Cagiva, crank crank clonk!

[Staticam]

My Cagiva motor (some say a Yamaha XT design?) may have lunched on itself. When trying to start it, it cranked and fired for a few revolutions then no more. It's locked solid. The cam chain is still connected and looks ok although the tensioner appears to be at full stretch. I dumped the oil, metal furries on the magnetic plug. I took the alternator side engine cover off and found several metal fragments (maybe alloy) about 2~3mm sized. Removed the starter transfer/idler gear, crankshaft still locked (trying to turn the alternator). The manual says the alternator has a freewheel bearing.

So... has the freewheel died or... your guesses?
I suspect a piece of piston skirt jammed between crank and case. I hope to tear down the engine over the holidays and report back.

[FROSTY:Me]

What model cagiva is it?

[Staticam]

'Tis a '96 Cagiva River 600. Pic's on my home page.

[Staticam]

I removed the motor yesterday. I don't have an extractor to pull the flywheel so I'm taking the donk to the shop to get that done. I had another thought about the freewheel... even if it is jammed, the motor should still turn. I have no idea what's broken, I guess that'll be the Christmas surprise.

[hmmmnz]

any further ahead with the engine?
if you want a hand let me know, you could bring it around and we'll pull it apart and have a look

[CookMySock]

Cool, someone else doing their own motor repairs! I repaired an auto trans the other day (hrm yeah a car one).. I'd never been inside an auto before and it scared hell outa me, but I did it LOL.

Steve

[gammaguy]

sounds like the starter clutch has gone ping.

[hmmmnz]

yeah it does sound likle the sprag clutch has shat itself, normally they just refuse to grip and just make horrible metalic noises, but i have heard of the oval shaped teeth spinning over and jamming as well,

offer still stands if you want me to take a peek

[Staticam]

yeah it does sound likle the sprag clutch has shat itself, normally they just refuse to grip and just make horrible metalic noises, but i have heard of the oval shaped teeth spinning over and jamming as well,

offer still stands if you want me to take a peek

I was hoping to hear back from the shop last week with news of the flywheel pulled, bore removed and possibly the case split, but nothing yet. I've been living it up on holiday so haven't been chasing it up, till tomorrow... Depending on how far the shop has gotten I might have to take you up on your kind offer.

A sprag clutch normally exists where?

[Staticam]

A sprag clutch, dog clutch, freewheel - all much the same thing... but with the starter motor removed the crank should be able to be rotated - but it won't.

Has anyone got a M35x1.5 flywheel puller I can borrow?
The shop didn't have one and couldn't get one from their normal supply.

[hmmmnz]

bugger it, i had one but i left it with a heap of bike bits in the uk
http://www.bits4bikes.co.nz/tools/897.aspx sometimes have them but they look to be out of stock,
it might be worth getting a motion pro one out of the states or uk

[Staticam]

You can't get the one you left shipped over?
I've asked my brother if he can make one, should be doable.
I'll be away for the next 2 weeks but will post again when I get back into it.

[Staticam]

My brother made the puller and I dropped it off at the shop.
The flywheel is now off.
All 4 bolts holding the ring gear and starter clutch to flywheel have sheared! The head of one of those jamming between ring gear and engine case. The ring gear is still jammed onto the clutch. It all looks fixable. I'll have to ask my brother again for his machining skills to tap some new holes into the flywheel.

[hmmmnz]

well that doesnt sound too bad, fixable atleast,
and you dont have to strip down the engine always a bonus

[Staticam]

A tardy reply but none the less here it is.

Along with the sheared bolts the clutch spring was also shagged. Through a dealer a new spring is $50 and in stock (overnight). I ordered it (well, it is the right part) except it wasn't in stock and now it's ex Italy, so order cancelled. I went to the local bearing supply shop to match one out of an oil seal. The proprietor picks up the phone rings someone and says he can get the right gauge but only just over half the length. I order two for $0.50 each! When picking them up the next day the price was wrong... $0.50 for both!!! I dropped them off with the mechanic.

A couple of weeks ago I got the motor back all complete and with the valves set. I put it the frame added oil and fired it up, first time. Ran it for a few minutes, dumped the oil and filter, refilled and went for a twenty minute ride. Before I left the motor was nice and quiet. On return I swear I could hear a ticking sound from the starter clutch area. Figured I'd go and get the puller, take it apart for another look. Before I got that serious, I put the bike on the trailer and took it to the mechanic for his opinion. Well, he thinks I'm paranoid. There is a ticking noise though...

Ah well, only one thing for it, I'll have to go for some rides.