Bikesure_adrianflux

Make your own Case Saver

bazread said:
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.
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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?...:chuckle:
 
jonzi said:
Have you ever cleaned that chain?
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Whadya mean, that is clean, you can read the writing now. Darren69 shamed me into sprucing it up :)

Mr Gazza said:
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.

....
....
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All getting a bit complicated.! It might just keep the chain out of those holes though?
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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 :)
 
Dirty said:
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 :)
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Yes, that is clean compared to before and oiled as well. I suppose I better do mine now! :)
 
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.
 
bazread said:
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.
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You missed out on the one I put in the for sale ads on here last night, titanium and only a tenner! :banghead:
 
utopia said:
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.
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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.
 
Mr Gazza said:
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..!
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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.

eugih4.jpg
 
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RossObey01 said:
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.
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I wouldn't trust aluminium especially that thin, if the chain should break and 'catch' the ally it will then bunch up into it. Consider the power/speed that the chain could be going at - it's most likely to break on full power.

Might help? but stainless is much stronger and harder so far less likely that the chain will catch it.

Get the ally part to fit and then use it as a template for the stainless. :thumbsup:
 
An ally case saver is better than no case saver and will probably work in a % of situations but SS would be preferable.
 
Oh great another fun little thing to fabricate and tinker on in the garage! Ok now where to get a small piece of stainless steel...
 
Nice work so far Ross..:thumbsup:

Mild or stainless steel are favorite materials. 1.6mm thickness sounds ideal.

Not sure I would trust ally myself, but it might work?

It will be nice and soft and easy to bend as a pattern, so nothing lost.

Bear in mind that the 5 speed 750 cases differ from the 6 speed 900's, so be prepared to make some alterations as my pattern is for a 900.
I am given to understand that it's a bit tighter inside the 750 and more so on the 600, so if you find that the pattern needs some significant changes please post them on here if you can find something that works.

You may have also noticed that on Dirty's 'saver on an earlier post here, that his tabs are staggered...So something else to look out for.

Good luck...:biggrin:

(P.S. Just noticed that this thread has become sticky...Cheers Rob?)
 
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Sorry about that. I'm afraid after 5 years I can't find any trace of it, but the actual saver is still doing sterling service.
I will hoik it out for a clean today and try and re-draw it.
 
And while this thread is active, I'll add a note on fitting a saver to 750 cases.
This applies to later type 750 cases with external clutch slave.
I managed to squeeze a proprietary case-saver behind my std, 15T gearbox sprocket but it was damn tight.
Occasionally I reckoned I could hear the chain scraping the saver when the engine was on the overrun and the top run of the chain was slack.
Witness marks on the saver confirmed this.
However, I decided that it wasn't a major issue and left things as they were.
Then last year, as I was about to set off for the TT, I noticed a couple of shiny,worn areas on the chain where the saver scraping had been most severe .. possibly due to a minor tight spot in the chain, even though the chain was generally in decent condition.
Having no time to investigate further, I crossed my fingers and set off for the Island.

Luckily, when the chain snapped I was only 50yds from my tent at Kirkmichael. :eek:

I have since resorted to fitting a 14T gearbox sprocket and there are now no more clearance issues between chain and casesaver.
In the light of my experience I would not recommend fitting a casesaver to late 750 cases if the std 15T sprocket is retained.
 
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