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Discussion Starter · #1 ·
I recently rejetted my bike and replaced some bowl gaskets and a fuel filter, etc... and when I got the bike it ran fine, just lean. Now it kind of sounds like its choked all the time and occasionally sputters at the low end. As I rip the throttle open it goes away at the top end. I checked for vacuum leaks at the intake rubbers and at the carb bodies and did not find any large leak.Its got keihin carbs, 122.5 jets i just installed. Is there something I missed in rejettin that would cause a low end stumble? Please help I am bikeless until she runs good again
Thanks

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need info....was this done on a dyno? did YOU install the kit or did a shop? anyone can install a kit,but tuning the bike after is a different story. The needles need to be adjusted as with the jets.....this takes a while....

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Try bumpin the main jet size down one increment. Thats the problem I had . It was just runnin too rich.

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Discussion Starter · #4 ·
I talked to my boss at work and he said I should lower the needles in the top of the carb and that I probably wouldn't have to change that long, low speed jet. Is this right? Should I fiddle with the needles? I really don't have the money to send it to a dyno or a shop so I want to do this myself. Please, some more direction.
Trixta, I will try bumping down a jet size and we'll see what happens.
Thanks

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[This message has been edited by kdj67f (edited 04-04-2001).]
 

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Discussion Starter · #5 ·
I installed the jets, I replaced a broken float and I started at 120 jets and jetted up until it stopped hesitating at throttle tip in and stopped popping under deceleration. the store was out of 123 jets and they had some oddball 122.5 and they seem to be perfect for mixture. The plugs dont change color no matter what I do so I cant tell it's running too rich yet. I did this myself in my garage. I had an idle mixture screw break off in the carb body and i only slightly enlarged the bore getting it out. I know this will be a problem so I am loking for new carbs or bodies to replace it. But turning the screw all the way in yielded no results as to the idle quality. Turning all of them in makes the motor kinda die. I assume that shuts the fuel off when you turn the screws in. The idle setting is right, so it should not be running on the primary circuit. It might be a vacuum leak, I will look at it even further in depth this weekend. I was thinking I should just replace the intake boots (rubber donuts) anyways. The friggin bike is almost 20 YO its only got 16000 miles too. I am running the idle mixture screws at about 1-3/4 turns out (except on the broken one, I run that one damn near tight) Adjusting the needles? help me out. Anything else i missed?

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Discussion Starter · #6 ·
Beeno,
Thanks for the advice brutha. I found out my problem, hopefully. A large piece of something non-disolvable was lodged in the jet and taking the tank off must have dislodged some rust in the tank cause there was mucho red-brown slime in the bowls. I also took apart the carbs and did notsee any method of adjusting the needles as one peerson at my work said. I just need this bike to be reliable enough so that I don't feel bad about selling it, as the profit goes to the gixxer fund (my saving account)
Anyways, thanks.

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Boys, this is not a main jet problem. The only time main jet size is important is at not only wide open throttle, but wide open slide which are two different animals in a CV carb - but that's another story. You said the bike ran good once it gained some revs, but it acted like the choke was on at part throttle and, I assume, at idle. I would concentrate on the cleanliness of all the passages in the carbs (ChemTool works bueno) and on the pilot screws. You said one of them was damaged somehow and you had it screwed all the way in. Fix that ASAP. Meanwhile, warm the bike up and see if the header for that cylinder (with the broken screw port) is running at all or just really poorly by dabbing a bit of water on the header with a wet rag or spray bottle. It may be running on three, although by the knowledge you demostrated in your posts, you've probably already ruled that out. You're also on track looking for air leaks which would cause it run excessively lean at idle (but everywhere else in the rev range, too). While the bike is running, spray some WD-40 (or WD-41, whatever it takes) on the carb boots one at a time. If the idle rpm changes, viola! you've found your culprit.

Best, Beeno.

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dkj67f,
You are welcome, mi amigo. It is also quite honorable of you to try to get the bike to tiptop shape prior to selling it. Good on ya.
I read the crotchety Cycle Doc over on 2wf.com every month, and it is amazing how much stuff can be fixed by cleaning carbs, but people (not you) are too intimidated by mechanical stuff to take it apart and just do it.

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Discussion Starter · #9 ·
I love learning the hard way. I knew nothing about cars until I took the engine in my fairlane apart. Next thing I know I am setting up rear end and building transmissions. Same way with the bike. I started out knowing nothing specific about that POS and look at me now, I am a certified tuner ( hahahaha
)
Thanks though, for the input.

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