Is that a popping I hear?

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bronson9

New Member
Jun 18, 2010
18
0
0
Nashville
So i've got a china 80cc 2stroke.
When I pull the clutch in and free roll (walking along side the bike at a slow speed) every so often there is a popping or clicking coming from the inside of the engine sprocket casing. The wheel is true, and the chain is tight. I don't seem to notice the sound when the bike is running or when I am coasting with the engine running and the clutch pulled in.. I hear it mainly only when at walking speed with the clutch pulled in... do I have a problem? Is a problem on the rise? :p thanksss

oh and also...,

Is it ok to only use the drive chain and eliminate the chain that came with the bike ? It is old and streched and rusted and quite the nuisance while trying pedal to gain speed..
 
Mac

Mac

New Member
Dec 3, 2009
486
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Maine
Put your hand on the clutch cover when the motor is running and the clutch is not enguaged, bet it quiet's right up.
 
2door

2door

Moderator
Staff member
Sep 15, 2008
16,302
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63
Littleton, Colorado
If this is a new build its possible the chain is catching on some rough edges of the drive sprocket. There is also an area inside the clutch actuator cover that often interferes with the chain. Remove the cover and inspect it for contact near the front edge where the chain rides over the sprocket. http://motorbicycling.com/f4/chain-noise-6682.html Is your chain well lubricated? Is it the kit supplied #415 chain? They can have some irregularities that will cause noise and binding.
As for your final question; I'm not quite sure what you're asking. Could you be more specific?
Tom
 
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Dougan

New Member
Apr 5, 2010
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wisconsin
I'm sure there could be several causes.

I just had this problem, though. Mainly at low speeds as well. Took the cover off and realized there was sand in the area. Wiped as much down as I could, and then I took out the clutch arm (barely could turn it due to the sand) and cleaned that down with brake cleaner. Took the metal pin and ball out of the middle of the sprocket and reapplied bearing grease. Then gave everything, including clutch arm, a healthy dose of marine gearcase lube (only oil i had around that wasn't 2 stroke or WD-40 :) ). Put everything back together and it oslved the problem.

As for your drive chain question, you'd have to set your motor to idle and then to start it you'd have to kickstart it by lifting up on the bike frame so the rear wheel was off of the ground when you started it. Then you would have to put the clutch in gear slowly, like a car. This doesn't sound very nice but it works. But I like being able to pedal. Makes starting easier, allows a 'limp home' mode and allows me to assist when going uphill. So technically you could, but i doubt you would enjoy it if you did.
 
bairdco

bairdco

a guy who makes cool bikes
Aug 18, 2009
6,537
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63
living the dream in southern california
if it's a steady, rythmic popping, it could be a stiff link in the chain. if you spin the back wheel very slowly, watch as the chain rolls off the rear sprocket. you'll see the chain bend unnaturally, like one link won't straighten out right away. it usually happens where you re-joined the chain after removing links.

if that's what it is, to fix it, spin the wheel till the link is in the middle between both sprockets, then grab the chain with both hands on either side of it and bend it back and forth, the way the chain's not intended to bend. that will work the stiff link back into shape.

could also be normal. these bike's make all kinds of weird, imposing sounds.

as far as removing your pedal chain, then you'll have to scooter your bike around to start it.
 
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bronson9

New Member
Jun 18, 2010
18
0
0
Nashville
thank you for all of your helpful replies....

So I took off the engine sprocket cover and took the chain off, cleaned off the sprocket, casing, clutch arm etc. because their had been some excess dirt and debree brought in by the chain lube i had put on it... ( just canned lithium grease..? ) This quieted the clicking or the the knocking or whatever it is when the bike is free rolling..This IS a new build so it could all be coming from the stock chain that came with it..just wanted to make sure I wasn't headed for something disasterous. I'm sure ill work the kinks out. thanks again so much for the help
 
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