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New Engine ran well and now is un-driveable


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Finally got to drive my winter project.

Engine is stock strock, woods port, w/ 28mm Keihin carbs. I dont remember the exact size of the main, my first bike with Keihin carbs, but it was around 158 with a 50 pilot, air screw 1.5 out, JJH needles. Ran great for 3 hours or so. Only issue is it was puking tranny fluid out of the front vent. Figured out the rear vent was clogged and that solved that issue. I filled it up with gas, mixed rich at 24:1 and has not ran right since. 

With the new gas it would only run with the choke on. Drained the gas, put it new gas mixed at 32:1, cleaned the carbs, at least 10 times now, and now it seems rich. Did a leak down test held 6 lbs for 6mins. I did a half ass compression test, 100 in each side, will get a better one tomorrow but cant imagine it is an issue in the top end.

Reeds seem good, besides being caked with oil when i took them out after the rich gas. They were new with the engine, no cracks and closed and held when I tried to suck through them. 

To sum up bike went from running great to now i cant even drive it. Will start, wont idle, smokes a lot. I put new plugs in also. I moved to main down to a 148 and didnt seem to make much of a difference. Adjusted the floats and helped a little. 

With the bike running, if i turn the fuel off, as it is running out of fuel it will run well for a few seconds before it dies.

Any ideas or stupid things I am missing

Ruled out all electrical. Swapped brand new OEM CDI, Coil from working bike, and stator tested out.

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How long between good 3hr. Run & won't run?

Are you sure theyre genuine Keihin carb's ?

there's ALOT of fakes out there.

my keihins got clogged with oil, alot easier than stock carb's.

only thing i can think of is fuel vent, but it sounds like youre to rich, as it is.

 

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Or too much fuel. Flooding out. Reeds are covered in oil? Air tube/choke clogged. Compressed air through circuits upon one of the six cleanings without remembering what size jets?


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Float height? Not sure what spec is but you mentioned it helped. Really seems like a rich condition as it ran better as the bowls emptied.  

Keep in mind as you use less oil in the premix you are richening your air/fuel ratio as well. 

Will it Rev out if you take the pipes off and run it briefly?

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How long between good 3hr. Run & won't run?
Are you sure theyre genuine Keihin carb's ?
there's ALOT of fakes out there.
my keihins got clogged with oil, alot easier than stock carb's.
only thing i can think of is fuel vent, but it sounds like youre to rich, as it is.
 
It sat overnight between running well and not. They are genuine Keihin carbs. I am pretty sure they did get clogged with oil, would only run on choke, and by run I mean start but not drive able. I cleaned them out well, blew out everything with compressed air and now it is super rich. Would taking the gas from 24:1 to 32:1 really make it run that much richer?

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Technically it runs leaner but... fatter oil wise. Shake the shit out of the quad, to stir up oil , & pull hose to get rid of oily mixture @ bottom of tank.  tip it on its grab bar, to see if fuel runs out of pipes. If it'll run, after warming it up, rev the shit out of it, while pulling choke on & off. Otherwise re- clean carbs?

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Tried all that no luck. I had the exhaust off for the leak down test. Right pipe had a little oil but the left was wet, left a puddle where I had it hanging. Cleaned the carbs again, this time in a ultrasonic cleaner. Put in 48 pilots and 148 mains. Left side loads up and shoots oil out of the exhaust. I set the float height to factory spec of 19mm from casting to top of float from when it closes. My first time working with Keihin carbs. Anything I am missing? They are 28mm flatside carbs

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Youre sure theyre not knock offs? or reeds Corners 90° or cutoff?? Still have OG's
Cylinders?... ported?

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What do you mean by corners 90 or cutoff?


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