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Need help with my 421 cub


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Hey guys need some help, just got the cub together spent two hours breaking in ,let warm up and cool down and so on.Then took it to the dunes ran great out of gate never rode it hard went to climb a dune and lost my right cylinder,so I replaced plug still nothing then I noticed that the fuel line came apart and soaked my filter so I removed the filter and started still nothing, but the carb was spitting allot of fuel back out of the air intake side of carb any help please I very worried, everything is new got about 4,000 invested in rebuild new tranny 4mil crank,barrnet clutch,36mm carbs,spacers,v3 reeds,cpi inframe,pro des. coolhead 18cc domes on 111 octane,+6 timing,793mo68 wiseco blaster pistons,lighten flywheel.Any suggestions or anybody with simular problems? I forgot to mention it will fire at high rpms but is hard to take off got no power. :ermm:

Edited by J-WELDO
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if your getting gas to back wave thru the carb you most likely have reed problems.

 

will it even idle??

Yes on one cylinder but when I rev it up the other cylinder starts firing but when I let it come back to idle the other cylinder dead again

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are your carbs synced at all.

 

all i know if your getting gas to shoot back thru the carb you have issues.

 

rn brads bike was that way at the dunes wouldnt idle ran like ass. i think he is getting new reeds. i had some vf2 go bad wouldnt idle it would idle high the fall on its ass. motor ran like barely on one jug.

 

i would start that. pull the reeds off and you should see any light. the pedals should be closed completely.

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Yes on one cylinder but when I rev it up the other cylinder starts firing but when I let it come back to idle the other cylinder dead again

You guys think a better set of carbs I have mikunni t36 flatslide with power valves but power valves are closed for now till I break it in fully I was thinking maybey some lectrons

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it's likly your main did a 180 and is now pointing out of carb,i,ve seen this happen quit a few times. take your filter off and make sure it is still pointing into cylinder.

Yes main is fine so thats not it but thanks anyway

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my 421 did that this weekend also i just took my carbs apart and cleaned the hell out of the floats. i think my oil in my tank settled b/c my floats were covered in oil. just an idea i don't know if it will help u and u might have already went through ur carbs. but after i did that it fired up and ran great.

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my 421 did that this weekend also i just took my carbs apart and cleaned the hell out of the floats. i think my oil in my tank settled b/c my floats were covered in oil. just an idea i don't know if it will help u and u might have already went through ur carbs. but after i did that it fired up and ran great.

It was the reed petals.Thanks allot guys rock on shee HQ!! :biggrin:

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