36mm GSXR Carbs on an 80 GS1100e

[liloaty]

I'm very seriously considering picking up a set of GSXR 36mm carbs to put on my bike along with a set of pods and either a V&H or Mac 4-1 pipe.

The spacing on the GSXR carbs is 77mm-93mm-77mm and they've been jetted with a Dynojet kit to 120 main and 32.5 pilots.

I'm curious as to how hard this swap is going to be on a scale from 1-10 and also a recommendation for the rejet (preferably a kit, if nothing else just a guess on the jet sizes I'll need) that I'll need to pick up after I pod/pipe the bike with the new carbs.

 

[rapidray]

If you get the ones from a 750 the needles in that jet kit are close. The only thing I would recommend you also get is the throttle switch assembly & cable from the same bike so you won't have cable issues. It is an easy swap & well worth the effort. Ray.

 

[liloaty]

If you get the ones from a 750 the needles in that jet kit are close. The only thing I would recommend you also get is the throttle switch assembly & cable from the same bike so you won't have cable issues. It is an easy swap & well worth the effort. Ray.

So which jet kit would you recommend I put in the new carbs? Keep in mind I'll be putting pods and a 4-1 on at the same time as these new carbs. Also, any idea what kind of HP gains I may see on an 80 GS1100E from all this?

 

[tone]

The carb spacing is correct to fit your bike but you may find they are tight in the rubbers

i doubt you will find a jet kit made specifically for that swap but the last time i did it i used DJ122 mains dj needles & the stock gsxr pilots that was with a fairly open exhaust & k&N dual oval pods its still not an easy job to get the fueling right & every bike is slightly different so what i'd say is buy them, stick them on & go from there

tip..... check that the emulsion tubes have not been worn oval or you will be chasing your tail for days

 

[liloaty]

The carb spacing is correct to fit your bike but you may find they are tight in the rubbers

i doubt you will find a jet kit made specifically for that swap but the last time i did it i used DJ122 mains dj needles & the stock gsxr pilots that was with a fairly open exhaust & k&N dual oval pods its still not an easy job to get the fueling right & every bike is slightly different so what i'd say is buy them, stick them on & go from there

tip..... check that the emulsion tubes have not been worn oval or you will be chasing your tail for days

Do you think it's worth the trouble? Any guess how much power I may pick up from all of this?

 

[liloaty]

Anyone else wanna weigh in on the size of main jets you think I may need for an 80 GS1100e that im throwing a 4-1 V&H pipe, GSX1100R 36mm carbs and oval pods on? Its got 120 mains in it right now? I know the guy above me says 122 but that seems a little small?

 

[GER144]

It's really hard to say what jetting you're going to need, every bike is different. Get the carbs, put them on, and put it on a dyno. Most dyno shops should be equipped with an O2 sensor, that goes into the pipe. This will help you get the jetting as close as possible.
The dyno is the best way to do it, unless you want to spend hours and hours riding it around, checking drivability, and doing spark plug checks.
Make sure the carbs are in good shape, the needles and emulsion tubes are not worn and they are balanced.

 

[liloaty]

It's really hard to say what jetting you're going to need, every bike is different. Get the carbs, put them on, and put it on a dyno. Most dyno shops should be equipped with an O2 sensor, that goes into the pipe. This will help you get the jetting as close as possible.
The dyno is the best way to do it, unless you want to spend hours and hours riding it around, checking drivability, and doing spark plug checks.
Make sure the carbs are in good shape, the needles and emulsion tubes are not worn and they are balanced.

Thanks for the input, I really wasn't looking for someone to provide a magic number that would work on the first try, more a starting point that I can work off of if that makes sense? Any input is welcomed and I will take it all into consideration.

Unfortunately a dyno isn't an option for me as I don't have the cash or the time (I'm in school and have class pretty much during the whole working day)

 

[tone]

Do you think it's worth the trouble? Any guess how much power I may pick up from all of this?

Its unlikely that you will gain much power from this swap the, no more than you would from free flowing pipe & pod filters on your stock carbs, advantages are in drivability & in the easy availability of parts for the newer carbs

the limiting factor for making power is always going to be the head itself

 

[liloaty]

Its unlikely that you will gain much power from this swap the, no more than you would from free flowing pipe & pod filters on your stock carbs, advantages are in drivability & in the easy availability of parts for the newer carbs

the limiting factor for making power is always going to be the head itself

Thanks, this just confirmed my original thoughts on the swap. I'm really hoping to gain a smoother power/torque curve from all that I'll be installing. Is this a fairly realistic goal? I realize I'll probably lose a little in the low end from the larger carbs, but I'm expecting a pretty good response in the mid to high range

 

[RacingJake]

The spacing on the GSXR carbs is 77mm-93mm-77mm and they've been jetted with a Dynojet kit to 120 main and 32.5 pilots.

Remember that DJ numbers are about 10 point's lower than Mikuni number's so your 120 DJ is like a 110 Mikuni.

If you run an open pipe it may run lean on the top end and you'll feel it nose over.

For me anything less than a mikuni 140 main was just too lean, even running 34 CV carbs and pods too back in the day when my GS1100 was still street legal.

Get it together and you'll be surprized how it runs.

 

[liloaty]

Remember that DJ numbers are about 10 point's lower than Mikuni number's so your 120 DJ is like a 110 Mikuni.

If you run an open pipe it may run lean on the top end and you'll feel it nose over.

For me anything less than a mikuni 140 main was just too lean, even running 34 CV carbs and pods too back in the day when my GS1100 was still street legal.

Get it together and you'll be surprized how it runs.

Thats great to know, since jets are relatively cheap I think I'll order a few steps. Would you recommend Mikuni's over DJ? If so, can I ask why? If you prefer the Mikuni jets, is it possible to use the DJ needles that I already have?

Since it sounds like you've done an almost identical swap, do you think picking up a set of 130, 140 and 150 DJs would be a good place to start out?

 

[RacingJake]

Alot depends on how free flowing the pods and exhaust is and if you like to ride around at WOT alot.

I've used the 38 CV carbs off a GSXR 750 and really like then too and their jetted at 165's with mikuni's but that's for drag racing.

Get it running and see how the engine preforms throught the RPM's, if it feels like it's running out of steam or goes flat in high gear it's running lean and bigger jet's are needed or raising the needles is required.

For me I'd go with 140 mikuni jets add a 14 tooth counter sprocket with your pods and exhaust for somemore fun.

If it runs lean PM me, and I'll send you some DJ jets, I got some 132's and 138's that I don't used anymore.

Good Luck

 

[liloaty]

Thanks so much for that info man, that's EXACTLY the kind of info I was looking for. Hopefully all goes well!

 

[litshoot]

This is a perfectly time post for me as well. i'm looking to do a similar swap onto my 77gs750 and this showed up just before i logged on to see if it had been done or could be done. great timing and thanks for the help. would the jetting be far off because of the cc difference.

 

[liloaty]

From what I've read and been told by the extremely helpful guys on this board, you'd be better off going with the 34mm mikunis. If you did decide to do the 36mm, you're jetting would definitely be different

 

[Pulukka]

From what I've read and been told by the extremely helpful guys on this board, you'd be better off going with the 34mm mikunis. If you did decide to do the 36mm, you're jetting would definitely be different

Ive been reading these carb swap topics for a while now and now I have to try it myself, even though I just installed a dynojet kit and K&N:s for my 1980 gsx 1100 last summer and all is working great...

There are guite a lot of these gsxr carbs available here in Finland and even more in german ebay. Now there seems to be a set of 34 mm gsxr carbs available from a 1987 bike:

I suppose these would be suitable for my bike - the slides seems to be flat and carbs appear to be quite clean, why is 34 mm better than 36? What are the benefits when choosing 34 instead of 36 or are there any? Wouldnt 36s give more top end power? Are the 1989-92 carbs better/more modern than these? I?m still stubbornly searching for 89-92 36 mm gsxr carbs but now I popped into these...

what to do, what to do :?

 

[mikluha]

Pardon my ignorance. But aren't GSXR carbs downdraft and GS engines are sidedraft? If you fit gsxr carbs isn't the fuel level going to be wrong (at least tilted). That should affect the operations.

 

[liloaty]

Pardon my ignorance. But aren't GSXR carbs downdraft and GS engines are sidedraft? If you fit gsxr carbs isn't the fuel level going to be wrong (at least tilted). That should affect the operations.

You are absolutely right. I had to adjust the float height level to about 17mm to keep the bowls from leaking.

 

[Guest]

Pardon my ignorance. But aren't GSXR carbs downdraft and GS engines are sidedraft? If you fit gsxr carbs isn't the fuel level going to be wrong (at least tilted). That should affect the operations.

late 80's early 90's gsxr/katana carbs are side draft like the GS if I am not mistaken. I think the '96 srad was the first downdraft head.