way to much vibration

[towdawg818]

Hay guys haven't been on in a while. I changed the gearing on my mini bike. I went with a bigger chain. I went from a clutch with 12 teeth and back sprocket of 60 to a clutch with 11 teeth and the rear has 47. I thought it would be real sluggish out of the hole but it's not. the top end is nice my friends i ride with can't keep up. the one problem i have is my mid range. it shakes allot. Is this the price I have to pay to go fast. If so I'll just leave it alone and drive it like i stole it. If there is something to be done I want to do it. Here is a picture of the bike it's coming along but I'm not done.

 

[125ccCrazy]

make sure the sprockets are running true, have the wheels balanced...

clones have vibration themselves due to poor balancing...may be more noticeable now with a higher top end..

 

[olajoe808]

Quik fix

take the flywheel off, lapp it and when you reinstall it make sure the key is parallel with the crankshaft, not the tip. The key should be level. If you don't have lapping compound use ajax/comet mixed with some dishwashing soap. If your flywheel was not originally seated, this can help to smooth it out.

Olajoe808

Hay guys haven't been on in a while. I changed the gearing on my mini bike. I went with a bigger chain. I went from a clutch with 12 teeth and back sprocket of 60 to a clutch with 11 teeth and the rear has 47. I thought it would be real sluggish out of the hole but it's not. the top end is nice my friends i ride with can't keep up. the one problem i have is my mid range. it shakes allot. Is this the price I have to pay to go fast. If so I'll just leave it alone and drive it like i stole it. If there is something to be done I want to do it. Here is a picture of the bike it's coming along but I'm not done.

 

[towdawg818]

My sprocket's are running true. I'll give the lapping a try and check back in I did not know it would make a difference when I installed my flywheel.
Thanks.

 

[The Restore Kid]

Sounds like to me you gussed it the first time... The violent shake is the clutch coming tight yet can't get TIGHT tight for a while because it takes a minute for the bike to get to speed.. My Suicycle does that too but the engine is rubber mounted and just the way the bike is built ya don't feel it so I don't worry about it.. I do get into the gas slowly though until it's up to speed a little bit.... Sometimes.. like maybe the chain is running loose or there are four breaks in the frame like now.. :glare: But yeah it sounds to me like the clutch hammering the drum trying to pull an imoveable object is the main cause..

 

[olajoe808]

My sprocket's are running true. I'll give the lapping a try and check back in I did not know it would make a difference when I installed my flywheel.
Thanks.

Yea i was in your shoes not long ago and I've asked the same questions. Thank you for the appreciation, mahalo :thumbsup: If you would like to hear what a balanced motor sounds like check out some of my vids. At over 8000 rpms it has a cat's meow.

Rock on from the rockies