Make your own Case Saver

[Dirty]

Originally Posted by Mr Gazza

Sorry to hear it's being such a pig Dirty.!

Well done for persisting with it.

It sounds like the 600s and 750s are very tight in there. On my 900 the tightest place is against the clutch pushrod housing too, but I am getting a good 3mm or so I would say, with the guard hard against the case at that point.
Utopia has mentioned that his is tight on the 750 aswell, but he runs it okay, can't remember if he said there was a witness on the guard or not?

I guess if it rubbed all the time it would be a bad thing, but the occasional touch should be okay.

I reckon I've got 2mm in total, with the saver in it's down to virtually nothing.

I'll stick it back in one day then run it round the block a couple of times, check it, couple more times, check it, to see how things shape up when left to themselves

[Dirty]

Stuck it back in today and did a few miles. Nothing exploded or went bang so far. Will leave it in for a few more then have a look. I think it will be ok though. Might not be perfect but it will give some protection.

This is the gap I had to work with.

[jonzi]

Have you ever cleaned that chain?

[rollo22]

Originally Posted by bazread

If anyone is up for fabricating a spare case saver for the 1100 Evo, I would happily buy one as I do not have any skills when it comes to this sort of thing.

I reused the one I had in the S4RS needed a bit of modding with the Dremel.

[Mr Gazza]

Mmm... It's tight alright.!

Ironicly there seems to be plenty of room either side of the pushrod boss...And that is where the chain would bunch in the event.

I am pondering an embryonic idea... Just wodering if it would be possible to have two guards in there?

One going as far as the boss from the top, and thinned down over the boss. and another below, picking up from beneath the top guard, ie, overlapping a bit. (or underlapping).

Each guard would need two mounting points each, I was wondering if it would be possible to use the clutch slave screws?
This would imply the use of a washer under the third slave screw to level things up, and probably a little spacer in the slave too, for the pushrod..!!!

All getting a bit complicated.! It might just keep the chain out of those holes though?

[Mr Gazza]

Originally Posted by bazread

If anyone is up for fabricating a spare case saver for the 1100 Evo, I would happily buy one as I do not have any skills when it comes to this sort of thing.

If an S4RS one fits an Evo within a little, then maybe it's not too far differrent from an M900?

If you spend a few minutes playing around with some card or plastic, based on my drawing, you might come up with something that works after a few attempts.

Once you have an accurate pattern, all you have to do is get someone to cut and fold it for you in metal.... Gotta be worth sacrificing a Corn Flakes box?...

[Dirty]

Originally Posted by jonzi

Have you ever cleaned that chain?

Whadya mean, that is clean, you can read the writing now. Darren69 shamed me into sprucing it up

Originally Posted by Mr Gazza

Mmm... It's tight alright.!

Ironicly there seems to be plenty of room either side of the pushrod boss...And that is where the chain would bunch in the event.

....
....
..

All getting a bit complicated.! It might just keep the chain out of those holes though?

Well the case saver is in now and should do that job even bearing in mind the 2 deep score marks the chain will have inevitably cut in by now

[Darren69]

Originally Posted by Dirty

Whadya mean, that is clean, you can read the writing now. Darren69 shamed me into sprucing it up



Well the case saver is in now and should do that job even bearing in mind the 2 deep score marks the chain will have inevitably cut in by now

Yes, that is clean compared to before and oiled as well. I suppose I better do mine now!

[utopia]

My cases looked every bit as tight as that. And with the same nasty hollow just waiting for the chain to bunch up into.
Makes you shudder to think of it, eh ?
I was seriously surprised when my current saver fitted so well, and the chain doesn't rub at all when the wheel is turned by hand.
When I come down to the bike shed show Dirty, you can try mine for size in your cases if you like.
I might even make a copy in stainless (mine's plain steel) so perhaps I could make two if it'll fit your cases too.

I gave much thought to fitting a thinner saver in there, including a two-part design and various other crafty schemes, including a couple of prototypes (one of which I'll also bring along, just for interest's sake), but I never came up with anything satisfactory.
Lately I've been wondering how well a thin one would work if you could fill the space behind it with some kind of epoxy resin or somesuch....fixed to the saver but loose in the cases (via pva release agent on the cases before smearing the epoxy in there and seriously hoping that it didn't stick).
I don't believe that the hammer from the broken chain is the main problem, but more that the chain can lift off the sprocket, bunch up and jam. So maybe such a scheme would be adequate.

[Rally]

Originally Posted by bazread

If anyone is up for fabricating a spare case saver for the 1100 Evo, I would happily buy one as I do not have any skills when it comes to this sort of thing.

You missed out on the one I put in the for sale ads on here last night, titanium and only a tenner!

[Dukedesmo]

Originally Posted by utopia

I don't believe that the hammer from the broken chain is the main problem, but more that the chain can lift off the sprocket, bunch up and jam. So maybe such a scheme would be adequate.

Indeed, I believe that this is the problem. Even a thin plate will work fine as all it needs to do is keep the chain on the sprocket for a maximum of 100 links or so, after that it's job is done.

The damage comes from the buildup of chain that can't escape and gets rammed into the soft crankcase at huge force/speed.

Gutted Rally !!

[Capo]

Originally Posted by utopia

I was seriously surprised when my current saver fitted so well, and the chain doesn't rub at all when the wheel is turned by hand.

That case saver came from here http://www.desmotimes.com/

[Albie]

Originally Posted by Mr Gazza

Pleased that I have inspired at least one person..

Let us know if those measurements work for you..And how the Stainless bends.

Can't apologise enough for the way the drawing has reproduced. I converted it to a pdf, hoping that I could post it in a printable form, but I then had to convert it to a jpeg to post it.
That was with tinypic...Anybody know how I can post up a pdf so it will be printable from here?
Ideally I would like it to be printable at 1:1 so that it can be cut out from the print and tried.
But I can't even seem to get it to pdf at 1:1 from TurboCad...Doh..!

Got 2 to make. M900 and a Scrambler version.

Thanks for pointing this thread out Gazza, I knocked one up at work from a sheet of 1.6mm alu. I'm not sure it will be up to the job though? I don't do a lot of metal work, so didn't appreciate just how soft it was. Still, it only took 30 mins to knock up, so I'll test fit it to the bike and if it's good I've got a sheet of 1.6mm stainless here, too.

Any opinions on if aluminium will be good enough? It's not got to take much impact, especially on a 750, it's just a guide.