I haven't measured it, but...

The chain set on my (new to me) 2009 evo250 looks to be in reasonable condition; but the chain is slack, almost touching the swing arm.  However the snail adjusters are at their max rotation. I suspect a smaller sprocket than standard is on it.

So, how much length will I get if I turn the adjusters to thier minimum setting?  Enough to cut a link off the chain so I can set it up at the correct tension?

 

You can test this yourself by moving the axle forwards then undoing the spilt link and overlapping the chain ends on the rear sprocket.

If one link difference is too much, the normal fix is to fit a "half-link". These are readily available

As said by feetupfun, but be aware no two 520 chains are the same, so the half link needs to be of the same make. Regina chains are good quality, and half links are generally available from Inmotion.

Thanks all.  

Looked at it this morning and I could take out a link, but then it appears fairly tight (pulled taught is about  two fingers width to the bottom of the swing arm.  But I now have another question:

The front sprocket is loose.  I have owned a lot of bikes, but never a Trials bike, and never a Beta, and have never seen this before.  There is movement forward/back and up/down as well as rotationally.  I am figuring this is the wrong sprocket, but happens to fit loosely on the splines.  Can you confirm - or are all Beta like that?  Pretty sure it must be wrong and tightening the chain with that may put extra load on it, so will leave it loose for now.  For ref, the sprockets are 11/43 and I count 50 links in the chain.

 

update - edited an hour later - the front sprocket looks right, spines are OK, but it just mounts on the shaft between two circlips so has the movement I felt.  Should there be spacers or washers in there to hold it firmly, or are they loose?

Edited April 25, 20233 yr by McTrucky