seem to work great.
I have a set of Mikuni 36 flarslides. They work but aren't quite dialed in the way I'd like. I'd be willing to let them go for $300. They are virtually brand new. And are set up for the stock GS throttle.

Don't tempt me like that.  You're running the GSXR head on your bike?  Would you be interested in a possible trade?  I have an 88 slingshot engine that I lost #4 on.  #2 and #3 could use new exhaust valves, but otherwise they're fine.  I could give you either the head or the complete engine.  

email me if you want to discuss this further.  
sprinklerhed@earthlink.net

Sorry. I'm not looking to trade the Mikunis.
Would rather have cash.

Let me see about selling off some extra parts I have laying around.  I might go ahead and sell off my Mikuni RS38's.  

How off were your flatslides?  I'd be putting them on a bike that doesn't really have anything done to it other than jetting and a slip on right now.  Pretty stock in my opinion.  As soon as I pick up my Speed Triple in May I might look into getting some head work done on the GS.  

Just how hard is it to do the GSXR head conversion?  What kind of rear wheel horse power are people seeing after that conversion?

Quote from: SprinklerheadLet me see about selling off some extra parts I have laying around.  I might go ahead and sell off my Mikuni RS38's.  

How off were your flatslides?  I'd be putting them on a bike that doesn't really have anything done to it other than jetting and a slip on right now.  Pretty stock in my opinion.  As soon as I pick up my Speed Triple in May I might look into getting some head work done on the GS.  

Just how hard is it to do the GSXR head conversion?  What kind of rear wheel horse power are people seeing after that conversion?

The carbs are pretty close. I'm going to put them on my 89 and try to get them dialed in better. I just built a fresh stock motor for it. It has an advancer and yosh exhaust and pod filters on the carbs.

Mounting a gsxr head is just part of the picture. It is oil cooled, and I'm not sure if the stock oil pump can handle all that. That's why I installed a second pump driven off the transmission. All this requires custom machining. So unless you have a milling machine, the labor cost will make it way too expensive.

I don't know how much power I'm getting. The last time I was on the track it was a dead even race down the straight against a 04 SV650.
I think they put out around 74hp. That was with the FCR35s.
The new FCR 39s should do better.

I'm only an hour away from you.  I just found a yosh pipe on ebay...If I get the yosh pipe, I could always ride down there and swap the carbs at your place.  That is if you have extra jets.  I'm not sure what happened to my old collection of jets, I need to go through my boxes of parts.  

If you have access to milling equipment, I wouldn't mind talking about possibly having you do some of the work if you'd want to.  Any problems with snapping cranks?  Did you add a GSXR top end oiler and/or a top end oil cooler?  

My main interest used to be the old oil boiler GSXR's, till I dropped a valve and blew my engine in my slingshot.  I was borrowing a friend's 89 GS500 for awhile, and at first I was pretty unimpressed with it, then I started getting better at making up for the lack of power and before long I was keeping up with R1's up on 9.  I liked it enough that I bought my own.  My only problem with it is that I absolutely hate working on CV carbs.  Give me flatslides anyday.  I don't mind the lack of power on the bottom end either.

How is the dead spot at 6K with the flatslides and the Yosh pipe?  I know with just the Yosh it's pretty bad.

email me if you like, and we can discuss this further.  I do want your flatslides.

I just realized that you're the one that did the GSXR swingarm conversion.  I was planning on doing that on mine.  I have an 88 GSXR rear end that I'm going to be transfering over.  The only thing I couldn't figure out was where you mounted the brake arm.  Did you drill the frame and mount it like the GSXR has it mounted stock?

I also plan on swapping over my 88 GSXR front end.  I read what you said about it being heavy, but I already have it and a GS frame is cheaper than a set of USD forks.  I don't plan on racing it either, I have sidecars to get my track thrill.  Just eyeballing it, it looks like the headstems are identical between the two front ends.  What did you do for the turn stops?

QuoteGive me flatslides anyday

But, they are flatslides, are you refering to the Mechanical flatslides maybe?

Quote from: Blueknyt

QuoteGive me flatslides anyday

But, they are flatslides, are you refering to the Mechanical flatslides maybe?

Flatslides as opposed to CV carbs.

Quote from: Bob BroussardI don't know how much power I'm getting. The last time I was on the track it was a dead even race down the straight against a 04 SV650.
I think they put out around 74hp. That was with the FCR35s.
The new FCR 39s should do better.

Thats impressive