GSXR carbs

[Anonymous]

On further review of the Dynojet website, it looks like the only difference between the kits for the GSXR1100, GSXR750 and the Kat 750, are the sizes of the mains, then needles and other stuff are all the same part numbers. I wil probably go with the late 80's GSXR1100 kit, and the biger jets.

Derrick

 

[HiSPL]

Try the clear fuel line that they sell for lawn mowers. That's what I'm using right now and it works well, with the added benefit of being able to see if the fuel is flowing or not...

 

[pano]

I bought a dynajet kit at:

http://www.overstockpartsgalore.com/jetkitmain.html

it seemed to be the best price I could find

 

[Anonymous]

Hey Pano,
on your GSXR 1100 what size pilots were in them? In the 96 Kat 750 carbs I have installed the stock were 32.5, I went to the 40's from my stock 83 carbs, but I think it is running too rich. It idles ok until it starts to warm up , then the Idle starts to dropp and finally stall.
Also, have you looked at the needles in your dynojet kit? how do they compare to the stock ones? I am also getting some blue balck smoke when I blip the throttle, maybe i shimmed the needles too high?

I guess if it were too easy, it would not be any fun.....but I am tires of having so much fun at idle

Derrick

 

[scotty]

my plan was to leave the needles stock position and just increase the mains to about 15((for my engine) I would say 107 for yours or something close. 130s if you have some flow mods like a exhaust or pods

 

[pano]

I haven't opened them up but the spec sheet says

main jet 122.5
pilot jet #40

The dynojet gsxr needles are sort of fat with a tapered tip. I havent looked at the stockers yet.

I just finished up installing slotted cam gears and dialing them in. I have to close that up and make sure everything is running right with my old carbs before I play with the GSXR carbs.

Man, its gonna be spring before you know it and I got so much to do!

 

[Anonymous]

Thanks guys,
I think you are right Scotty, I may have been a little too aggressive with my initial needle shim, especially since my stock needles have a second taper at the bottom.

Pano, thanks for the look, I think you are going to find that the dynojet needles are radically different than the stockers, at least if they are close to mine. My stock needles are slender and taper down to a more slender size about 3/8 inch from the bottom.
I did some additional digging on the schematics on bikibandit and found that the GSXR1100 carbs changed in 1989. It looks like different slides, and such, The part numbers list for the 86-88 pilot jets do not give a size, but after 89 they are pretty uniformly #30. And the mains as 122.5.
But the stock jets that I pulled out of my Kat carbs are 32.5's.
I guess that I will start by dropping my needles a bit and see how it runs (at least I don't have to pull the carbs to get the needles) and if it is still rich down low, I will put the 32.5 pilots back in.

till next time,
Derrick

 

[Flo]

Gixer-carbs on GS

Gixer-carbs on GS

Hi,
I am new registered in this forum, but sporadically reading it during the last years. Really nice institution, I miss something comparable in Europe...
However to the facts, not boring someone
I got a GS1100. Has Laser 4-1 street legal, K+N dual-filters, 36mm-R-carbs with orig. needles and stuff (whatever it had, I dont even know from which type of Gixer they come) except the main JEts: 142,5.
runs quite fine on the road! No deep holes

maybe a point for someone else to start.

I was a bit surprised, that according to my O2-meter even the idle and lowend mixture is nearly perfect... real o2-testing was not possible, because since I got the o2-meter installed there always was snow or ice or salt on the road... and its no fun to do the fullthrottle testing under these circumstands
Minor changings were necessary to the cable and choke assembly (I got my choke lever from a -E at the handle bar allthough I got an old KATANA).
at least the Gixer-carburators with 36mm diameter (used 88-92 indifferent models, maybe also on the GSX-F, I think in the US its also called "Katana") will fit to the old GS-engine witthout bigger problems. I cant tell exactly for the bigger ones. and the older ones (85-88) I would not use...

Greets
Flo

 

[scotty]

welcome Flo--i was hoping that dereck would leave the carbs stock except for the main het for the initial test and then go from there if the plugs read poorly

 

[Anonymous]

Hey, I'm learning as I go .
I have gone back to the stock 32.5 pilots, mikuni 130 mains and 1.3mm shim in the needle. The method to my madness was that I would rather start out a little rich and work my way back rather than starting out lean.

Either way, I picked up the new intake boots tonight and will hopefully get back to leak free tuning tomorrow.

FLO: So it seems to run well in the midrange, on the stock needle? Are those mikuni 142 mains or dynojet?
I appreciate the starting point and help from all involved. I will post an update tomorow.

Derrick

 

[Flo]

To my big surprise it seems to run great in the mid range but only the o2sensor tells the real shocking truth... I really wonder about this because with my former GS1150 carbs I put the needles one or even two steps higher than original when changing to K+Ns... I cant tell you if the pre-owner had done some changings (carbs laid in shelf for maybe 3 years... came to me from ebay) but at least there was no dynojet installed. I just jetted them according to my experience and the first try was a really nice run! And then the weather became ugly...
the 142.5 jets are original Mikunis, as I heard a lot of bad reputation about the Dynojet-stuff and the orig parts are quite cheap... and until now I was able to get appropiate results with Mikuni parts...
A tip from me to all customizers out there: get an o2-sensor from junk yard and build yourself or buy from K+N or somewhere else an o2-meter. It REALLY pays and will cost you <20,- bucks if diy. An wideband o2 will bring you even more far but is not absolutely necessary and more costly...
Regards
Flo

 

[scotty]

Do you have an O2 sensor mounted in head pipe??

 

[Flo]

I welded in a thread in the connector pipe between header and muffler. Directly behind the 4-1 collector.

 

[Anonymous]

Project update:
Got everything up and running (finally), looks like I had a flaky plug wire/connection that happened to be temp sensetive, it really confused my carb tuning process.
whith that fixed, carbs synced and jetting : 32.5 pilots, 130 mains, and 0.5 mm shim under the needle, It idles like a champ.
Went for a round the block ride and WHHHEEEEEE...HHAAA....the difference is amazing, pulls well and smooth from idle up, throttle response is crisp and better than ever. In first and second gear, comes on even harder at 6500 rpm.
Getting just a hint of popping on decel, but very little. I think I may need to eventually go up on the mains, but I will not know till I can go for a longer ride and get a read on my plugs.
I am still using the pods from my old carbs( with an adapter) and the inside diameter may be providing enough restriction that the 130 mains are big enough. I think that the oval pods have a much bigger inside cross-section.

But it can be done, and so far it runs hard.

Ps. be careful around the plastic caps, particularly the vacuum nipples, it does not take much to snap one off, like by dropping a socket...


Later,
Derrick

 

[pano]

Thanks for the update.

I am looking forward to getting mine on but I got to finish up the few other things on my plate. As soon as I do I will post.

Thanks

 

[Anonymous]

well, after a longer ride today, still runs pretty well, after it really warms up the idle gets a little sporadic, and the plugs are lookin a little lean. I will richen the idel mixture a little and see how that goes. If tha does not fix I will go after the needles and maybe a main jet. I may have to buy a Jet kit after all, just to get the adjustable needles.
I want to re emphasize that the throttle return action is very light, I had a littel friction in my cable and it was enough to hang the revs during shifts.
I replaced the 1100E cable with the newer Katana one (took a little modification on the handle bar side) and that seems to fix the problem. The newer cable seems to have a heavier sheath, less likely to kink.

It's about the journey right?.......right?......

Derrick

 

[Flo]

Update

Update

stock GS1100engine, 36 GSXR-carbs with 142,5 Mikuni main jets, other orig GSXR-setup, K+N dual filters, Laser 4-1 full exhaust street legal, a bit more ignition advance

I just had a longer ride this weekend, having time to watch the O2-meter. Setup works really nice! Maybe at top I could get one step bigger (145 or 147,5 as I am very clos to LAmbda 1, should be more to 0,9... 0,8) for more hp but it runs nearly perfect, very smooth and always a bit on the fat side according to measuring

 

[Anonymous]

well, after a longer ride today, still runs pretty well, after it really warms up the idle gets a little sporadic, and the plugs are lookin a little lean. I will richen the idel mixture a little and see how that goes. If tha does not fix I will go after the needles and maybe a main jet. I may have to buy a Jet kit after all, just to get the adjustable needles.
I want to re emphasize that the throttle return action is very light, I had a littel friction in my cable and it was enough to hang the revs during shifts.
I replaced the 1100E cable with the newer Katana one (took a little modification on the handle bar side) and that seems to fix the problem. The newer cable seems to have a heavier sheath, less likely to kink.

It's about the journey right?.......right?......

Derrick

You may want to think about increasing the return spring. A different cable is giving a false sense of security.

 

[pano]

I am finally starting to take a look at installing the GSXR carbs and want to make sure I set these up right. can you guys correct me if I am wrong.

It looks as though I have a dual fuel feed, one to the left pair and one to the right pair.

Above the dual feeds I have my vent hoses one for each pair

That seems clear but here is where it gets fuzzy, on top of the carbs I have rubber caps on carbs 3 and 4 and on carbs 1 and 2 the caps are missing. Am I missing the cap for carb 1 and carb 2 connects to the vacuum port on the petcock?

If using a Pingle without vacuum do I cap off all 4 of the carbs on top?

Thanks

 

[RacingJake]

Your right, if not using the vacuum petcock then just cap them off.