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Post by Steve B on Aug 26, 2020 13:01:29 GMT -5
Badumts123, Did you ever take the drive belt of and rev it on the kickstand? if not you should do so so because that will tell you whether its restricted or it is the stock port timing. I can tell you one thing for sure 37mph is restricted. By taking off the drive belt you will bypass the clutch bell sensor system.
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Post by badumts123 on Aug 30, 2020 16:55:56 GMT -5
Badumts123, Did you ever take the drive belt of and rev it on the kickstand? if not you should do so so because that will tell you whether its restricted or it is the stock port timing. I can tell you one thing for sure 37mph is restricted. By taking off the drive belt you will bypass the clutch bell sensor system. no i didnt do that but i took out everything in the tranmission up to the crank, theres no sensor for sure. gonna take it to the mechanic who rebuilt it tomorrow. somewhat anxious that he wont be able to fix it since last time i told him theres a limiter he told me "theres no limiter on this mode" and that it was slow due to stock exhaust, hopefully he knows.
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Post by Steve B on Aug 30, 2020 22:49:30 GMT -5
chinese 50cc air cooled 2 stroke my scooter isnt revving above 7k rpm even on a kickstand 3g roller weights (belt isnt moving all the way up, has 3-4mm travel left) gps speed reads at EXACTLY 60kmph/ 37mph , stock cvt setup , things ive tried: - various exhausts, giannelli reverse, yasuni r, s6 pro replica, yasuni r and yasuni z - 17.5 mm delorto carb and 21mm carb . reverted back to 12mm stock one as i saw no performance change and the 7k rpm limit is still there -6 different cdi's - revving it on kickstand I can only offer you my knowledge whether or not you choose to use it is up to you.
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Post by badumts123 on Aug 31, 2020 8:07:55 GMT -5
chinese 50cc air cooled 2 stroke my scooter isnt revving above 7k rpm even on a kickstand 3g roller weights (belt isnt moving all the way up, has 3-4mm travel left) gps speed reads at EXACTLY 60kmph/ 37mph , stock cvt setup , things ive tried: - various exhausts, giannelli reverse, yasuni r, s6 pro replica, yasuni r and yasuni z - 17.5 mm delorto carb and 21mm carb . reverted back to 12mm stock one as i saw no performance change and the 7k rpm limit is still there -6 different cdi's - revving it on kickstand I can only offer you my knowledge whether or not you choose to use it is up to you. ?
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Post by ThomasTPFL on Aug 31, 2020 8:18:25 GMT -5
One change at a time so if it gets worse you can easily reverse it!
Stock cylinder, stock intake and reed block. If the engine can’t breathe bigger carb and pipe will only make things worse.
If the cylinder is designed to give up at 7k then you can’t do much to change that without swapping or modifying the cylinder.
I bet the exhaust port on that cylinder is super cramped.
How many miles are on the bike? Worn reeds can act like a limiter.
You tried different cdis, were they for a 2t? 4t cdis have a bad timing curve for 2ts.
A failing ignition coil will also act like a rev limiter.
If the belt isn’t moving all the way up you could try slightly heavier rollers, or lighter contra spring.
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Post by Steve B on Aug 31, 2020 11:03:58 GMT -5
Badumts123, Did you ever take the drive belt of and rev it on the kickstand? if not you should do so so because that will tell you whether its restricted or it is the stock port timing. I can tell you one thing for sure 37mph is restricted. By taking off the drive belt you will bypass the clutch bell sensor system.
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Post by badumts123 on Sept 1, 2020 18:47:14 GMT -5
One change at a time so if it gets worse you can easily reverse it! Stock cylinder, stock intake and reed block. If the engine can’t breathe bigger carb and pipe will only make things worse. If the cylinder is designed to give up at 7k then you can’t do much to change that without swapping or modifying the cylinder. I bet the exhaust port on that cylinder is super cramped. How many miles are on the bike? Worn reeds can act like a limiter. You tried different cdis, were they for a 2t? 4t cdis have a bad timing curve for 2ts. A failing ignition coil will also act like a rev limiter. If the belt isn’t moving all the way up you could try slightly heavier rollers, or lighter contra spring. yeah but regardless i think after changing the pipe and different carburators and cdis it wouldve atleast hit 38mph or 37.1, it does NOT go 0.000000001 more than 37mph. I took it to the guy who rebuilt it and he said the crankshaft sensor is bad at high rpms, i dont think theres any crankshaft sensor is he trying to scam me?
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Post by aeroxbud on Sept 2, 2020 8:43:25 GMT -5
I don't think there is a crank sensor. Never heard of one before. To do that same speed regardless of setup, it must have a speed restriction somewhere. Even if it was a really poor cylinder kit. Making not much power. It would still go faster than 37mph down a hill.
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Post by Steve B on Sept 2, 2020 9:33:24 GMT -5
Badumts123, Did you ever take the drive belt of and rev it on the kickstand? if not you should do so so because that will tell you whether its restricted or it is the stock port timing. I can tell you one thing for sure 37mph is restricted. By taking off the drive belt you will bypass the clutch bell sensor system. no i didnt do that but i took out everything in the tranmission up to the crank, theres no sensor for sure. gonna take it to the mechanic who rebuilt it tomorrow. somewhat anxious that he wont be able to fix it since last time i told him theres a limiter he told me "theres no limiter on this mode" and that it was slow due to stock exhaust, hopefully he knows. There is no need to take everything out in transmission up to crank. I wanted you to take the cvt COVER off only. Then on the COVER INSIDE,I wanted a picture to see if there were any empty threaded bolt holes. If so that would indicate that the speed sensor was removed. I don't feel you looked in the cvt COVER by what you said. At least with a photo we can guide you more toward a solution because we can see ourselves exactly whats happening in your'e COVER. That raised area on you're clutch bell is a magnet for reading the speed of the rear wheel. That means the clutch bell speed sensor is close it needs to be close to that magnet to read the speed. 99% of the time that sensor will be on the cvt COVER. You could take the cvt Cover completely off and take a picture of the INSIDE of it. While the CVT COVER "the metal piece with the kick starter built onto it" is off and away from the bike, try revving it up or even take it for a ride without the COVER on. By having the cover off it should disable the "speed limiter" pick up coil from sending a signal to keep it at 37mph.
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Post by ThomasTPFL on Sept 2, 2020 9:42:10 GMT -5
I don't think there is a crank sensor. Never heard of one before. To do that same speed regardless of setup, it must have a speed restriction somewhere. Even if it was a really poor cylinder kit. Making not much power. It would still go faster than 37mph down a hill. Not really a crank sensor, but there is the ignition pick up. That coil failing is a possibility on his issues, but not common. But like I said, I’ve had a failing high tension coil limit my revs. Bad coil was keeping my MB5 below 8000, and that thing doesn’t even make power until almost 10k.
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Post by badumts123 on Sept 3, 2020 9:12:29 GMT -5
Ok so i dont exactly know what he did but he made it go 50mph flat on the gps. (54 on dash) he said the variator was bad and the angles were all wrong so he repolished it and did some other stuff to it, changed the weights to heavier ones, he did change a sensor too and said that removed the stuttering/engine breaking.
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Post by Steve B on Sept 3, 2020 10:06:51 GMT -5
In the end, as long as you are happy and he did not charge you a crankshaft & cylinder kit for it that's all that matters.
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