Need a pro's help!

[adrian101]

I placed a 36 t sprocket on my motorized bike today.

1. When i kick the motor over an begin to ride every now and then i hear a "clunk" noise coming from the back wheel and chain tensioner area. its like a "thump OR snap noise". I'm to scared to ride my bike due to the problem

do you know what the problem could be?
How tight should the chain be?

When i had the 44 t sprocket on it i didn't have the problem.

2. when riding, if i go over half throttle my engine makes a bogging down noise and decreases in power . I have checked for air leaks in carby, inlets, muffler the whole lot and no air leaks. I played with the air/fuel screw and still no change.

Do you know what the problem could be?

please help me

 

[adrian101]

Update, I fixed the bogging down problem... i took the carby apart completely, cleaned everything twice to make sure it was clean, gasket glued the seals shut, locktite all screws then put it all back together.

I placed Clip on the 3rd notch on the needle and moved the idle screw out 3 2/4 turns and it works perfect.


The clunking noise is still there thou

 

[DuctTapedGoat]

That's your chain almost skipping off the sprocket. Make sure your sprocket is 100% perfectly centered, and try to leave about a cm slack in the chain.

 

[oldguy387]

I had the same problem and kicked a chain. What the noise is could be the chain hitting the spokes. Move the tensioner out away from the spokes and line up the sprocket better. That is what I did to fix my problem. I also took just about all slack out of the chain to make sure the sprocket and chain would link up properly. Hope that helps.

 

[Motocruiser]

@adrian101: Make sure your idler pulley is lining the chain up correctly. As fas as how much tension, your drive chain should be as tight as your crank(peddle) chain. hope this helps.

 

[DuctTapedGoat]

Another thing - what size chain do you have, and if it's 410 or larger does your sprocket accept 410+ chain?

 

[adrian101]

@ducttapegoat I have a 415 heavy duty chain. i took my sprocket off and i can't get it on 100% perfectly centered. The sprocket isn't bent nor do i have a buckle in the wheel. It just won't go on perfect. i spin the wheel and the sprocket is un-even.. I have even busted open my fist like 5 times tying to get it on correctly.

What is the best configuration to put it on.. I have been doing one nut and bolt on 1 side, then doing another on the opposite side. like a star or X patten.

The guy i purchased the sprocket off said it suits all chain sizes.

also with the cm slack, do you mean if i push the center top of the chain to the bottom of the chain it should be a 1cm slack/gap?

 

[Skyliner70cc]

Some sprockets need to be filed/sanded to knock some of the chrome on the teeth. I used to run new sprockets on my belt sander to do so which fixed the problem of chain binding/jumping.

 

[DuctTapedGoat]

A full centimeter of movement if you pull the chain up and release it - it doesn't count now if it's tight and you're just stretching it, talking actual slack.

A tip to center it well.

Take an old pair of forks and concrete them upside down. Now, you can spin the wheel freely and visually see how centered the sprocket is.

 

[adrian101]

Just an update: @ducttapedgoat, I placed the 44t sprocket back on my bike, It is 1.5mm off center but rolls with the chain nice as the back wheel has a small buckle in that area lol

Thank you for your tips and help.