05 250f grenaded!!!

[nic_brestel]

Was out riding today and having a great time. Was there for bout two hours. My friends honda 250f rear brake quit working so i was just messing around waiting for him to get it fixed. Took a small double, landed alittle long and all the sudden kaaa boooommmmm!!!!!

Heard alot of bangs and grinding noises. Took the valve cover off and got it to tdc the intake cam was about 90degrees off and the exhaust about 60-70degrees off. Gonna take it apart tomorow. Let you all know what i find inside.

[Luigic81]

damn, sorry to hear that man. How old are the valves and piston?

[nic_brestel]

Dont have an hour meter on it but id say bout 40-45.

[D-K]

Do you think that the camchain or tensioner failed?

[nic_brestel]

From what ive got took apart so far im thinking it was the tensioner. It was almost all the way in with no tension on the chain. Hoping to get the head off later today i see what else i find. Few metal pieces came out when draing oil. Cant look to good on the inside.

[Luigic81]

No fun, Well I hope it's only the top end thats damaged. (where's the crossed finger's smiley when you need it)

[nic_brestel]

Well its been a great bike. No serious trouble until this happened. Im ready for a new bike. Have really been thinking bout getting a 09 but didnt really have a reason to, but now i think its time for a new machine. Gonna try to part out whats good and use for a down payment.

[D-K]

Well its been a great bike. No serious trouble until this happened. Im ready for a new bike. Have really been thinking bout getting a 09 but didnt really have a reason to, but now i think its time for a new machine. Gonna try to part out whats good and use for a down payment.

?

If the weather holds up somewhat this week I might give my -09 the virgin ride this upcoming weekend. Word is out that a sandtrack around here has dried up enough for the place to open... I´ll give you a report on how these babies run!

[Luigic81]

Well its been a great bike. No serious trouble until this happened. Im ready for a new bike. Have really been thinking bout getting a 09 but didnt really have a reason to, but now i think its time for a new machine. Gonna try to part out whats good and use for a down payment.

Hopefully it's not as bad as it sounded in there and you can fix her up for under $1000 and sell it.

[nic_brestel]

Well they are selling for around 2500 here in good shape. So i dont want to spend spend 1000 if not more just to make a 1500 profit when i can probly just as easy sell whats good for 1000-1500

[Luigic81]

that makes sense

[dvn]

From what ive got took apart so far im thinking it was the tensioner. It was almost all the way in with no tension on the chain.

Sounds like you let the cam chain go too long. When you install the tensioner on a good chain it shouldn't go out more than a few clicks.

[nic_brestel]

Sounds like you let the cam chain go too long. When you install the tensioner on a good chain it shouldn't go out more than a few clicks.

We had it apart to shim it bout a month ago and things were fine. Nice and tight. I think the tensioner just broke. It slides freely back and forth now

[D-K]

We had it apart to shim it bout a month ago and things were fine. Nice and tight. I think the tensioner just broke. It slides freely back and forth now

Yes, the tensioner can break.

But something else failing could potentially pull on the chain hard enough for it to blow out the tensioner.

The hard thing usually is to determine in what sequence things broke. It´s usually not what you think when you first look at it.

Maybe there was an oil problem causing cams to seize.

Or the main bearings let go and the crank wobbled and put so much strain on the chain that the tensioner basically exploded.

Either way, when there is a chain problem it usually gets ugly...

But if you´re lucky nothing too bad happened...

[Jonah52]

that sucks man. An 09 would be cool but if your tight on cash look for a nice 07 or 08 just make sure its been taken care of.

[nic_brestel]

Got the head off. Top end is fine, no marks on the head, valves. Cams spin, buckets look good. Piston looks good. havent took cylinder off yet.

If you look down where the timing chain is there is chunks of metal and something is cracked in the case.

[Luigic81]

you splitting them tonight?

[Rambo747]

D-K - hope you rode you 2009.

They absolutely rip from mid-top! It's a lite /flickable bike and very narrow - almost like a 125cc 2 smoker. Needs carb modification to main /pilot and one tooth up on rear sprocket. Other than that, this is the best bike I ever rode. Period.

[D-K]

D-K - hope you rode you 2009.

They absolutely rip from mid-top! It's a lite /flickable bike and very narrow - almost like a 125cc 2 smoker. Needs carb modification to main /pilot and one tooth up on rear sprocket. Other than that, this is the best bike I ever rode. Period.

Haven´t ridden it yet! Might be the maiden voyage this saturday...

There is a sand track that is supposed to be open early this spring, and the weather is looking good for the week, but it´s still freezing temps every night...

I´ve already done the rear sprocket and carb jets, look in my garage if you are interested...

A friend of mine rides a 2005 YZ 125, so I know what they feel like!

Only thing is that I feel a cold and sore throat coming... Gotta get better before the weekend now...

[Jonah52]

yeah its no fun riding sick trust me.