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Discussion Starter #1
Please help!!! Bought an 1100M (1991) model about a month ago, got 2 so-called expert bike shops to check it out.Bike was going fine before they got their Fu*@#ng grubby paws on it. Now getting progresively worse.Everything standard except for 4in1 V&H with yoshi slip on. Problem is in first 20% of throttle opening.Starts fine, but wont idle or run smoothly at small throttle openings. They've bullshitted me enough now, so I started doing some research, and it would appear that the problem is with the pilot circuit. I am now preparing to get my hands dirty and do the thing myself Can anyone give me the standard specs for these carbs ie jet sizes, needle settings etc etc? I am desperate and tired of being ripped of by so-called [email protected]#$ng mechanics.
 

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I guess the most basic if it won't idle properly would be to synch the carbs. Then start fucking with the pilot circuitry.

On mine, with headers and a stock replacement K&N (some years back), it only took a jump from the stock pilot size 40 to 42.5 to clean up the bog at the low end like you describe.

Someone should be able to feed you the stock numbers, then pop up a size.
 

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Discussion Starter #3
Thanx-should get to it in the next few days. I suspect that its the float heights. The first guy told me that he had adjusted everything "nicely",and that it was'nt neccessary to synch them. You should be able to prosecute pricks like that,coz on these bikes fuckwits like him endanger your life.
 

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Discussion Starter #4
Ok done the following
MAIN JET: #125
PILOT JET: #40
FLOAT HEIGHT: 14.7MM
NEEDLE HEIGHT: #3 NOTCH
PILOT SCREW: 2 TURNS OUT
The bike still has same problem. It's not so much a "bog" AS spluttering at partial throttle opening, if you open it fully it goes, it's just if you try to ride slowly. Mileage 20000. Could worn needle's be causing this problem? The only thing that does'nt make sense is that the bike was fine, before they worked on it. i forgot to mention that they changed the head gasket, could valve timing cause this problem? I also neglected to mention that I use the bike at altitude(Johannesburg S.A.).
 

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altitude could definitely be an issue....the 'sputtering' does sound like a rich condition.

what altitude are you at, exactly?
 

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The basic tune-up sounds reasonable, so the only wildcard is determining whether the stumble is rich or lean.

Here are a couple of URLs that may help you in nailing down the problem...

http://www.factorypro.com/tech/carbtun.html

...if you follow that page step-by-step you will be able to find the handle on the symptoms.

There's also...

http://www.factorypro.com/tech/needle_jet_Mikuni.html

...since the problem only started after the "experts"
had their hands on the bike the second URL probably isn't a factor- but since you've got that many miles/km on the needle jets it's probably at least worth a peek.

good luck!

Ed
 

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I'm thinking the same, Jeff- taking 0.040" - 0.060" of needle out of it might very well sharpen the midrange back up... I'd be curious to get a look at the plugs and pipe tip.

Ed
 

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Discussion Starter #9
Thanx guys, getting a dynojet kit, at least the needles etc will be new, it's a hell of a lot cheaper than the stock items. Ed, when you say take some needle out of it, do you mean raise/lower the clip settings?
 

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Yep- move the clip up closer to the blunt end of the needle. The Mikuni, FP, DJ, and Holeshot needles I have here all have the clip slots on 1.0mm [0.040"] centers.

Based on the altitude in Jo'burg I'd think you can take at least one full slot out of it; you may also find it beneficial to back off on main jet a step or two, depending on what the plugs tell you... those 125's would be about right for me here at 250m above sea level, so it wouldn't surprise me if you end up closer to 120's.

Ed

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Discussion Starter #12
Thanx-weekend coming up. A couple of sixpacks etc to "lean" out my concentration and Hopefully by monday we will know a bit more one way or the other. What should the stock horsepower be +-? Would it be worth investing in some flatslides?Do these bikes have a problem with oil seepage at the head gasket?
 

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hmmmm.....certain european spec 1100's of that era were restricted by suzuki......the stock canisters had much smaller outlets (not an issue on your bike if it has an aftermarket exhaust), as well as artificial 'webbing' in the intake boots which restrict flow.

you might want to check to see that yours has been desrestricted.....if not, it's just a matter of cutting away the webbing with a knife, and smoothing out the rough edges with some sandpaper. obviously, do this with the intake boots off the motor.


stock and derestricted, these euro spec 1100's are good for around 125-130 horses at the rear wheel.

unfortunately, at your altitude, expect a substantial drop in power...you'll probably lose somewhere around 20 horsepower, at least....


these motors like to weep oil from the valve cover bolts and past the valve cover gasket, in my experience anyway....

replacing the oil seals underneath the valve cover bolts can help, at least for a while. i got so sick of having oil weeping from that area that i used to use high temp rtv underneath the bolts......oil leaks solved.


[ 11-08-2001: Message edited by: jeff ]</p>
 

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Discussion Starter #14
The needle,s are totally fu%$#ed. The bottom of the inside of the plastic slides are not flat. The one side has about a 1.5 mm raised step in the plastic. This causes the teflon/plastic washers under the needle circlip to be at an angle,causing the needles to enter the emulsion tube at an angle. i can not believe this is part of the design(makes no sense). is it true that the inner carbs have different jet sizes to the oute? If so is it mains only, or pilots as well
I am thinking of junking these carbs, what would be the best replacements. I am thinking that as I am altitude allready, smaller carbs(36 mm flatslides) would be a better option.I suspect I am going to have shit in future with these cv's anyway as the plastic slides running in plastic bodies dont look too kosher to me anyway.
 

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That inside-of-the-slide step isn't unique to your carbs, unfortunately- it's typical of the breed, and no doubt it's a big factor in why these carbs tend to eat needle jets (and non-hardcoated needles) so quickly.

I'm not sure how to quantify <blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>I am thinking that as I am altitude allready, smaller carbs(36 mm flatslides) would be a better option<hr></blockquote> ...on the one hand the smaller carbs do help build torque, on the other the engine needs all the help it can get inhaling a cylinderful at that altitude.

Stagger-jetting the inner pair is also very common- so far I've only seen a step in main jet, with the same-size pilot jet across the rack.

Agreed, if the slides look worn out (running without air filters will do this in quickly) you are probably gonna have a helluva time fighting varying degrees of leakage when you're trying to come up with a livable tuneup.

CV carbs for the o/c engines are cheap and readily available (here in the States, anyway)... hopefully you'll have good luck finding a decent set to work with.

Ed

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Discussion Starter #16
Thanx, what do you call cheap?(our exchange rate is worth shit 3RD WORLD DONTCHA KNOW).What about fuel injection? A dynojet kit costs about 30% of the average wage around here(average fair wage about $600 a month). Can one buy the needles and emulsion tubes loose(mailorder maybe). I changed my mind about the dynojet kit,kinda pointless if its gonna wear out so quickly, I did grind the washers smaller, so the step isn't a problem anymore, and the needles are moving nicely now, It's allready improved, but you are right I have to get new ones(needles etc). I paid equivalent of $2800 for the bike (supposed to be my toy), so huge capital investment not considered at this stage.
 

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lol Yeah, I guess "cheap" is a somewhat relative term... here in the US a set of 36-38-40mm CV's in nice shape will fetch around USD $250 - $275, whereas a set of RS38's in so-so condition will set ya back USD $350 - $375...

Looking at my trusty online currency exchange-rate calculator http://www.xe.com/ucc/ I get an idea of what you're up against... US$250 = 2,405 Rand as of this morning


fwiw here's one resource for Mikuni needle jets... http://www.factorypro.com/tech/needle_jet_Mikuni.html ...hopefully you'll have a local resource so you don't get stuck with around-the-world shipping cost.

Ed

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Discussion Starter #18
upside for you guys is, you can come and eat in a good restaurant and get pissed for $10 so back to carb. You say inner mains about 1 size bigger than outers?
 

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<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>You say inner mains about 1 size bigger than outers?<hr></blockquote>

That's pretty commonly reported, although I don't run my own stuff that way... I just run the mains straight across but sometimes run a little more needle in 2 and 3 to keep them a whisker cooler.

Interestingly, some of the OEM setups for w/c 1100's were set up the other way around, i.e., 127.5's outside and 125's in the center pair.

Ed
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Discussion Starter #20
Back again, a guy who used to be a dynojet dealer found some odds and ends that he thinks may be for my bike. He's given me some needles and emulsion tubes.However, the needles are not the same length as the stock item, but maybe they go with the emulsion tubes he's given me?? I dont want to strip off the carbs again to take out my tubes for nothing. Does anyone know if the dynojet needles are shorter than stock needles???
 
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