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06 RMZ broken intake valve and piston

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My RMZ took it hard over the weekend when i heard the worst sound i would never want to hear again come from my motor. I just took it apart and the intake valve snapped in half which then caused the broken part of the valve to shoot into the piston making two holes straight through. I know i need a new piston but the valves and area under the cylinder head are messed up and i just want to replace it. Ive been told the cylinder wont come with the valves. Any suggestions on how i dont need to spend a huge amount of money.

2013-07-09 12.28.47.jpg

2013-07-09 12.30.48.jpg

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Unfortunately there will be no cheap way out of this. I'm currently finishing up a rebuild on an RMZ that dropped the intake valve as well. It smashed up the piston, cylinder, and head badly. Bent the connecting rod which seized up the crank too. You appear to have gotten lucky as there is really no damage to the head or valve seats. Just a couple valves. The one I'm working on needs some major repairs to the head.

You'll get away a bit cheaper. New crank, piston, cylinder (I'd be surprised if nothing is damaged in the bottom end as that valve would have prevented the piston from getting to TDC, and somethings gotta give... probably the connecting rod.). Your valve seats got away alright by the looks of it (They were smashed all up on the engine I've got). Cheapest route would be just to replace the valve that broke, but while you're in there I'd recommend doing them all. Buy valves, springs, guides and seals and you're likely good to go. But you're not getting out of this for less than probably $1300 or so, and thats providing you're doing your own labor.

Edited by nstyn8

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Unfortunately there will be no cheap way out of this. I'm currently finishing up a rebuild on an RMZ that dropped the intake valve as well. It smashed up the piston, cylinder, and head badly. Bent the connecting rod which seized up the crank too. You appear to have gotten lucky as there is really no damage to the head or valve seats. Just a couple valves. The one I'm working on needs some major repairs to the head.

You'll get away a bit cheaper. New crank, piston, cylinder (I'd be surprised if nothing is damaged in the bottom end as that valve would have prevented the piston from getting to TDC, and somethings gotta give... probably the connecting rod.). Your valve seats got away alright by the looks of it (They were smashed all up on the engine I've got). Cheapest route would be just to replace the valve that broke, but while you're in there I'd recommend doing them all. Buy valves, springs, guides and seals and you're likely good to go. But you're not getting out of this for less than probably $1300 or so, and thats providing you're doing your own labor.

I knew it was going to be expensive and it is true that i got lucky. But you can tell the bottom of the cylinder where the valves are are a bit messed up. But the way your saying this is that i pretty much have no option but to buy a new cylinder and piston. Obviously it needs to be replaced since there is two holes right in it but The piston is still able to move up and down but something is jamming the cam chain from moving. I figured either whatever broke must of fell down below and caused the jamming or something worst might have happened. But to put it all together in your opinion just to be sure does it look like everything should be replaced pretty much? Me and my dad will be putting it back together but i just want to be sure that i get the right parts and all that even though its pretty straight forward.

WHat do you think caused this?

Edited by spankloads13

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Unfortunately there will be no cheap way out of this. I'm currently finishing up a rebuild on an RMZ that dropped the intake valve as well. It smashed up the piston, cylinder, and head badly. Bent the connecting rod which seized up the crank too. You appear to have gotten lucky as there is really no damage to the head or valve seats. Just a couple valves. The one I'm working on needs some major repairs to the head.

You'll get away a bit cheaper. New crank, piston, cylinder (I'd be surprised if nothing is damaged in the bottom end as that valve would have prevented the piston from getting to TDC, and somethings gotta give... probably the connecting rod.). Your valve seats got away alright by the looks of it (They were smashed all up on the engine I've got). Cheapest route would be just to replace the valve that broke, but while you're in there I'd recommend doing them all. Buy valves, springs, guides and seals and you're likely good to go. But you're not getting out of this for less than probably $1300 or so, and thats providing you're doing your own labor.

Also do you know any links for the websites where i can get all this? Ive been on motosport and motorcyclesuperstore but i want to be sure on what I'm getting

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Yeah man... I'd replace the crank too. Might as well go with a 490cc big bore kit while you're at it. Doesn't cost any more and might as well get an upgrade out of a shitty situation.

While the crank still turns, it doesn't mean the connecting rod isn't slightly bent. I'd be surprised if it isn't. And it might not be apparent until you're spinning it at several thousand RPM.

I sourced all my parts through ebay seller "dirtparts" (all the bottom end stuff), and oemcycle.com for all the top end stuff. You'll do a little better than me as I had to pay a couple hundred in shipping and customs fees, where you'll be able to avoid most of that.

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Yeah man... I'd replace the crank too. Might as well go with a 490cc big bore kit while you're at it. Doesn't cost any more and might as well get an upgrade out of a shitty situation.

While the crank still turns, it doesn't mean the connecting rod isn't slightly bent. I'd be surprised if it isn't. And it might not be apparent until you're spinning it at several thousand RPM.

I sourced all my parts through ebay seller "dirtparts" (all the bottom end stuff), and oemcycle.com for all the top end stuff. You'll do a little better than me as I had to pay a couple hundred in shipping and customs fees, where you'll be able to avoid most of that.

Thats true i mean might as well get everything replaced so the chances of this happening again are low. Ill have to check out ebay.

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may I ask how much time you had on the valves? And how many times you had shimmed them?

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may I ask how much time you had on the valves? And how many times you had shimmed them?

I was the second owner on the bike and i got it a year and a half ago and pretty much rode all summer and fall and just put new shims in before this season. I got one good weekend of riding then boom..I have no idea how many real hours on the bike but a lot is what im guessing

Edited by spankloads13

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I don't know the history of the RMZ I'm working on other that the owner got immediate after a valve adjustment. He put 20mins on it, and dropped the valve.

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I don't know the history of the RMZ I'm working on other that the owner got immediate after a valve adjustment. He put 20mins on it, and dropped the valve.

After reading about it, supposably these bikes were known for this happening but i mean this could happen to any bike in my opinion. I only trail ride and the morning me and my buddies went out it was a good 89 degrees and by the looks of the valves and how they felt when i took them off is that they were sticky. Tons of gunk was on them which probably caused one to stick open? Either way people have told me that i should run higher test gas and mix a little bit of oil if its hot and that will not make the valves get all junked up. Maybe the heat and the straight gas caused this? to be fully honest i have no clue

Edited by spankloads13

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A valve wouldn't stick open, but it could be open at the wrong time.

What does your cam chain tensioner look like now? And was it the original?

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A valve wouldn't stick open, but it could be open at the wrong time.

What does your cam chain tensioner look like now? And was it the original?

The valves were really sticky and all gunked up so it had to off stuck open or just cracked and broke and tensioner is original and is fine

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So sticky that the valve springs couldn't pull them closed? I guess anything is possible though.

I'd definitely add a mechanical tensioner to your shopping list. Would be awful to get it all together and have it do the same thing on you right away.

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So sticky that the valve springs couldn't pull them closed? I guess anything is possible though.

I'd definitely add a mechanical tensioner to your shopping list. Would be awful to get it all together and have it do the same thing on you right away.

Yeah I know its probably hard to believe the valve stuck open until i saw all the crap built up around it...Ive been told if im riding in hot weather to mix a little oil with my gas?

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