Honda-SOHC
SOHC.co.uk Forums => Other Bikes => Topic started by: Laverda Dave on November 12, 2017, 12:03:09 PM
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Hi All,
I am currently in the process of cleaning and measuring all the gearbox parts of the CB250RSA engine. So far it's all pretty good with no undue wear although I'm installing a new cam chain, tensioner, refaced rockers and a NOS cam.
I am having trouble with the balance shaft chain in terms of measuring for wear. There's nothing in Mr Haynes manual regarding what is acceptable wear. I've clean the chain in degreaser and laid it out as in the photo. The chain length is 283mm (doubled up, it's endless) and it has a deflection of 25mm as shown. Is this acceptable, it doesn't have a hard life as it's inside the engine and covered in oil?
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If you wrap the chain round the sprocket you are going to use it on and pinch the loose ends with one hand, then try to lift the chain links from the sprocket at the furthest point from there. If you can lift the links up away from the sprocket teeth it shows them chain has too long a pitch, meaning the pins and bearing's area are worn too much.
Sounds much longer than it takes to do but any slack above just a little movement means the chain needs replacing.
Assumes the sprockets aren't knackered as well, but more likely on final drive chains.
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Thanks K2-K6, I'll give it a go during reassembly. I've got an order to call into DSS tomorrow and shall enquire about the cost of a new one. To be honest there was only half the adjustment taken up on the balancer mechanism before I stripped the engine so hopefully it's all OK.