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Post by kavid2013 on Apr 20, 2013 21:21:48 GMT -5
hi, my scooter is Chinese 50cc and I have put the 80cc BBK and it has run 1,200 miles with the bbk on it.
and whenever I go high speed, the engine jerks.
whenever It passes 40 miles per hour it start jerking time to time.
I don't know what it is. could it be the piston ring gap being too small and cylinder being too tight?
it jerks like 3 - 5 second interval constantly whenever I run the scoot over 40miles per hour
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Post by skuttadawg on Apr 20, 2013 22:32:48 GMT -5
Do the RPMs go up or down the the jerk ? What size variator weights ? Did you put on a new belt with a BBK ? Alawys good to start a new engine with new belt . Any two wheeler will get nuts and bolts loose so do a go over to make sure all is snug .
How is the jetting ? Even with all the mods under the sun it will still only do so much and never perform like a crotch rocket
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Post by kavid2013 on Apr 20, 2013 23:01:27 GMT -5
the RPM goes down little bit when the jerk happens and entire scooter is pulled back little too. I didn't change the variator weights from stock one. and haven't changed the belt either. I have changed the jet to #  |
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Post by alleyoop on Apr 20, 2013 23:10:38 GMT -5
Any sounds from the motor, POP, BRAT sounds?
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Post by kavid2013 on Apr 20, 2013 23:16:55 GMT -5
no sound from motor
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Post by alleyoop on Apr 20, 2013 23:31:59 GMT -5
When it happens Back off the throttle just a little 1/4 of an inch and HOLD IT THERE see what it does.
A. If it speeds up it is LEAN, needs more fuel.
B. If it still bucks but THEN Settles down it is RICH.
If backing off just a little doesn't help then it could be electrical.
Do you have a tach on it to see what the RPMS are.
Alleyoop
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Post by kavid2013 on Apr 20, 2013 23:37:45 GMT -5
maybe rich
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Post by alleyoop on Apr 20, 2013 23:40:48 GMT -5
You won't know until you try it. It is an old trick of the trade and it is very accurate if it is one or the other and takes the guessing out of it, then you know which way to go.
It could also be your CDI cutting out may have a rev limiter.
Alleyoop
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Post by justbuggin2 on Apr 20, 2013 23:43:28 GMT -5
DX
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Post by kavid2013 on Apr 20, 2013 23:52:02 GMT -5
I'm thinking it could be the CDI limiting the rev
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Post by alleyoop on Apr 20, 2013 23:57:28 GMT -5
Well get back with any results.
Alleyoop
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Post by spandi on Apr 21, 2013 0:58:54 GMT -5
... and here I thought this thread was about young squids on sport bikes. ;D
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Post by prodigit on Apr 21, 2013 10:52:32 GMT -5
It could also be a bad counter balance.
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Post by skuttadawg on Apr 21, 2013 10:54:09 GMT -5
Did you remove the restricter washer ?
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Post by dyoung1167 on Apr 21, 2013 13:02:04 GMT -5
look for loose connections on your coil dropping some spark as they vibrate.
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..BAD TO THE BONE..
