Engine suddenly siezed???...

Alright guys, I'm gonna throw this one out there and see if you all can give me some ideas...

Last night it was so nice out that my buddy and I decided we'd go out for a ride. I engaged the "choke" and started my bike. starts right up. I let her idle for a few mins, slowly disengaging the "choke" lever as time goes on. I decide to see if she's warm enough to run on her own yet and completely disengage the lever. she dies out. no big deal, right? i'll just start her back up...

this is where my problem begins...

I hit the start button and can CLEARLY hear the STARTER (not just the solenoid) engage. ony think is, it's not turning the motor over.

That's odd... but it gets better.

the headlight looks a little dim, s i figure maybe my battery is too low to turn it over (maybe time for alt. brushes). So my great freaking idea is to push start it. I ive on a hill so I decide to set the fuel to prime, coast down the hill for a few (up to about 12MPH), and dump the clutch in 1st.

I've done it before when in a pinch, why should this be any different?...

well she doesn't start, instaed, THE REAL WHEEL LOCKS UP!!! the motor wouldn't even turn.

we pull over and throw her on the center stand. pull one of the plugs and look for water/gas (hydro-locked?) nothing in cyl-1 (didn't check the rest yet). tried to see if we could spin it backwards using the wheel, nothing. It seems that something in the motor has locked up and won't allow it to rotate anymore.

WTF?

So i began to push it up the hill, which seems a LOT steeper when yu're pushing a 550 lb bike up it. turns out the task was a little too much for me and i almost passed out (can you say "out of shape"?) my buddy rode up to my house and him and my father came down to help. we got it home, i drank some water and sat down for a bit, and didn't even want to look at the bike till today.

Any ideas guys? I'm usually good at coming u with theories for stuff like this but i'm at a bit of a loss.

my only two theories...

1. hydro-locked

2. something with the starter clutch?

 

Pull all plugs, left timing cover, roll the motor backwards (clockwise) with a wrench, and cross your fingers.

I'd say "no" on the hydro-lock.
Maybe on a broken chain guide ?

 

ya, i didn't really think it was hydro-locked. that was kind of a reach. i was thinking about the chain guide too, i didn't replace it (like i should have) when i did the motor. i'll try rotating the motor in a little while.

 

pulled plugs, rotated engine with a wrench. it turned backwards almost 2 revolutions. i can move it back and forth fr those two revolutions so i'm almost thinking valve interference at this point. maybe the chain jumped a tooth? a piece of the chain guide still makes sense too.

i'm still welcoming theories/suggestions.

 

i'm gonna borrow my buddy's snap-on digital bore scope in a couple hours and take a look at the valves/pistons. also, the 'interference" seems to happen at TDC.

 

Bummer man. Sounds like valve to me too, which really is sort of a good thing. Hopefully you won't have to pull the whole motor... you just went through all that...

Maybe now you'll have some time to clean my carbs for me. lol.

I found a nice 100cc moped on craigslist, you'd look fabulous on it.
It's pink. And has tassles

In all seriousness - good luck with the boroscope. Hopefully (sort of) You'll see a big nasty bent valve. Give me a ring if you want that moped

 

Wow No mercy - a pink moped - LMAO

Hope it's nothing too serious

 

Haha, I would have done the same to him.

 

TWO revolutions? Wonder if a spit shim can lock a motor... I'd pull the cam cover too, plus then you can watch the valves open and close or try to...

 

It takes 2 revolutions to rotate the cams fully...

 

ok, so i've got the scope (bad-ass little thing) but i can't check it right now. I spent the day installing HID's in my car (yay!) and now i gotta help my friend move. I'll check it tomorrow.

 

HID's in your car... how bout a new clutch, or maybe your 3rd transmission?


Maybe if you knew how to shift, you'd be on your original trans in the car...

And maybe the bike would still be alive!

lol... jk!

My money is still on the cams... chain, valve, bucket, shim, something.

I can imagine a shim spit out might get caught where the motor will turn both directions but only so far... I think you would have heard somthing first if you skipped a tooth and bent a valve. Then again, never heard it myself lol.

 

You need to stop !!!
You are going to break something expensive without further help or further die-assembly.
If you can't go 2 or 3 revolutions backwards, something is very wrong.
And i can't help you !!! Somebody else please help. . .

 

Can you spin the real wheel in neutral? just to rule out the transmission.

 

As stated in my original post, I tried to spin the rear wheel while in gear, and I rolled down the hill in neutral. I'm nearly positive it's not a trans issue.

 

Could be valve issue but chain guide seems to be a cocideration. Pull valve cover and see whats up nothing there then pull the pan.

MN

 

That's pretty much the plan. Weather looks less than ideal tomorrow so I'm not sure if I'll be able to do anything... :-(

 

i looked inside her using the scope. i saw no signs of damage and everything seems to move freely. i still have to take her top off and have a look around the cams before deciding on exploring the low end.

isn't suggestive writing fun?

 

Holy crap is this due for an update!

So I pulled the valve cover off and found 0 signs of damage. everything looked good, until i noticed a cam sprocket bolt missing... I know they were on there before!

Well I grabbed the Snap-On digital bore scope and went to town. I ended up finding (after pulling one of the cams in order to move the chain out of the way) the missing bolt. It was wedged between the chain and the head. when i rotated the chain, it would ride up with it till it stopped on something, and the same going down also.

I removed the BADLY damaged bolt and scoped around for any more possible damage. All clear!

So put the cams back together and attached the cam sprocket with only the one bolt (temporary, not gonna run it like that). Got my valve timing all set and rotated the motor by hand a few revs. All clear. Went backwards, all clear. inspected the chain closely, all good. set the auto tensioner up and put it back in place. rotated back and forth to remove slack. all set.

So now i just need a bolt to replace the f-ed up one I pulled out.

How did this happen, you ask?

Well, let's just say, if you ever work on a motor WITH someone else, don't assume the other person torqued anything. Occasionally, you both assume this very thing and end up a little screwed.

On a side note, I lost my freaking key! It was my only copy!

 

That reminds me, I gotta go get some spare keys made up =p

 

haha, ya. good idea. i think i'll have to take the ignition switch to a locksmith and see if they can make me a key.

 

Get the right blank and the number off the bottom of the switch and a real locksmith won't need the switch itself.

The locksmith I went to got a little miffy because I brought key blanks with me (assuming he wouldn't have them-- he did.)

 

that is assuming all "real" locksmiths will have that database for the old yamaha keys at hand...