Chain tight then loose tight then loose - pitpro125

[synrgy]

I was adjusting my chain and i was just testing it by spinning my back wheel and i have noticed that no matter how i adjust my chain there is always a tight spot.

I will spin my wheel and the chain will be reaally tight, then i spin it a bit more and the chain is at good tension, then spin it more and its way too tight again.

Anyone have any suggestions ?

 

[motoluver]

Worn chain.

 

[Maylands Performance]

Could be a few different things causing this.
Check yer sprockets and make sure there not bent or warped
Your chain being Chinese may be worn out or just plain shoddy from the factory [It happens]
If your chain is a little old replace it B4 it breaks and really causes some damge to your case etc.
Make sure your rear sprocket and bolts are tight [They could be loose]

Cheers

 

[synrgy]

Thanks guys, i will check the sprockets.

Is this a decent chain and do you know if it will fit my pitpro125cc ??

http://www.elstars.com.au/view.php?product=420ms-126l

 

[cass38a]

Is your wheel straight (ie even adjustment on both sides).

 

[THUMPY125]

use vernier callipers to get a even adjustment.

 

[synrgy]

yeh its straight i measured it.

Then i tested either side with a mm difference so one side would be 22mm out and the other 23mm out, still happening.

 

[Meko]

could it be that the front or rear sprocket are machined of centre to the axel??? (so kinda like a cam?)

 

[Poppy]

I was told this is standard with the long travel suspension on bikes these days. Didn't make sense to me but it was the same effect on all four bikes I looked at two weeks ago when he told me. The guy who told me has had a lot of bikes and a lot of recent experience.

 

[Maylands Performance]

It doesnt matter if the bike is long travel short travel or no suspension at all.The chain tension should not vary greatly as the rear wheel is rotated whilst off the groung on a stand [or milk crate ].Of course Chinese machining and assembly tolerances being what they are [cough cough]Tight loose/tight/loose chains are common.Quite often the chinese poor quality chains are the main culprit.Changing to a quality DID,RK, etc brand chain should fix a good deal of this problem.If a top quality chain is fitted and the problem is still evident it is then caused by sprocket teeth mismaching or location holes out of true.As well as all that the sprocket location position on the rear hub can be a contributing factor also !!

Cheers.

 

[sik-pj]

my bikes when i sit down on them the chain goes tighter then when its stand on the stand y is that?

 

[synrgy]

Because when you sit on your bike you apply weight to the shock and you level out the swingarm. When the swingarm is level the rear axle is at the furthest point away from the pivot. Which would mean the chain is at its tightest.

 

[pegleg]

have you changed either your front or rear sprockets lately, if u have maybe its diff from the chain and other sprocket ie: 428 rear sprocket, 428 chain and a 420 front sprocket, believe me it happens, some bike shops dont even ask what pitch u need...

 

[synrgy]

Im gonna buy a new chain from elstar but i need to know what pitch mine is.

They sell 420 and 428. Does anyone know what the pitpro125cc chains are ? I only bought the bike in Feb.

The guy from Elstar has advise pitpro have changed chains so he is not sure if they are 420 or 428. Can anyone advise what size the pitpro would be ?

 

[Flarry]

They are 428 but check to be sure, on every second link on the chain it says the pitch; either 420 or 428.

 

[synrgy]

Thanks flarry ill check it out.

 

[Mack]

This can only be two things. Either the rear sprocket is not mounted centrally on the rear hub or the mainshaft is bent.

I have found that many guys are bending their mainshafts because they are setting the tension with the bike off the ground and they are also setting it way to tight. When you then compress the suspension in use.... well somethings gotta give. Now the biggest problem with running a slack chain is that some of the nastier quality bikes have very poor alignment and risk throwing a loose chain.
Start your bike with the chain off and see if your front sprocket is running out of true.

 

[Maylands Performance]

Hey Mack.Good thinking there,I hadnt even thought of that that one !!!!!!If thats the case not a good scenario there.........

 

[synrgy]

This can only be two things. Either the rear sprocket is not mounted centrally on the rear hub or the mainshaft is bent.

I have found that many guys are bending their mainshafts because they are setting the tension with the bike off the ground and they are also setting it way to tight. When you then compress the suspension in use.... well somethings gotta give. Now the biggest problem with running a slack chain is that some of the nastier quality bikes have very poor alignment and risk throwing a loose chain.
Start your bike with the chain off and see if your front sprocket is running out of true.

Ill check this out tonight

 

[synrgy]

Is the front sprocket meant to be loose ?

When i say loose i mean the bolts are tight but it has play along the shaft.

You can move it 3mm each way along the shaft. Is this right or is it meant to be held firm ?