ok my 12 yr old son has a new sky hawk motor on a new bike cant keep the chain on it , seems to have proper tension also cant kick start it with peddle like mine he must peddle off and develop speed . engine acts like it has the compression of a 500 cc 1 lunger , that's why its not capable of kick starting with peddle. chain alignment seems good also, has only run it about 10 min. and 100 yrds between chain pop offs. thanks for any help. ready to crush the ---- thing nearly, bike is a 99.00 delmar schwinn 26"
chain falls off
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freewheeling frank
New Member
sounds like maybe the chain is too tight and binding,hope this helps,frank
Bikeguy Joe
Godfather of Motorized Bicycles
Look down the chain to be sure the run is straight. About 3/4" of free play at the middle of the top run.
Also, on some bikes, you have to twist the tensioner slightly so it runs true with the chain.
Also, on some bikes, you have to twist the tensioner slightly so it runs true with the chain.
bairdco
a guy who makes cool bikes
as far as "kick starting" it goes, i haven't had a bike that does that yet. i have three of the same motors, and all of them require a different starting method. one you can just roll it out into the street and it fires right up, one takes 20 feet of pedaling, and one takes a half a block.
they all run great, they're just different.
they all run great, they're just different.
Goat Herder
Gutter Rider
Welcome the the forum Remnant. This might be an interesting read for you. Cheers
http://motorbicycling.com/f11/chain-tensioner-suggestions-11815.html
http://motorbicycling.com/f11/chain-tensioner-suggestions-11815.html
KCvale
Well-Known Member
I never use a tensioner on the motor chain.
The reason everyone does is because the kit comes with one and suggests you use it on the chain that came with the kit as that is what you are already working on.
But think about it.
A tensioner is not some crucial part that needs to be on, it is a fix for a simple chain length mismatch problem.
Fix the actual problem and you don't need a fix for the symptom.
This is the Grubee GT1 bike and GT2B motor bike I am almost done with.
I used a 1/2 link on the drive chain and got to only about 8mm to long.
Then I put a flat shim between the motor and the seat post mounting block to take out the motor chain slack.
For shims I just use what I have plenty of, the slot covers on computer cases. After 27 years of building computers I have a box full.
I just fold it in half and put some thin packaging cardboard pieces in between until I have the thickness I want and put in it. As a bonus the little lip on it keeps it from falling through;-}
But even if you don't want to mess with that, at least consider putting the tensioner on the pedal side.
You don't need to use a big ugly heavy duty bolt on tensioner either.
Your pedal chain hardly gets any use and simple little bicycle tensioner will work fine.
If tensioners were a good thing on a motor driven chain, all motorcycles would have them right?
It is a little more work, but in my book worth every minute of it to avoid an un-needed moving part in the main drive so I do that on everything I build.
The reason everyone does is because the kit comes with one and suggests you use it on the chain that came with the kit as that is what you are already working on.
But think about it.
A tensioner is not some crucial part that needs to be on, it is a fix for a simple chain length mismatch problem.
Fix the actual problem and you don't need a fix for the symptom.
This is the Grubee GT1 bike and GT2B motor bike I am almost done with.
I used a 1/2 link on the drive chain and got to only about 8mm to long.
Then I put a flat shim between the motor and the seat post mounting block to take out the motor chain slack.
For shims I just use what I have plenty of, the slot covers on computer cases. After 27 years of building computers I have a box full.
I just fold it in half and put some thin packaging cardboard pieces in between until I have the thickness I want and put in it. As a bonus the little lip on it keeps it from falling through;-}
But even if you don't want to mess with that, at least consider putting the tensioner on the pedal side.
You don't need to use a big ugly heavy duty bolt on tensioner either.
Your pedal chain hardly gets any use and simple little bicycle tensioner will work fine.
If tensioners were a good thing on a motor driven chain, all motorcycles would have them right?
It is a little more work, but in my book worth every minute of it to avoid an un-needed moving part in the main drive so I do that on everything I build.
BarelyAWake
New Member
I defo respect yer ingenuity & agree with what you've said with only some small additions...
Unfortunately some frames require the use of a chain tensioner to redirect the drive chain because of chainstay clearance issues, there's also some frames that have near vertical dropouts & even with 1/2 links it's not always feasible to try and get a "perfect" length due to "stretch".
But I wholeheartedly agree that if you can manage w/o one - it's far better
Unfortunately some frames require the use of a chain tensioner to redirect the drive chain because of chainstay clearance issues, there's also some frames that have near vertical dropouts & even with 1/2 links it's not always feasible to try and get a "perfect" length due to "stretch".
But I wholeheartedly agree that if you can manage w/o one - it's far better
KCvale
Well-Known Member
Thanks ;-}
It is nice to have a new second business with plenty of room for improvement with a little thought.
And of course experimentation, I think I like that best ;-}
Creative Engineering
New Member
I'm done!!!
I did this over a year ago, (and posted the "how to"), and no one responded.
KC...I wish you the best in your business endeavor!
Jim
I did this over a year ago, (and posted the "how to"), and no one responded.
KC...I wish you the best in your business endeavor!
Jim
GoFastBicycles
New Member
Al.Fisherman
New Member
LOL How much does you 12YO weigh. I'm 210# with a heart condition and I can start a bike in a shorter distance then my 135# 34yo son (even in grass). These things need weight on the rear tire.
bairdco
a guy who makes cool bikes
dontcha hate it when you give the best advice you can, and you know for a fact it's good advice because it works for you, but then people just totally ignore it or do something completely opposite of what you told them?
the way i'm trying to look at it, is some of us can jump on our bikes and go riding whenever we want, and others, well, they can't.
(edit) don't mean anyone specifically, just empathizing with Jim
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Comrade Alfonzo
New Member
I'm just waitin on a new chain, the chain tenioner has tried to kill me and ended up twisting the chain, I'm using the screw through frame method. I'll make the kill switch work later.