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Post by newbscootdude on Nov 15, 2014 11:35:17 GMT -5
hey guys so this problem is repeatable and it only happens at rpms over 7k its kind of hard to describe but the easiest description i can come up with is the scoot looses all power at high rpms and will bog when i give it gas when this happens, i have to go down to idle (if it doesnt stall) for a couple secs then the problem fixes itself. it doesnt feel like anything major is happening (like nothing is breaking) if you guys want i can probably make a video of it happening if you guys want to hear whats going on. and btw the 115 jet isnt rich did a spark plug chop and the color on the base of the ceramic is a lite smoke/tan color however i do get pops when letting off the gas at rpms over 6k which im sure is a lean condition so that could mean i just need to richen up the a/f ratio? Maybe vacuum loss is a factor. Straight line your fuel line To the Carb and try that. Don't forget the cutoff valve... its already a straight line gas line i think the gas tank is under the carb so it has the petcock tho. noticed a lot of oil coming out from around either my carb manifold boot or the cam chain tightener. I figured it couldnt be the carb manifold tho theres no oil going through there its a 4 stroke but do u think maybe that could be a problem as well? also i have a friend who fixes up stuff off craigs list then sells them so hes pretty much a mechanic and he told me to run my intake valve at .04 and exhaust at .05 i remember reading a long time ago they should both be at .03 do you guys think i should tighten the valves up to .03? |
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Post by newbscootdude on Nov 7, 2014 10:18:01 GMT -5
hey guys so this problem is repeatable and it only happens at rpms over 7k its kind of hard to describe but the easiest description i can come up with is the scoot looses all power at high rpms and will bog when i give it gas when this happens, i have to go down to idle (if it doesnt stall) for a couple secs then the problem fixes itself. it doesnt feel like anything major is happening (like nothing is breaking) if you guys want i can probably make a video of it happening if you guys want to hear whats going on.
and btw the 115 jet isnt rich did a spark plug chop and the color on the base of the ceramic is a lite smoke/tan color however i do get pops when letting off the gas at rpms over 6k which im sure is a lean condition so that could mean i just need to richen up the a/f ratio?
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Post by newbscootdude on Oct 24, 2014 14:35:19 GMT -5
i would try to tap it with the original size bolt see if that works if not go up one size that will definitely work youll just have two different size bolts.. if you try to glue it next time you want to take it off itll be a getting out and youll have to clean the hole out then reglue it and thats no fun. also you would have to get some really high temp glue otherwise itll break down on you at some point when your riding and that wont be good either.
my advice do it the right way.
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Post by newbscootdude on Oct 23, 2014 13:14:57 GMT -5
the only thing i can chime in on is the battery. check the label on youre old battery and see if it said something like 12v8ah or 12v4ah your basically looking for the number in front of the ah then compare that number with the number on your new batter if its lower than your original thats why you cant get very many cranks out of it (i would be assuming you got more from old battery) i made that mistake myself my scoot takes a 12v8ah battery and just bought one that said "fits most 50cc scooters" and when i got it its a 12v 3ah i wouldnt even crank my bike over once...
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Post by newbscootdude on Oct 23, 2014 13:07:34 GMT -5
so i bought a variator weight tuning set i currently have 3, 6 grams and 3 7 grams wich would 6.5g weights in my scoot atm (i felt the 8gs was too heavy) i have better off the line revs hits about 6-6.5k revs then goes down to about 4 once the variator opens up then climbs up pretty decently. with the 8gs off the line revs was like 5k (just under torque curve) and would drop to like 3k and it would took awhile to climb up in speed and rpms but i noticed i was getting a higher top end speed with lower revs like 40mph@5.5k rpms and 45mph@6-6.2k rpms. i know its a give and take kinda thing with variator wieghts and i was completely excepting this, but i guess what im trying to ask would be is what is the red line on an 80cc bbk? torgue curve i believe ends at 7.5krpms so i would be assuming nothing over that? (i saw a chart a long time about torgue curves on bbks i could be wrong so kinda why im asking as well)
so im currently 'cruising' (3/4 throttle) at 40 with 6-6.3k rpms 45@6.5-6.8
i can really feel the torque kick in at 6k rpms i can cruise at 40 with a little over half throttle which is right about 6k rpm range. i feel like these 6.5g wieghts is much better because im getting up to speed a lot faster but with out going to high on the top end rpm range.
so once again feel free to just chime in with mph@rpms! preferably only the 80cc bbk guys/gals out there
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wierd shake.
by: newbscootdude - Oct 22, 2014 14:31:16 GMT -5
Post by newbscootdude on Oct 22, 2014 14:31:16 GMT -5
more like it was 3/4s of the way down in the clutch pulley. i knew it was wrong from the start but like i said previously scrappy dog scooters insisted it was the right size belt..... other than that everything is running great now still doing break just did the first oil change on her the flake in the oil wasnt really bad so thats great !  the only thing is im gonna try some 7g weights i feel like the 8gs are a little heavy as right on take off once the cvt reaches final gear ratio its really boggy but i was cruising 45mphs (scoot spedo) at just around 6-6.3k rpms it felt like it had way more to give just didnt want to push the top end with it still being in break in. for future reference how hard is it to put taller final gears in? i think the only thing i would have left to do would be get a better cam and taller final gears. |
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wierd shake.
by: newbscootdude - Oct 22, 2014 13:19:09 GMT -5
Post by newbscootdude on Oct 22, 2014 13:19:09 GMT -5
PROBLEM IS FIXED!!!
got a new bigger 742 belt i believe was the size and its perfect! old belt size was 692 way too small ty for all the help tho guys really appreciate it!
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wierd shake.
by: newbscootdude - Oct 22, 2014 8:05:50 GMT -5
Post by newbscootdude on Oct 22, 2014 8:05:50 GMT -5
There is also the possibility that the exposed Kevlar fibers have dug grooves in the variator drive faces which will cause vabrations at various rpm as the belt passes over them. This can be amplified by a belt that has hardened. At walking speeds do you get a mild up and down sensation when rolling along? That would indicate a out of round tire that is unsafe to ride on due to the cord rotting out and starting to herniate. Check this before going too crazy tearing things apart. no i really dont get anything like that while walking it but ill check again to make sure. ill inspect the variator face make sure its got no grooves in it. could the same thing happen to the clutch side of the cvt? (again idk what thats called) i was looking at the tire while letting it slowly turn to look for bumbs and flat spots i did not see anything. |
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wierd shake.
by: newbscootdude - Oct 21, 2014 18:31:56 GMT -5
Post by newbscootdude on Oct 21, 2014 18:31:56 GMT -5
I agree with rockynv, the belt is probably out of round from sitting in one position. A few miles on her will probably clear it up if this is the case. If the vibration continues after 20-30 miles, I would continue to hunt for a cause. drove it around for about an hour hour and a half doing a swerving/bobbing motion the whole time to heat the tires up but to no avail... i think i may have located where the shake is coming from tho! i feel its either the clutch or the rear tire. im going to take the clutch off and give it a look at and take some pictures maybe you guys will spot something. if that comes up as a dead end my job has a tire balancing machine so ill through it on there see if that helps. i was able to get the scooter up to around 5-5.7k rpms but then the shake got pretty violent. towards the end of my ride i was giving it full throttle for a little just to see what happens for a sec or two and whatever is shaking is causing almost total power loss. starting out is just fine a little shake at 3k rpms smooths out a little inbetween the 3.5-5k rpm range but once it hits 5k the shake becomes really bad and all power is lost i dont know how else to describe it but is it possible for the clutch to shake and lose contact with the clutch bell (or whatever it contacts with not sure tbh)? |
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Post by newbscootdude on Oct 21, 2014 18:01:41 GMT -5
i had that sounds happen to me like you said it sounds like it coming from the muffler right? what i did was take the muffler off inspect the gasket make sure thats good then i tightened everything back up and the sounds went away. im pretty sure the bolts i had in there (stock studs broke) loosened up and i didnt notice hopefully its something easy like that for you as well. it could also be a backfire into your carb and the sound is coming out of ur air filter not sure what to do about that one im sure someone will chime in on that tho. I put up a video. I think it's a backfire but it doesn't sound like when my scooter backfires. In the video it sounds like a pop, but in real life it's more 3 dimensional, like a fast high pitched sound followed by a whoosh. Still, I'm now thinking backfire. Weird sounding backfire. did you try inspecting the studs to your exhaust if its leaking it can cause backfires like that i had the exact same problem i heard it in the video sounded identical to what was happening to me. |
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Post by newbscootdude on Oct 21, 2014 13:08:41 GMT -5
i had that sounds happen to me like you said it sounds like it coming from the muffler right? what i did was take the muffler off inspect the gasket make sure thats good then i tightened everything back up and the sounds went away. im pretty sure the bolts i had in there (stock studs broke) loosened up and i didnt notice hopefully its something easy like that for you as well. it could also be a backfire into your carb and the sound is coming out of ur air filter not sure what to do about that one im sure someone will chime in on that tho.
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wierd shake.
by: newbscootdude - Oct 21, 2014 11:55:38 GMT -5
Post by newbscootdude on Oct 21, 2014 11:55:38 GMT -5
oh and alleyoop i couldnt find the stock cdi to try that out  heres the video |
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wierd shake.
by: newbscootdude - Oct 21, 2014 11:28:33 GMT -5
Post by newbscootdude on Oct 21, 2014 11:28:33 GMT -5
ok im just scared to ride it bc the vibration is that bad. ill start her up and take the cvt cover off and give it a look. will i notice any bends while im doing this? also the belt i got from scrappy dog scooters is a bando belt i believe its kevlar. i was looking at it the other night and noticed that a string was peeling off the side of the belt just under the top band and just above the grooves in the belt where the band and groves meet and this is a brand new belt maybe has 20 miles on it. when i got the belt it was supper hard to put it on and i feel like the belt is way to small for the cvt even with the clutch pulled all the way out it was a pain in the arse to get it on. when i called them they told me that its the right size i have a long case (9 bolts and 12 inch tire) i havent inspected the belt while its running yet so im gonna go do that now and see what it looks like while its running but again im not revving the engine anything past 4k rpms bc the shake gets too bad for my comfort so idk if itll go out to that final gear ratio at that low rpms. would a flat spot in a tire cause it to shake bad while its on the center stand bc the tire is out of round and off balance? ill let the bike idle for say an hour and see if the belt straightens out.
if i do all this and the shake is still there i know im gonna have to take her apart but what would i even be looking for? im kinda worried its something to do with the crank.....
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wierd shake.
by: newbscootdude - Oct 19, 2014 13:13:57 GMT -5
Post by newbscootdude on Oct 19, 2014 13:13:57 GMT -5
i think i have the stock one laying around some where ill really have to look for it ill let you know if i find it and try it.
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wierd shake.
by: newbscootdude - Oct 19, 2014 12:27:49 GMT -5
Post by newbscootdude on Oct 19, 2014 12:27:49 GMT -5
ok cleaned out the carb this morning shes purring like a kitten tyvm alley! now i still have this pretty bad shake at anything over 3k rpms problem to figure out. i really dont want to tear through the engine and start looking for bent stuff without really knowing what im looking for so if anyone could give me some suggestions maybe ways to test without taking the engine apart it would be great! if need be i will take it apart and probably inspect the cam the rockers the valves nothing else really comes to mind so like i said before all suggestions are welcome! i dont know how to take the valves apart so if anyone could post a link to either a video or a manual/schematics with their suggestions that would be much appreciated. i keep forgetting to add in my signature its a 4 stroke.
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(need 112)
