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Let me preface by saying this bike has been nothing but a headache since I bought it, although I absolutely love KTM.

 

I was riding yesterday and my bike seized up completely. I rebuilt the top end about three months ago but got home and started tearing it apart and found this.....I'm at a complete loss as to what happened as well as what to do next. Any help would be greatly appreciated!

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You mention you 'rebuilt the top end 3 months ago', meaning you replaced :

piston, ring, new valves, guides, valve seats re-cut, new timing chain and tensioner.

In a 8 year old engine, if any of these were skipped well...

 

If everything was indeed mechanically sound, a metallurgy defect or, over-revving could also be considered.

 

If the timing had being off the engine would have been very difficult to start,

and a bend valve would have been more probable than a broken off one.

 

Possible collateral damage, figure your connecting is likely also bent and

if the camshaft design is 'pressed' onto the gear, there's a chance it's spun / out of timing.

Edited by mlatour

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4 hours ago, mlatour said:

You mention you 'rebuilt the top end 3 months ago', meaning you replaced :

piston, ring, new valves, guides, valve seats re-cut, new timing chain and tensioner.

In a 8 year old engine, if any of these were skipped well...

 

If everything was indeed mechanically sound, a metallurgy defect or, over-revving could also be considered.

 

If the timing had being off the engine would have been very difficult to start,

and a bend valve would have been more probable than a broken off one.

 

Possible collateral damage, figure your connecting is likely also bent and

if the camshaft design is 'pressed' onto the gear, there's a chance it's spun / out of timing.

This was very helpful, thank you for your insight. I had a chance to get bring the parts into the local KTM shop and the owner told me the head was for sure toast and he said he wasn't exactly sure what caused it. Quoted me at $1400 for parts so basically now I have to decide what to do with the bike. I've got about $3000 invested into it at this point. Any ideas what to do? Fix it? Sell it as is? Part out? Thanks again

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Apart from the usual consumables which wear out on any bike (chain, sprockets, brake pads etc.)

 

How's the condition of the rest of the bike, mainly :

-has the suspension ever been refurbished?

-chassis, wheel, suspension and steering bearings

in general the 2 things that are most neglected in bikes.

 

I'm not a fan of dumping a lot of money in a near 10 year old bike but, considering the current prices of brand new bikes...

and the fact that trail / off-road bikes get scratched up pretty quickly versus a track ridden MX bike.

 

If the bike otherwise meets your needs, properly refurbishing an older one from A to Z but

pending you can do most if not all of the work yourself or else it soon becomes not cost effective.

Also if you intend to keep it for a long time is a consideration,

if you plan on selling / replace it within the next few years well, you'll never recoup the costs of rebuilding it A to Z.

 

For a while I regretted investing in my CRF versus initially just buying something newer but now for less than half

the price of a brand new one (plus taxes), despite cosmetic dings and scratches, mine is mechanically just as reliable and performs like new.

Plus I don't feel so bad riding in the really rough stuff, never 'holding back' to avoid any battle scars & scratches.

Edited by mlatour

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To add,

If the same type of damage happened to my bike (CRF250X)

having gotten a few seasons of use out of it and,

parts being more expensive in Canada I think I'd sell it off as-is 

and rather invest towards a new bike instead.

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