Technical Chain Tension Advice

[smurth1984]

Hi.
Im am after a bit of advice as my sons honda cadet kart the chain when you spin the wheels by hand the chain goes tight then slack and so on.
I have fitted new chain,sprocket and axle also swapped the clutch over and still doing it.
Any help or advice how to over come this as im running out of ideas.

 

[Seanl]

Potentially it could be a bent axle or worst case, a bet crank shaft where the clutch attaches. Can you see any movement with it started up and revved up whilst in the air and is there any vibration? Also, how much play is there when it's stationary? Should be about 10-15mm - there's a guide from Power Republic in the tutorial section.

 

[smurth1984]

Potentially it could be a bent axle or worst case, a bet crank shaft where the clutch attaches. Can you see any movement with it started up and revved up whilst in the air and is there any vibration? Also, how much play is there when it's stationary? Should be about 10-15mm - there's a guide from Power Republic in the tutorial section.

Its had a new rear axle.
There is about 10mm play on the chain then goes about 2/5mm play.
Crank shaft looks fine

 

[Team13Karting]

Have you checked that the sprocket carrier is straight? That's another thing that can cause play in the chain. As others have mentioned, it's generally something on the drive area, so you're looking at axle/sprocket carrier/chain/clutch/crank etc....

 

[Jason13]

It isn't uncommon for a chain to have tighter and looser spots. Have you tried with a new chain? If a chain has a stretched link(s) this will cause this too. Start with the chain. I had this issue and worried about axel etc. New chain and significantly improved. ME sure clutch and sprocket aligned straight. If axel is straight and clutch new and not damaged. Then only bits left are sprocket and or carrier. Check chain first! Then alignment. Then change sprocket and carrier. Then clutch. Then axel. Not much more it can be to be honest. Absolute worst case crank shaft. But doubt it. Move to tightest spot then adjust engine brackets to provide small amount of play. Check loosest spot to make sure not excessive. All good.

 

[smurth1984]

It isn't uncommon for a chain to have tighter and looser spots. Have you tried with a new chain? If a chain has a stretched link(s) this will cause this too. Start with the chain. I had this issue and worried about axel etc. New chain and significantly improved. ME sure clutch and sprocket aligned straight. If axel is straight and clutch new and not damaged. Then only bits left are sprocket and or carrier. Check chain first! Then alignment. Then change sprocket and carrier. Then clutch. Then axel. Not much more it can be to be honest. Absolute worst case crank shaft. But doubt it. Move to tightest spot then adjust engine brackets to provide small amount of play. Check loosest spot to make sure not excessive. All good.

Thanks for your valued input.
I have just got a new sprocket carrier so as soon as that comes and fitted i will post my out comes here.
Hopefully it will sort the issue as this is the only thing left to change.

 

[Jason13]

Did you change the chain already?

 

[smurth1984]

Did you change the chain already?

Yes Jason.
Changed the following
Rear axle, clutch,sprocket and chain.
Ordered a new sprocket carrier which is due Wednesday so fingers crossed.
When i turn the wheels by hand the chain goes from normal slack of about 1/2inch to about 1/4icnh its only on a very small section of about 1/2 on the turn.
Been told that it should have a tight spot but i causes the chain to bounce on its way back to the clutch sprocket

 

[Jason13]

Yes, that's not enormous fluctuation but in a new chain should be less so there's something going in. Have u very accurately set sprocket and clutch alignment?

 

[Jason13]

Also, when u fitted axel did u rotate in bearings to make sure it's 'fluid', not rigidly fixed at slight angle? Power republic shows a video u can adapt to cadet. After sprocket carrier just clutch to swap. Then only component can be crank shaft. Double check all alignemtns though. Also make sure engine is sitting centrally in frame enabling clutch and rear sprocket to run parallel.