oh dear seized up

[olkno9]

ive had probs with engine , bolt sheered in exhaust , needed to remove head to have rebored, put head back on , didnt alter timing at all just reset as before, when bike was running seemed slightly out so checked timing, seemed a tooth out on front cams so altered and tried again. started fine but got a knock so stopped bike and then tried to turn over using crank and was solid, took both head casing cams and everything down to pistons , crank still solid, oh dear. but valves and everything still fine just crank has seized , anyone any ideas why. engines coming out and getting stripped and rebuilt, will add anything i find when i get to crank but if timing was out y didnt it knacker valves etc .?

[sirch345]

If the piston has seized in the cylinder then I would say you were right in saying that cylinder was running to hot. What we were trying to explain was that if all the valves were not closing fully (were only talking small amounts here) that would cause the cylinder to get extremely hot may be even enough to make it seize.

Did you check the valve clearances when you were trying to find out what your problem was

If on the other hand it's the crank that has seized then that will be more than likely due to an oil shortage, i.e. oil leaked out somewhere or got burnt when using the bike, or oil pump failure

Keep us posted,

Chris.

[tony.mon]

I have a spare crank assembly if you need one.

Came with a box of bits, I only wanted the rh crankcase cover.....

[olkno9]

thnx for advice, ill be stripping it at w/e sowill keep updated, dont think it will have bee the oil as it was new in and not been run in bike so omly option that way is if as u say pump wasnt working. ill update when i get to the crank lol cheers

[olkno9]

with reference to checking valve clearence i didnt think it necceseray as i hadnt touched the valves at all on the strip down so thought all valves would have been operating correctly, may have been a bad oversite of mine.

[tony.mon]

That seems reasonable, as long as the cams went back in the same places.
No need to do more than check clearances, unless the valve seats have been disturbed.
As long as they're within tolerance you can simply re-install.

[olkno9]

yes thats wot my thoughts were, something else i was thinking is if the cam chain has jammed at bottom end off the crank, but ill find that out when i strip her down. typical i make cranks for a living too lol

[sirch345]

yes thats wot my thoughts were, something else i was thinking is if the cam chain has jammed at bottom end off the crank, but ill find that out when i strip her down. typical i make cranks for a living too lol

Good luck with it,

Chris.