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Post by 190mech on Jun 21, 2015 14:59:10 GMT -5
OK,printer paper is .0025" thick,stack 3 sheets together and that'll give you .0075",thats about what your ring gap should be.. Be sure to clean all the carbon from the ring grooves before installing the new ones.Hand hone the cylinder as I posted a while back so the rings can seat into the cylinder..
Muffler repack,remove the silencer mount strap,remove the (3) 10mm nuts on the rear of the silencer,remove it from the pipe,tap the 3 mount studs gently and the silencer should come apart.Clean the mess up and repack it..
Flexible steel cable called 'wire rope' sold at hardware stores is the tool for pipe cleaning,get 3 feet of 3/16" wire rope and chuck it in an electric drill,feed it into the pipe,then run the drill.It flaps around inside the pipe and breaks the funk loose,may take a few sessions to knock it all out.. Good Luck!!
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Post by sai on Jun 21, 2015 15:31:44 GMT -5
Rode the bike 12 miles just now, power came back but I can feel it's not perfect yet.
1. Could rollers which are a little flat here and there affect the power and mph? The bike doesn't sound as muffled anymore, but still a little.
2. Update: spoke too soon. There's still no difference in power. Feels weak on and off. Sometimes top speed is 35 , sometimes 45. If I stop on the side road and rev it out at full throttle and begin riding again again, it comes back but then loses the power again the longer I ride
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Post by 90GTVert on Jun 22, 2015 8:06:07 GMT -5
Flat spotted rollers certainly won't help anything. Sometimes they really have a negative impact and other times their effect hasn't been that bad. Best to replace them if the flat spots are anything more than minor. Your compression should still be 130, or possibly just a touch lower, after removing the carbon. More silencer info : 49ccscoot.proboards.com/thread/373/repack-silencer
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Post by sai on Jun 22, 2015 10:52:37 GMT -5
What about the richness and also the weird bassy / low noise that the bike is making? Normally the Leo vince makes an aggressive high pitch noise, but it's been really subdued since all this problem arise
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Post by 190mech on Jun 22, 2015 11:30:32 GMT -5
Maybe the muffler IS clogged,did you open it up yet?
PS, remove the muffler(silencer),then give it a test ride..Yep it'll be loud,but you will know if its the muffler that way..
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Post by sai on Jun 22, 2015 12:55:52 GMT -5
I can see the opening from the exhaust to the muffler all into the end of the muffler's pipe and I see light... I did clean off some carbon too.
But I'll give it a test ride later without it. Also waiting for new rollers from Treatland to come.
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Post by sai on Jun 23, 2015 12:00:52 GMT -5
1. Took out the muffler and drenched the exhaust in brake and carb cleaner... emptied almost 2 cans and used a wire rope on a hand drill also.
2. Sprayed PB blaster into the variator since the part that looks like a cylinder seems to not rotate smoothly and got slightly stuck to the variator system.
3. Checked rollers... I feel that they aren't badly flat (but then I don't know if they are or not).
No improvement, still slow and losing power...
any other suggestions?
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Post by sai on Jun 23, 2015 16:14:30 GMT -5
Update...
Spark plug is wet black and compression is now slightly below 120psi...
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Post by scooterpimp on Jun 23, 2015 19:21:42 GMT -5
Did ya put on new rings / hone cyl. Before reinstalling?
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Post by sai on Jun 23, 2015 21:04:17 GMT -5
I just bought some malossi rings (don't have a honer) . So far the power is back to a degree I think the rollers and going back from 89 to 91 main jet will fix that...
Will test the compression again tomorrow... I don't own one since it's rather expensive.
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Post by sai on Jun 23, 2015 21:05:44 GMT -5
The dark sides of the piston looks like ring leakage is going on..With 7000 miles on it, a new piston,ring set,piston pin,and pin bearing with new gaskets would get it back in good order.A cheap fix might be just rings and gaskets.+ decarbonize as Brent said.. I just bought and replaced the 2 rings. Seems to have fixed it 90% . How did you know it's the ring that's giving out?
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Post by Elektrey on Jun 23, 2015 21:14:34 GMT -5
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Post by niz76 on Jun 23, 2015 21:15:29 GMT -5
The dark sides of the piston looks like ring leakage is going on..With 7000 miles on it, a new piston,ring set,piston pin,and pin bearing with new gaskets would get it back in good order.A cheap fix might be just rings and gaskets.+ decarbonize as Brent said.. I just bought and replaced the 2 rings. Seems to have fixed it 90% . How did you know it's the ring that's giving out? 190mech Knowz all!.... (The darkening of the piston "under" or "past" the rings is evidence of the ignited charge (exploding fuel) is escaping past the rings which- in a perfect world- should seal tightly against the cylinder wall and not let anything past it- and making the piston dark aka 'blow by'... new rings- 'tighter' fit- less charge escaping past them- voila! better compression and a stronger running engine!) EDIT/ADD ON: The explosion that results from the compressed fuel being ignited by your spark plug spark is what pushes down the piston which turns the crank which eventually is transferred to the tires... If the rings are not sealing against the cylinder walls as good as they used to, some of that explosion is escaping by the rings/cylinder wall seal and is just wasted. Imagine spitting a spit wad out of a straw... ok, now imagine shooting the same sized spitwad out of a larger straw (the spitwad is now loose in the straw). You blow the same amount of air, but the spitwad isn't sealed tightly against the inside of the straw so 1/2 the air just escapes by and is wasted! Now think of the piston as the spitwad with the cylinder being the straw and the air blown as the explosion of fuel... too much leakage = weak engine! (low compression). BTW- your scoot may actually pick up a little more power as you ride more and 'seat' (seal) the new rings against the cylinder wall...
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Post by 190mech on Jun 23, 2015 21:20:01 GMT -5
As I stated,the sides of the piston are dark from blowby during combustion,they should be silver(as the rest of the piston) or a light brown..7000 miles is a lot of piston strokes and rings do wear out even with the best materials and oils.Didnt I post in one of your threads about 'hand honing' a cylinder?I hope you did that during the ring install..
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Post by niz76 on Jun 23, 2015 21:42:01 GMT -5
Yes 190mech! That post was a friggin golden nugget! That was probably almost a year ago now- It was a post in one of Sai's threads where you showed us a pic of a PVC tube (representing a cylinder) where u drew arrows to show the direction of the sandpaper to make your own "hand honed" crosshatches! I saw that post while I was a newb (well I still am- relatively speaking!) and have used that little trick so many times over now- it's the reason I still don't own a ball hone it works so well!- I have even had members PM me and ask about this "hand hone" post so they could do it themselves. Shoot- if it isn't already in the Tech Library, it should be!
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