Belt Tensioner Slipped: Should I attempt to rebuild a blown 900ss engine?

I had a pulley come undone and shred a belt at 90. Bent valve only damage.

 

Some people Loctite the tensioner bolts.......

........as to whether it is right or not, I wouldn't criticise anyone that did. Likewise I wouldn't say that 'bl**dy tight' is wrong.......

.........however, having suffered from wrung allen bolt heads in both cases, I just use 'bl**dy tight' as when it comes to drilling the heads off, it is much easier to get the stub of bolt out when it hasn't been Loctited.

 

Assuming that the engine came to a rapid halt and that it has not been used since, then I guess options are:

- take the plugs out, valve covers off, belt covers off and try delicately to see whether any damage is obvious - ideally one would use some sort of laporoscope to look inside the cylinders.

- Perhapss even try refitting Belt(s) and tensioner correctly and seeing whether the engine will turn with plugs out, or even run with them in

- But, realistiacally, I'd say the heads need to come off in order to check the pistons and valves. So options for DIY are to try doing that in situ, or to remove the engine and take to an expert.

I have to say that if I had never stripped the top end of an engine before, I would prefer not to start with a Ducati or a V-twin!

 

Engines come apart real easy, it's rebuilding them that isn't so.

 

Take pictures as you go .....write down what you have done so you can retrace your steps

 

If it were me in the same position, I would take the plugs out and the belt covers off, then re-adjust the belts. Then I would either use the crankshaft turning tool (which I don't have) or use the silly nut socket for the cambelt pulleys and turn the engine over slowly; listening and feeling for problems.

I would also try to look through the plugholes where I can, to see if there is anything obvious there.

If none evident, I would fire it up and see what happens.....after all, if damage has already been done, then the engine would have to be dismantled anyway.

In the OP's case, a tensioner may have allowed a belt to slacken, but it may not necessarily have been enough to cause damage.....Gates Technical advised me that belts should be under some tension when cold to avoid tooth jumping, but even so, I think it would have to be pretty slack for that to happen..........hopefully the OP's engine was hot which might have been enough to keep some tension on the belt.

 

Start off by taking the plugs out and gently rotate the engine until the relevant piston is at the bottom of it's stroke (without the damaged cylinder's cambelt in place), then turn the camshaft by hand, if it turns a full revolution you may be lucky, if it sticks you'll have done some damage.

 

give it a go. its only nuts and bolts.

 

if you want you can buy my engine. 3.5K and i'll throw in the rest of the bike for free

 

This is what I was thinking of as a way of peering in through the spark plug holes:

36 inch Endoscope | Frost Auto Restoration Techniques

Unfortunately over £200 and out of stock - but might be worth looking around - maybe you could rent one, or if you know a friendly surgeon perhaps....

 

remove the vale shim covers, that will learn ya.

 

Try: Dart Snake Scope [510-100] - £36.00 : Dart Systems Limited, Industrial Endoscopes, Borescopes, Inspection Cameras, Pipe Cable installation tools equipment. need a laptop but works for me.

 

Sorry, meant to add it's not flexible enough to see the valves but you should be able to see any witness marks on the piston crowns.Mike

 

I have a 10mm wide by 100mm long mirror Araldited to an artists paintbrush handle..........half the handle to hold and the other half to reinforce the mirror a bit.......

...........stick it in the hole and use a Maglite on the mirror outside the hole.......it's fairly handy if you can figure what you are looking at....

 

They are a pretty easy engine to work on.
I would take the head off the side that slipped and check it that way to be sure.
I had the nut come loose on one doing about 70 and it made a complete mess of things, snapped the exhaust valve which then embedded itself at right angles into the piston and then happily hammered a very large lump out of the head, whilst the rest of the bits scored the bore, but that was a pretty easy fix(bit pricey though). new bore, second hand camshaft, valve and piston and the head was repaired (welded and re-machined) I put it all together and sent just the lump to the local dealer to setup (I am more confident now and would do that myself as well)
What year ss is it ?

 

Sell it to me if you don't want to do it :wink:
I have been looking for one that needs work for ages

 

There's nothing to be scared of is all I can say about working on Ducatis.
If it went bleeeeeuuugghh and lost power then sure you're into new valves and probably guides.
If you do strip it and don't want to continue at least you've saved some time/money at the dealers.