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Post by johnoe47 on Nov 12, 2021 19:22:56 GMT
  When I bought my cb250n the pervious owner stated that it had just had a top end overhaul. However on initial start up although it sounded OK it leaked oil from the head bolts, On inspection it turned out he (or a friend?) had refitted the bolts incorrectly and one didn't have a lower seal. My local breakers supplied me with a replacement bolt and after fitting there was no more leaks. After getting the rest of the bike back to standard (he was in the process of turning it to a cafe racer) I took it out for a ride two weeks ago. All OK apart from a clatter from the crankcase area. I thought balance chain adjustment, but on deeper inspection the chain was actually broken ! On to this week and engine removal and internal inspection showed that when he had fitted the bolts incorrectly one had pushed through into the crankcase and pushed the ally against the balance chain breaking not just the chain but the sprocket too! Hopefully a drop of epoxy will cover the base of the bolt and I have obtained a chain ,shaft tensioner and two balance weights from ebay. A lesson to be learned,Don't trust a previous owners description as Gospel  |
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ian
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Isle of Man
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Post by ian on Nov 12, 2021 21:35:30 GMT
Sounds like an expensive lesson too. I can't say too much about the head bolt error though - when I rebuilt my 400 engine, before this forum or it's predecessor existed, I thought who's put that c**p on there, removed the c**p & cleaned it all up nicely. Needless to say oil spewed out & another strip down followed.....  |
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Post by buster on Nov 13, 2021 8:57:47 GMT
ouch!
I personally wouldnt trust epoxy, most glues can be removed with boiling water ie 100 degrees C, if it was mine I'd get it welded for peace of mind
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ian
Member Of The Year 2019
Isle of Man
Posts: 5,255
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Post by ian on Nov 13, 2021 21:46:27 GMT
I used some kind of epoxy on mine & it lasted a few years, then 400 bolts came available so I got a couple & pulled it apart yet again. When I did the 250 a couple of years ago I just got the slots welded up, issue solved forever. Should have done that on the 400, although I think the rubber seals will outlast me now  |
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Post by reversespin on Nov 15, 2021 10:31:54 GMT
Had the same experience.
Knew an Aluminium Welder/Bike Engineer he recommened using some Automotive Silicon to seal hole.
Still think welding the better option though.
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Post by johnoe47 on Nov 15, 2021 19:17:22 GMT
I've used metal epoxy putty, just a small amount mainly to stop any oil being pressured up the bolt threads.There is no loading on it so should be OK.
Must say aligning up the balance weights was a bit of a palaver.
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