theo547
Scoot Enthusiast
Posts: 497
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Post by theo547 on May 30, 2011 13:39:54 GMT -5
ok so i installed a bbk using this websites directions - engine seems to idle fine, but when i take it out it only goes 30 mph wont rev past 6.5k rpms ...
Installed a 90 main jet and drilled a few 1 inch holes in my air box so i think its getting enough air...
Pervious to the install i could get the scooter up to 50mph at about 8.2k rpms...
seems like its almost not "shifting" to 3rd gear or something.
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Post by 90GTVert on May 30, 2011 14:26:40 GMT -5
:welcome:
The lack of revs could be a carb tuning issue or a CVT issue. I'd start with the carb. Take a look at the spark plug. Is it wet or dry? If wet, try dropping jet size. If dry, try a larger jet.
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theo547
Scoot Enthusiast
Posts: 497
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Post by theo547 on May 30, 2011 15:26:50 GMT -5
Do you think an exhaust leak could cause this? My springs are lose... Just found this out.
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theo547
Scoot Enthusiast
Posts: 497
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Post by theo547 on May 30, 2011 19:16:13 GMT -5
Ok got new springs... No more leaky exhaust.
I don't think this is a carn issue.... Any thoughts if this could just be it needing new rollers?
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Post by Thebatman on May 30, 2011 19:20:19 GMT -5
It could be in the cvt.. Time for an inspection of the cvt....
Maybe the rollers are way heavy now?
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theo547
Scoot Enthusiast
Posts: 497
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Post by theo547 on May 30, 2011 22:39:09 GMT -5
To answer your question Vert - it is running rich right now.
im pretty sure the problem is either the exhaust or something in the cvt is messed up.
The exhaust is the stock keeway matrix 50 expansion pipe with a aftermarket muffler on the end.
it has a much deeper sound to it with the new kit.
runs very smooth but, has no toped end power. 6k rpms seems to be its max right now.
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Post by 90GTVert on May 30, 2011 22:42:58 GMT -5
If it's real rich it won't wanna rev. You should be seeing wet plugs if it's that rich though. If you suspect the CVT, inspect and clean the components. Swap to lighter rollers to try to get the revs up if necessary.
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theo547
Scoot Enthusiast
Posts: 497
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Post by theo547 on May 31, 2011 13:35:17 GMT -5
Hmmm... If its running wet is my jet to high?
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Post by drawkward on May 31, 2011 14:17:56 GMT -5
Running wet means there is excess fuel not being burnt - excess fuel is running really rich.
Your stock pipe is likely not a true expansion chamber.
I think the.problem is a combination of poor jetting and CVT tuning.
I run an 85 in mine with Leo Vince ZX, stock filter (no snorkel), and 47mm bore kit. About 100 ft elevation maximum.
Can we get a picture of the plug if possible.
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theo547
Scoot Enthusiast
Posts: 497
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Post by theo547 on Jun 1, 2011 11:22:52 GMT -5
ok updates:
1. got new air filter in the mail - free flow type
2. installed 70 jet and lowered needle to the bottom (70 is the only other jet i have currently.
3. Installed 5gram weights
4. Ran a compression test on the cylinder - was at about 110psi with the auto start and 125ish when kick starting.
Plug is now actually running just a hair on the rich side - it has that coffee brown look its supposed to have. i will post pics if you want.
Though it is running smoother at this point Scooter is still not going over 30mph or 6.5k rpms
Im starting to think this is completely an exhaust issue.
Edit: a friend thinks its in the cvt . I'm going to record a video of it and post. I'm getting somewhat frustrated : P
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Post by 90GTVert on Jun 1, 2011 12:27:18 GMT -5
The exhaust shouldn't restrict it to 30MPH and 6500RPM unless theres a restrictor washer in the header and then it should have been restricting it with the last setup. The CDI can't be the issue if it was revving higher and going faster before. 125psi is acceptable and should have you capable of greater than 30MPH. So if you believe the carb is straight it's probably the CVT then. Pop the cover off and start inspecting.
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theo547
Scoot Enthusiast
Posts: 497
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Post by theo547 on Jun 1, 2011 21:26:06 GMT -5
ok finally got some time to get this thing running and took it out for a spin. Reinstalled the 70 main and totally richened up the needle. ran pretty good on the stand got the RPM's up to 8k ---- PROGRESS tried riding... nothing bogged down when i tried rev it. Re-installed 90 main jet and totally leaned the needle. Didnt spend alot of time playing with it on the stand and took it out for a ride. Ok on a very long stretch it will not exceed 7.2 rpms got it up to about 42 mph. i can tell the power the new engine brings to the table, but the top end it totally not there. when i have it above 6.5 and let the throttle off about 1\8th it seems like it re-adjusts and regains power... but as soon as I hit the throttle there is no power to be found. almost feels like the belt is slipping... im going to have a friend who has worked on these take it for a ride tomorrow let me know what he thinks. Im going to stop making assumptions with this thing. ran into a scooter "Gang" and a guy driving a ruckus (sweet bike lol) suggested that my main jet was too high and i should drop it from a 90 to a 80-85 max also the plug after the run:  IMAG0255 by theo547, on Flickr Updated: (with the 90 main jet and leaned needle) Put it back on the stand and tried reving it... goes to about 7.2 and bogs down..... What do you guys think? |
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Post by 90GTVert on Jun 2, 2011 8:14:44 GMT -5
I'd start trying jets between the 70 and 90. Plug looks OK from what I can see.
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theo547
Scoot Enthusiast
Posts: 497
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Post by theo547 on Jun 2, 2011 15:31:30 GMT -5
after driving it a bit today... i think when i get over 6.5 im hearing what almost sounds like a "ping" ... like the cylinder is loosing sync with the spark... i really could be just hearing things and i havnt changed anything.
Anyone had that happen?
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Post by jmkjr72 on Jun 2, 2011 22:10:16 GMT -5
what plug are you useing you did go 1 or 2 numbers colder right
and where abouts in green bay i actauly live just south of denmark
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