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Post by stanlc7189 on Jul 28, 2011 21:55:14 GMT 1
Hi Folks
Further to my previous post "RD350LC Obituary," I have got the engine out and stripped down the top end i.e head and barrels off, and also removed the clutch etc.
I found a strange looking copper thrust washer inside the reed block of one cylinder - totally mangled and bent over double. It looks like it could be similar to the thrust washer that lives next to the big ends - but how could it have got detached? The conrods are both still attached to the crankshaft. Unless the previous owner dropped one into the crankcase during re-build?
Anyway, the barrels need a re-bore and I suspect crankshaft damage of some sort as the engine will only turn over through about 30 degrees before locking up. The layshft spins round quite nicely but I'm probably only guessing and won't know for certain until I split the crankcases, just as soon as I've removed the rotor.
On that subject, can anyone recommend the best method of doing this? I don't have the Yamaha tool but the manual suggests using a 3-legged puller. A set of 3 can be obtained from Machine Mart for about £24. Any thoughts?
Also, can anyone recommend a local (East Midlands area) company that can carry out the re-bore work?
Cheers guys
Stan
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Post by LC_BOTT on Jul 29, 2011 0:12:21 GMT 1
How big is this washer, thrust washers aren't copper, but it could be a conrod thrust washer, thats worn through and come adrift? possibly after the big ends have lost the plot, and exploded.
I would suggest a puller off Norbo, only cost about a tenner, and does the job better than pullers on the flywheel.
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Post by Trubrit on Jul 29, 2011 6:09:57 GMT 1
Hi Stan....Your Welcome To Borrow The Puller I Have Same As The One Norbo Sells .......
Racing Lines In Derby Can Sort Your Re Bore & Crank , Saves Sending Them Off.......
Dave....
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Post by stanlc7189 on Jul 29, 2011 8:45:36 GMT 1
Hi
The washer I found looks very much like the ones that go either side of the con rod at the big end. Thing is..... If it is one of them, how the hell did it detach itself. It is still in one piece although bent over in half and chewed up. The con rods are still attached to the cranks.
Thanks for the advice regarding Racing Lines, Dave. Will give them a call. I've managed to source a pulled too in the meantime but thanks for the offer to borrow yours.
Stan
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Post by lcowner on Jul 29, 2011 8:55:47 GMT 1
big end probably broke apart but sorta jammed in there u wont know exactlytill u split the cases,gl
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Post by stanlc7189 on Jul 30, 2011 11:14:31 GMT 1
Racing Lines have had a quick look at the bottom end (crankcases not split yet) and their Rob thinks the crankpin on the l/h side has failed. Looks like I'm looking at a re-built crank and a re-bore - best part of £500-£600 quid by the time I've finished. Ouch!!!! Still, don't we just love these bikes?  !!!! |
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Post by lcowner on Jul 31, 2011 12:00:14 GMT 1
would u not have a go at it urself ?norbo does new recon cranks fr £220 and £50 for a rebore.really simple to work on and plenty of help about if ur stuck...........
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Post by stanlc7189 on Aug 1, 2011 20:14:01 GMT 1
I am doing it myself. The crank re-build could be up to £320 at Racing Lines, the re-bore is £30 per barrel and then there are new pistons, gaskets etc. Good to know there is help about if I get stuck - much appreciated!
One point, my bike had 31K + 0.5mm pistons in it when I took them out. It's obviously had a re-bore at some point but for what reason? Could that reason have over-stressed the cranks leading to it's failure - unfortunately with me riding it! I think I'll ask to make sure whoever does the crank to fit new conrods as well.
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Post by stanlc7189 on Aug 2, 2011 23:40:04 GMT 1
Just completed the final stripdown. Gearbox perfectly OK, phew! The l/h crankpin totally sheared leaving the crank in two pieces! Thrust washer on big end detached and ingested via transfer ports into barrel slightly damaging the piston and bore. So, it's a crank re-build including new conrods, re-bore and new pistons i.e a new engine!!
Don't yer just love these old bikes???!!!
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lcolin
Thrash Merchant
Posts: 497
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Post by lcolin on Aug 4, 2011 20:19:04 GMT 1
if its got tits or wheels, it'll give you trouble!
but you wouldn't be without either!!
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Post by bryan on Aug 4, 2011 23:56:01 GMT 1
im lucky and get cranks done localy at £179 with new rod kit and main bearings and both barrels rebored with Mitaka pistons for £140 and dont need to pay for postage both ways, so shop around and dont just accept the first price you are given.
Norbs can sort you a crank and pistons and possibly get your barrels rebored, wouldnt cost much more to send them with the crank as its exchange.
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Post by stanlc7189 on Aug 17, 2011 1:28:46 GMT 1
Just like to announce the return to service of the LC. Finally got it re-built and fired it up today for the first time. Went third kick! Lot's of smoke to start with and a slight coolant leak from the head gasket. Just re-torqued the head and some bolts needed quite a tweak.
First sortie tomorrow pm - nice and easy. Any tips for running in what's virtually an all-new engine?
PS. I can thoroughly recommend 'Racing Lines' in Derby. Crank and barrels delivered to them on Tuesday, ready on Friday! Thanks Trubrit for recommending them - not cheap but excellent service!
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