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Post by dusty350 on Mar 2, 2021 21:04:59 GMT 1
I suggested doing the crank seals whilst it's out of the bike. Anyone that thinks that constitutes a well built engine, and costing 1500, is likely to have scrimped on crank seals I bet. Why chance it ?
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Post by steve63 on Mar 2, 2021 21:05:57 GMT 1
Bores are 1.00 over. The bad piston has no markings apart from the marking you can see. Reed gasket was missing on the side that didn't seize. Dusty Always used to be, all things being equal, that right side went first. It seems like the choke circuit maybe just makes the left.run a tad richer just enough to make it safer? Could that piston be the one that was changed and whatever caused it to need changing has not gone away and just caused this to happen again? What size mains? Air filter?
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Post by freddie19 on Mar 2, 2021 21:07:40 GMT 1
That's just SHOCKING....no other word for it!
Guy shouldn't be allowed to work on engine's if that's what he calls a rebuild!!!😡
One of those pistons isn't even a PV piston!
Just SHOCKING!
So glad I do all my own work when there's cowboys like that out there!🤠
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Post by veg on Mar 2, 2021 21:07:52 GMT 1
Did Dave say he knew the builder and had history for this or am I getting confused? If he is a member on here he should be ashamed of himself. Not that’ll stop him probably doing it again.
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Post by midlifecrisisrd on Mar 2, 2021 21:16:35 GMT 1
Is that standard bore then? Can't see an over size marking on the crown
I recognise that symbol on the non ypvs piston but can't remember what it is
The crumbling front edge of the piston crown worries me. That didn't happen opening it up once
Check the crank isn't twisted
Plugs say rich
The reason I mention standard bore is that if so it's unlikely to be too tight a bore, more likely sloppy but the seizure looks tight from heat. Maybe just sh1t piston
I'd have expected more marks on the inlet side of the piston from lube failure
Steve
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Post by midlifecrisisrd on Mar 2, 2021 21:17:38 GMT 1
Bores are 1.00 over. The bad piston has no markings apart from the marking you can see. Reed gasket was missing on the side that didn't seize. Dusty Is the dodgy piston not marked 100 on the crown? Steve
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Post by steve63 on Mar 2, 2021 21:20:31 GMT 1
Price it all up ere... www.pjme.co.uk/I've used rtv when using used head gaskets.. but not like that.... I feel your gloom giggsy And I've re used reed block gaskets... far better than one of yours.... Thats f'ing basic mechanicing and missing one is.... Thanks, just had a look. What if the big end pins are shot? Last time I had my YPVS crank done it was showing signs of being near the end of its useful life (like me before anyone elses says it 😁). There are a lot of cranks about to just buy and sling in. Some are bad, some are OK. What's people's thoughts on them. Presumably I can't give PJME a crank that was knackered 20 years ago and has been in the garage since and they exchange it for a shiny new one? Incidentally my Mrs said to me the other night that she found a bit of a motorbike in the cupboard in the utility room and did I know it was there? Of course I did, it's an LC crank wrapped in a towel keeping snug, warm and dry silly!
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Post by dusty350 on Mar 2, 2021 21:21:34 GMT 1
Hi mate I mean manufacturers name. Just that logo on the inside of the piston. Dusty
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Post by dusty350 on Mar 2, 2021 21:23:15 GMT 1
And I agree, the logo looks familiar
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Post by midlifecrisisrd on Mar 2, 2021 21:24:23 GMT 1
Pistons look A/C 350/400
Steve
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Post by dusty350 on Mar 2, 2021 21:28:13 GMT 1
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Post by dusty350 on Mar 2, 2021 21:28:53 GMT 1
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Post by abar121 on Mar 2, 2021 21:43:44 GMT 1
Oh my word. That is unbelievable.
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Post by headcoats on Mar 2, 2021 21:49:05 GMT 1
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Post by midlifecrisisrd on Mar 2, 2021 21:51:36 GMT 1
That was one of my thoughts Was the crumbling from coolant hitting the hot piston Steve
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Post by jessy03 on Mar 2, 2021 21:58:21 GMT 1
Well it’s not a £1500 rebuild for sure, looks like you were sold a lemon, if it was mine I would completely start again, strip it rebuild it.
TL engineering will do the rebore, vapour blasting, they don’t do cranks, they just send them to Grampians.
I’d perhaps ask the seller to contribute some funds as it’s clearly not as advertised.
Or you could just throw the engine through his living room window!
Jess
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Post by midlifecrisisrd on Mar 2, 2021 22:01:14 GMT 1
Totally agree with starting from scratch
Can't trust anything in that motor
Out of interest which make pipes are on it and what bore are the silencers
Steve
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Post by chippy348 on Mar 2, 2021 22:03:33 GMT 1
LH piston is a 4L0 OR a Air-cooled piston the logo on that "the A in a star" is a made in Taiwan piston could be a Mitaka Taiwan one OR a KHC brand, either way not a Japanese piston. The RH piston is a YPVS piston. As for the cause, the cylinder / EGT temp i think is what caused the seize, excessive heat on the piston crown then the heat moves down and you loose the oil film. It is not lubrication issue OR from what i can see a piston to bore clearance issue. What i will add is i dont think the main damage was done by the OP, rather than i would have thought it would have been eroding away at the piston for sometime and not in the short time the new owner has had it.
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Post by gazzatt2 on Mar 2, 2021 22:04:47 GMT 1
the red goo looks like hermatite known in the trade as bodgers paste
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Post by 29davyt on Mar 2, 2021 22:05:07 GMT 1
Think id be going through the rest of the bike with a fine tooth comb, if someone’s capable of doing that to a motor who knows what other bodges lie lurking
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Post by chippy348 on Mar 2, 2021 22:06:18 GMT 1
Totally agree with starting from scratch Can't trust anything in that motor Out of interest which make pipes are on it and what bore are the silencers Steve I forgot to ask that ! you must be thinking the same as me
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Post by shaunthe2nd on Mar 2, 2021 22:17:13 GMT 1
It must have been thirsty!
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Post by shaunthe2nd on Mar 2, 2021 22:21:15 GMT 1
I'd be tempted to weigh the pistons to see how out of balance they are. That would have stressed the crank I would have thought.
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ajh
Thrash Merchant
Posts: 415
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Post by ajh on Mar 2, 2021 22:37:15 GMT 1
Think id be going through the rest of the bike with a fine tooth comb, if someone’s capable of doing that to a motor who knows what other bodges lie lurking Exactly my thoughts. This is a big sign the guy doesnt know what hes doing and doesnt care. Might even be a blessing in disguise - If he's attacked the bottom end and gearbox, you might save yourself a big headache in future by going through it now. Do your carbs as well, if hes happy with unmatched pistons and missing gaskets you might have an assortment of jets & needles inside
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Post by midlifecrisisrd on Mar 2, 2021 22:46:22 GMT 1
I'd be tempted to weigh the pistons to see how out of balance they are. That would have stressed the crank I would have thought. No technical stuff like weighing them required Just throw them up the garden, one that goes the furthest was lighter Did A/C pistons run different clearances Makes you wonder if the head leaking caused the first and they just threw an odd 65mm piston in not thinking it might not be the same size or have the same expansion characteristics Steve
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Post by arrow on Mar 2, 2021 22:48:23 GMT 1
I'd be tempted to weigh the pistons to see how out of balance they are. That would have stressed the crank I would have thought. No technical stuff like weighing them required Just throw them up the garden, one that goes the furthest was lighter Did A/C pistons run different clearances Makes you wonder if the head leaking caused the first and they just threw an odd 65mm piston in not thinking it might not be the same size or have the same expansion characteristics Steve Air-cooled clearance is only 1.4~1.6 thou.
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Post by tacky1 on Mar 2, 2021 22:58:31 GMT 1
Now that is a mess, WTF was he thinking of with the red shite, What a mess!!!!!!!
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Post by veg on Mar 2, 2021 23:02:53 GMT 1
I'd be tempted to weigh the pistons to see how out of balance they are. That would have stressed the crank I would have thought. No technical stuff like weighing them required Just throw them up the garden, one that goes the furthest was lighter Did A/C pistons run different clearances Makes you wonder if the head leaking caused the first and they just threw an odd 65mm piston in not thinking it might not be the same size or have the same expansion characteristics Steve Or not giving two f##ks and just selling it on. No point in weighing them or throwing them, near enough a quarter of a pistons missing 😱 Even the finish on the coolant pipes doesn’t look right, guessing they are not genuine or even a decent set. Rusty head bolts etc etc I’d be getting that apart, I’d also be doing the chassis I’ve seen chimpanzees with more care on an Attenborough programme
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Post by giggsey999 on Mar 3, 2021 0:15:27 GMT 1
Thanks for input again everyone, just to clear up one point, the guy I bought it from did not build the engine, he said it had been re built with new crank at a cost of £1500,he never said who did it, maybe he doesn't know, maybe he realised it was a shite job and decided to move it on, only he knows that. So now it's my problem and I'm still not sure what to do with it. I know the right thing to do is compleat strip, I can do the work myself but have very limited space in my garage and the cost is also a factor. I did take a video of the big end movement on the crank so will ask Dusty to post that to get more thoughts on it, the crank spins with no notchyness or rumbles, so even if I end up stripping it the crank may be OK, I will also ask Dusty to put up a pic of the oil pump which does look very clean, poss had re ferb.
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Post by arrow on Mar 3, 2021 0:26:19 GMT 1
Thanks for input again everyone, just to clear up one point, the guy I bought it from did not build the engine, he said it had been re built with new crank at a cost of £1500,he never said who did it, maybe he doesn't know, maybe he realised it was a shite job and decided to move it on, only he knows that. So now it's my problem and I'm still not sure what to do with it. I know the right thing to do is compleat strip, I can do the work myself but have very limited space in my garage and the cost is also a factor. I did take a video of the big end movement on the crank so will ask Dusty to post that to get more thoughts on it, the crank spins with no notchyness or rumbles, so even if I end up stripping it the crank may be OK, I will also ask Dusty to put up a pic of the oil pump which does look very clean, poss had re ferb. I will know if the oil pump has been done by me. No worries.
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