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RM85 CYLINDER DONE FOR - CAN THIS BE SAVED?

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I have a 2015 rm85 that lost all compression at Durhamtown a few weeks ago. We ordered a new wiseco piston & rings and replaced them - the bike fired up and ran for about 5 minutes before the wrist pin shattered and lodged part of the bearing in the cylinder wall (simultaneously destroying the new piston & ruining the cylinder - see pics).  So, a new cylinder & piston kit was ordered. We put them in last night... The bike fired up, ran like a champ through a warm up / cool down cycle. And then again in the morning for a 2nd warm up / cool down cycle. On the first ride, she lasted a couple of laps and ran beautifully, until it just locked up. No warning signs, no hard shifts, no lag, no warning at all - just stopped. This time the brand new piston and cylinder look worse ( the piston was gouged on both sides and one side of the piston was actually crushed in - no pics of that, I was too upset), although no pieces of anything came out with it when we took it apart - just saw all the gouges in the brand new cylinder and piston 😭. I'm thinking part of the wrist pin is still floating around in the crank and came up with the piston during the first ride. Anyways, my question is whether or not you think this original cylinder can be saved somehow without having to order another brand new one - part of the wrist pin is still lodged in it. We plan to tear apart the bottom end and see if any pieces of the wrist pin bearing are floating loose around there and will hopefully find an undamaged crank & will get any pieces out to keep this from happening again. Would you have it bored? Re-sleeved? I've never had to do this before. Pictures for reference. Thank you all in advanced. 

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That can no doubt be welded up by a specialized re-plating / cylinder shop but you'll have to get quotes

from them as the labor cost risks to be close to the price of a new cylinder.

Avoid installing a sleeve in a initially plated cylinder unless it's an impossible to repair/replate/replace unit.

 

As your bottom end is split open to clean out possible debris,

if unknown hours or over 60, I'd preventively refurb the crankshaft/rod/bearings/crank seals while in there.

Peace of mind that may save yourself the pain of a 3rd consecutive failure.

Edited by mlatour

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16 minutes ago, mlatour said:

That can no doubt be welded up by a specialized re-plating / cylinder shop but you'll have to get quotes

from them as the labor cost risks to be close to the price of a new cylinder.

Avoid installing a sleeve in a initially plated cylinder unless it's an impossible to repair/replate/replace unit.

 

As your bottom end is split open to clean out any debris,

if unknown hours or over 60, I'd preventively refurb the crankshaft/rod/bearings while in there.

Peace of mind that may save yourself the pain of a 3rd consecutive failure.

Awesome thank you. I was worried it might be beyond saving somehow. It was the original and has not been repaired before. Do you recommend any reputable companies for something like this? I'm in Florida but not opposed to shipping it off to the right company. 

That is great advice. After all of the parts we've put in over the last 2 weeks I'll definitely want to take care of the crank to make sure. I'm already quite worried that a piece of the wrist pin may have caused some damage to the crank, because the rods in that wrist pin that lodged in the cylinder are a very strong metal and could definitely do some damage. 

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Others will have to chime in for shop recommendations as I'm located in Canada.

Perhaps ask in your regional sub-forum.

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I’m sorry for your expensive problems. As you should now know anytime you blow a top end (where parts break into pieces) you must fully disassemble the engine and inspect the crank and bearings and at least clean out the bits of metal. Normally I’ll replace the crank bearings and rebuild or replace the crank. It’s easy to bend the rod too so replacing it makes sense.  It does sound like your second failure was likely from debris left from the first failure. 
Your cylinder appears to be about $534 from RMMC. Not sure what you paid when you bought the new one but it pays to shop around; oem prices can vary substantially. Check various high volume sources like Motosport Outlet, RMMC and you can even get deals on eBay too. With that said that cylinder appears repairable by a replating shop. I’ve used Millenium Technologies with excellent results. The last one they did for me looked worse than yours (my piston exploded from detonation)and cost about $200 but that was about five years ago. I can’t estimate what they’d charge you but I’m reasonably sure it’d be far less than a new one. Good luck

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New cylinder works cylinder on motosport for three and a half. I'm sure if you did some searching, you could find a good used replacement for much less.

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