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Right cylinder just let go!


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Oh well, now I get to look into my engine for the first time. Could have done without this right now! I've only just got the bike back together after the crash.

 

Here's what I've done:

 

After my plug chop the other day, I decided to up my mains from 270 to 300. I had been having problems with sticking slides, so gave them a polish up and a touch of grease. ... All back together and fire her up, first kick as usual. 30 seconds later put the choke off. My low running mixture jets had been at 1 1/4 turns out, but I had noticed that the plugs were fouling up quite bad after long idling so I turned them out to 2 turns. Ok, so now I play with the throttle blipping it up and down a few times. Everything's fine, I check the radiator and it feels warm (not hot). I carry on revving her up and down. Still blowing out the usual smoke from the pipes. ... Now I want to make sure my slides have stopped sticking, so I start blipping it to FULL throttle and letting go. And then on about the fourth full throttle blip I start to here bad noises, sudden drop in power, by which time I'm off the throttle. But she makes a horrible grinding noise inside and comes to a sudden stop.

 

I know it's bad! 'Shee won't turn over on the kickstart. Oh shit, how much damage have I done? So I pull the left side plug, looks fine. But I felt if anything it was the right side. I pull the right side plug and the earth strap is closed up a bit and there's bits of metal around the inside and porcelain. I had torqued the plugs to 14 lb/ft, but this right side plug didn't feel as if it had been torqued. ... I guess the piston's let go and with the earth strap bent, the shock has loosened it up.

 

What damage do you guys reckon I've done? And has it been caused 'cos I didn't have her warmed up enough before going crazy with the throttle? ... I'll take any abuse 'cos I feel like a dick for what I've just done!!!!

plugdamage4b9gx.jpg

Rare.

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sounds like a piston may have let loose,and wedged itslf in the jug.thats whay you cant kick it over.thats the reason why i dont like to rev the hell out of her with no load on the engine.time to pop the jugs off.sorry to hear it,make sure you check the rod to see if it bent at all when it jammed up

scott :shrugani:

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well u don't look lean. so if something hit your plug it had to come from somwhere. lower, upper bearing or a piece of the ring. if it is your ring or a stuck piston, it would have done it no matter what, a loose bore would cause this. we will rev our snowmobiles for 30 minutes at a time on a stand to make adjustments, i doubt that your couple of minutes had anything to do with your misfortune. just destiny <_<

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Looks like a ring, my friend. Better a ring than a piston skirt.

 

Next time, check your plugs BEFORE you try to kick it over again.

 

"Horrible Grinding Noises" from deep inside your engine sometimes means that there is a problem. Trying to start it up again can double your trouble real quick.

 

Get it ported while you have it apart, and you might clear those doubles next time! ;)

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Looks like a ring, my friend. Better a ring than a piston skirt.

 

Next time, check your plugs BEFORE you try to kick it over again.

 

"Horrible Grinding Noises" from deep inside your engine sometimes means that there is a problem. Trying to start it up again can double your trouble real quick.

 

Get it ported while you have it apart, and you might clear those doubles next time! ;)

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I don't know what caused it, but you've read my post wrong. ... I wasn't trying to kick it over after the engine failure, i just used my hand on the kickstart to see if it would turn over and it wouldn't. .... The grinding noises weren't there before, they just happened during the failure. Btw, I am ported - MX race port. (That's in my profile).

 

And as for "Better a ring than a piston skirt", this is what I just tipped out of the exhaust!

pistoninexhaust23oc.jpg

Rare.

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dude, that dont look good at alllllll

 

Hopefully it didnt tear up the cylinder to bad

366094[/snapback]

No, it's not good. ... There's a real mess inside the cylinder. I've taken a few pics and will get some more up in further posts.

Oh shit, u mean all that came out of the exhaust? I think that would make me throw up.

It was all just lying in the front pipe when I removed it from the cylinder. And yeah, I'm not feeling too good about this.

 

Here's the first few of the pics:

 

I've pulled the head and the bad side doesn't look too bad. Should clean up ok. (That's a NEW plug in the bad side. I just put it in there for washing the engine).

cylinderhead6pm.jpg

damageddome0fr.jpg

 

Surprise, surprise, I still have two pistons! :shrugani: ... But both are at the top :shrugani::shrugani::shrugani:

pistonsattop8rh.jpg

pistonattop7ic.jpg

More interesting stuff to follow.

 

Rare

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dude that sucks.time to tear her down.like i said before make sure you check the rod to see if it bent at all when it fetched up.unless your going to throw a stroker in her(hint)<<

in a way its good,now you can put it together(money allowing) with some more durable aftermarket goodies like a billet clutch basket and stuff along that nature and all new seals.that way when shes done you know that its done right and should last a while.ya know what im trying to say? :cheers: thats what i did.

scott

 

edit i think u posted pics of your rods the same time i was posting this.diregard checking,u can see plain as day.now go get yourself a long rod

Edited by superchicken
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dude that sucks.time to tear her down.like i said before make sure you check the rod to see if it bent at all when it fetched up.unless your going to throw a stroker in her(hint)<<

in a way its good,now you can put it together(money allowing) with some more durable aftermarket goodies like a billet clutch basket and stuff along that nature and all new seals.that way when shes done you know that its done right and should last a while.ya know what im trying to say?  :cheers: thats what i did.

scott

 

edit i think u posted pics of your rods the same time i was posting this.diregard checking,u can see plain as day.now go get yourself a long rod

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I hear what you're saying. But I've hardly had any time on this bike and the few times when it's all been together it's felt great. I'm not ready for a longrod crank and I've struggled to control the power 'Shee was putting out for MX. Money is tight and I'm fed up throwing the little that I do have at it. ... I was almost there, and now I'm back to square 1.

 

Here's the last couple of pics looking down the cylinder from above. Notice the bottom ring just lying there in the first pic. I then turned the motor upside down and poured another load of bits out. I can now turn the crank, but it gets tight as the damaged rod goes down below. Oh, and yeah, my cylinder has a few chunks out of it at the edges of a couple of the ports. I guess that means I need another cylinder and the expense of having it re-ported. I don't know for sure, but I'll send it off to my engine porter early next week and see what he says.

 

fromabove3ym.jpg

twistedrod21nz.jpg

Rare. (And almost extinct! :( )

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Damn! :whoa: That's tragic bro! Sorry to hear about your misfortune, hopefully it has come to an end now.

 

Please keep posting pics as you fix her up.

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Damn, thats worse then i've ever seen it.. i thought mine was bad.. (Crank bearings coming up and beating right side) Damn, how'd that come out of your exhaust like that! Those are some big chunks!! Time for some wisecos... those stock pistons will do that to you... :shootself: GOodluck!

 

Eric

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