Catastrophic engine failure [SMR 510 seized]

So, I went to local track while it was closed to take some pictures with my friend. As I was coming towards him while spinning the rear tire on the dirt with maybe 1/4-1/2 throttle, the bike just died. Thought I've blown a fuse or something, because it just died. No mechanic clatter or rattle sounds came from the engine. Tried starting it again and all I could hear was clicking from the electric starter, but it wouldn't even spin the gears. We tried to push-start the bike, but the rear wheel would just lock-up every time.

After a while we went get my friend's trailer and loaded the bike up. On the trailer I noticed it was dripping oil from a hairline crack in the left half case next to the stator cover. Seemed like the counter-ballancer or something hit the case.

WARNING,
THE PICTURES YOU'RE ABOUT TO SEE MIGHT BE DISTURBING TO SOME PEOPLE, PROCEED AT YOUR OWN RISK!



Popped the head and cams which seemed fine. The cylinder was a b*tch to get off, but revealed this...


Found some discolored pieces of metal inside.


The conrod is cracked at the bottom and bent. That small square at the bottom is the counter-ballancer. CAN THE CRANKSHAFT BE REUSED IF I TAKE IT TO A PROFESSIONAL TO CHANGE THE CONROD AND TRUE IT?

This is the only dent in the cylinder from a small piece of the piston ring.


Could this cylinder still be reused without replating? It would burn oil, sure, but just for a little while, so I could get the money to fix it.

Don't think this matters much because it's not Nikasil plated.


Found this laying around the starter gears when I opened the clutch cover, and have no idea where it's from. I checked the entire manual and all the OEM parts cataloques. I'm guessing it's from behind the clutch assembly, but how am I going to get a new one if no husky dealer sells it?

Your con rod can easily be rebuilt. That cylinder is plated. You may be able to use it again with out re-plating.

I'm not 100% sure about the terminology of the engine parts (in English), but by "con rod" you mean the crankshaft and not the rod that's cracked and twisted, right?
By the second to last picture I didn't mean the cylinder wasn't plated at all (I know it is). I mean the small scratch in bottom of the cylinder with goes into the bottom end.

The mystery part is the clip that holds the one way bearing together.
Later George

regardless of pieces the cases need to be split and the engine needs an entire rebuild...what I saying is what is what can go on for weeks like so many internet posts. fact is you blew the motor now take it completely apart and rebuild it. or have it done by a competent mechanic.

Yes the connecting rod "con rod" can easily be replaced on the crankshaft by someone with the proper tools.

wow, juice.

just wow.

good luck.

Hi George,

Do you know which bearing is that?

The bearing is 8000a0709 and the clip to hold it in is 8000a0710, you can find them on the kick start page of parts on the parts diagram.

The crank can be okay but the case is cracked.

i would not subject a new piston and rings to that dinged cylinder. A re-plate would cost what $200?

the piston and rod will cost $400.

I'd look for a used motor on ebay or something.

Currently I'm leaning towards re-plating the cylinder even though I have to send it to Germany since nobody does this kind of work in Finland. Already found a pair of used cases from a 450 SMR (They were cheap and in a great condition).
Project is currently on hold till spring comes around. Only thing left is to choose which mainbearings to use. The OEM held up this long (21000km/604H) so I might choose those even though they're 60€ a piece. A local shop of mine sells the same size bearings for a KTM 640 and Honda CR 500. They also sell C0, C3 and C4 bearings and I have no idea which to buy

The "C" numbered bearings denote the clearance in the bearing itself. Some are made looser than others I guess to accommodate expansion under heat.
I'm sure the same size bearing for a KTM or Honda will work fine. It's a dirt bike not the space shuttle.

The OEM Bearings have a groove machined in them for the retainers to hold them in place but maybe you do not need this.

Didn't know that. My guess is that the needle bearing of the conrod went out first so that's what I'm afraid of in the future. Luckily the wossner conrod kit includes that bearing and I'm sure it's better than the OEM. Planning on doing a piston swap at 250h and complete rebuild at 500h from now on.

Just asking, how often you chance your oil, how long have you own that bike, i mean it is used, if so you dont know how often they was chance, when i´am interest that case. Also those mainbearings was ok condition still??

Bought the bike with 15000km/400-500H. To my understanding the engine was never rebuilt. You might be thinking that's stupid to even ride it with this many hours.

Reasons why I did:
This is a big block road-only bike (never raced or ridden off-road so only thing that could explain the hours is sitting in traffic)
Took the engine apart last winter and everything was barely worn. Rod had no play, piston could've been reused but swapped it anyway, 0 scratches in the cylinder just to name a few.
The bearings in my 125 2-stroke lasted easily 20000km so I assumed the bottom-end of a 4-stroke should last longer.

I swap the oil every 20-25H (cityriding, exploring off-road, stuntriding). 1000km if I'm commuting on the highway. I also check valves 3-4 times a year. Only once did they need adjusting. I haven't split the cases yet because I don't have the tools to do so, but from what I've seen so far, the main bearings are OK. It was the connecting rod's needle bearing which failed.

That mileage may seem high to some, but olderhuskyrider on here documented his journeys with his TE450 and had put 20,000+ hard off-road miles on his and sold it to his buddy. The bike was stolen unfortunately, but it was still going strong. Don’t underestimate these Italian big blocks. Probably one of the best engines ever put in a husky.