There's a (GAPING) Hole in My Motor, Dear Liza, Dear Liza...

[Embyr]

Actually, it's in my belt cover- (and my timing belt is snapped) but god knows what happened in the motor itself...  I'm wondering if anyone has any suggestions as to possible causes/ways I can prevent this from NOT happening again on the replacement motor (and yes, I actually found one at a decent price, thank you italian-bike-gods!)

I was at Willow Springs (Big Willow track) in SoCal when this happened...  session 3...  this is a 2001 M900, I've had her for 2 years now. And no, I wasn't redlining the crap out of her- also, there was definitely enough oil in the bike... that was not the cause. (Glad there was no oil on the track- coulda been bad!) I'm glad it happened in turn 6/7 because by the time I *nearly* reached the track exit it had died completely...  wouldn't (and still doesn't) start. Had it happened in turn 2 or something it might have ended up far worse...and at least I kept her upright.   Sucks, too, because I had awesome new tires I was enjoying and I was really having a blast out there.
I'm attaching a pic of the hole.


I started to hear a buzzing and then a clunking sound, as all my power left very quickly. Did something happen with the pistons? Rods? Any other ideas? I'm really mechanically disinclined (sorry!) but any ideas as to what may have caused this are welcome... as well as how to avoid another engine ''spontaneous ventilation problem" on my next motor. Thanks all...

[cduarte]

since it's an interference motor, you probably have bent valves in the head that was affected. There's really no need to replace the motor, you should be able to repair what you have fairly inexpensively. As far as the cause, it was most likely an old belt that was far beyond it's useful life.

[Embyr]

^ i don't need to replace the motor???  one of the top mechanics (wsmc racebike builder) who has my bike now assured me that i need a new one...  :/   should i really bring this up to him?

[cduarte]

read this thread... http://ducatimonsterforum.org/index.php?topic=9909.0 The bike in that thread had a 4-valve motor, one of the belts failed, and the only damage was to 2 exhaust valves... Replacing the motor in your bike would be overkill unless the motor is really trashed, and I doubt that it is.

[Ddan]

You *could* have trashed the motor, but it's not a given.  Bent valves for sure, possibly damaged head and/or piston.  If the head and piston took a bad beating you could have damage to the cylinder walls, and in the worst case scenario you dumped shrapnel into the bottom of the motor.  Check all the belt pulleys as that is probably the whirring you heard before the belt broke.

[Langanobob]

but any ideas as to what may have caused this are welcome... as well as how to avoid another engine

Seems like most of the time, belt failures are caused by belts that have been tightened too tight, causing the tensioner bearings to seize up and in turn breaking the belt.  They can also break from miles/age but there's a lot of safety factor built into the maintenance schedule.  Do you know how long it's been since they were changed or adjusted?

Best way to prevent it in the future is to make sure they are properly adjusted and change them according to the recommended maintenance schedule.  Also, when you repair or replace your motor, also put new tensioner bearings in it.

[Slide Panda]

I'm with Dan - you should do some inspection before you commit to a new engine. Yours is not the 1st Monster to loose a belt and live again w/o a full transplant.

You'll probably be looking at:
New valve and guide
New piston

Less likely but still quite possible:
New head
New barrel - or a hone and re-plate of the existing one.

Those are the big items... OF course there is the possibility that other elements like the rod got damaged. But those are a lot less likely. I nmost cases like this damage is restricted to the top end.

[Speeddog]

As others have said, you *might* need a new motor, but not necessarily.

[Embyr]

Thanks for the replies...  I e-mailed the mechanic who has assured me (but without much mechanical backing) that I *need* a new motor, and put in some of your suggestions...   

The other thing to consider- the motor I'd be getting has only 12k miles (my bike has almost 23k) and I'd be getting it for around 900 bucks. What with the work that might be involved in fixing bent valves/pistons anyway- would it just make more sense to buy the new motor @ that price?

[needtorque]

Still have to pay the guy to swap the engines which will be a lot of labor charges.  Think of it this way.  If you do a lot of track days could the mechanic, who sounds like he might be a bit fishy, repair the current one and do some mods while he was at it. 

For instance, if there was a hole in the piston as a result of the interference from the valves, could he put in new overbore and high compression pistons and fix the valves for a bit more than the 900 you are already going to spend on a USED engine with unknown maintenance history?

[cduarte]

I'd find a new mechanic...

[Bladecutter]

Embyr,

In the two years that you have owned your bike, have you ever replaced or tightened the cam belts before you did your trackday? If not, there's the reason why your belts broke. They need to be replaced every 2 years, and tightened every 6k miles, if not more often, depending on how you ride the bike.

BC.

[Embyr]

i replaced the belts at my last 18k service...  like I said, I am NOT mechanically inclined, so I have not done any of this work myself. And this guy is really not fishy- like I said, he builds WSMC bikes and knows his shit.


ok, i'm very confused by this whole thing. i distinctly remember being told i needed a new motor, but whatever.

so my 2 options are: leave it with this guy (who knows me and will make time for my bike, and is williing to put in a new motor) and skip the hassle and just buy a new motor w/ half the miles of my bike @ 900 or less, 300 to install.
OR- take the bike to a very busy duc shop where the mechanic is not willing to swap motors if need be, is notoriously busy, but might end up saving me $ if i didn't actually need a new motor?

What should be the determining factor here?
OR- should I just go ahead and get the new motor anyway if I can bargain down the price past a certain figure?

[Speeddog]

$900 for a motor is a good price.
$300 for install is a good price.

Assuming, of course, that you get to keep your old motor.
Even being hurt, it's still worth some $.

[erkishhorde]

Swap the motor and fix the old one and then sell it to try and recoup the cost of buying a new motor.