Okay, I have a set of cases that I am wondering just how bad off they are. Would like some input from people if they woudl re-use them. I still have some more scrubbing and polishing to do, but the last pic is the area that really concerns me.

1. Bottom Cases


2. Top Cases - 1


3. Top Cases - 2 (This is the area I am REALLY worried about)

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Charles Gallant

Is this your RS case?
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james
Its not how fast you go...Its how you go fast.
MC21 Rothmans
RS250
RC31
CRF250X
748R
Porsche (many)
http://members.rennlist.com/j911brick/rennlist3_002.htm

they are RS cases, they are from a bike I bought with a seized big end on the upper cylinder.

My engine is fine, but I would like to possible use these cases to build a second engine to have as a spare.
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Charles Gallant

I know these cases have a life cycle (if you want max performance). If you have a spare used crank (looks like this one is toast) I would sat to slap it together as a spare. If you have to buy a new crank I would say buy new cases as well. I think the motor will run with those cases, but it will be marginal, and you will hav extra risks.
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james
Its not how fast you go...Its how you go fast.
MC21 Rothmans
RS250
RC31
CRF250X
748R
Porsche (many)
http://members.rennlist.com/j911brick/rennlist3_002.htm

I think the motor will run with those cases, but it will be marginal, and you will hav extra risks.

With respect to what ?

The damage in picture 3 is not important, if the case isn't cracked there.
I would worry more about the wear/corrosion ( I can't see what it is) where the bearings are mounted. And check if the cases are true, especially the mating surfaces.

So check for cracks, check if true, check if bearings can be held without rotating, check if bearings can fit airtight, check if the mating surfaces can fit airtight.
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Poul
"If Life Gets Boring, Risk It!"
MC21SE, KISS box
MC21SP, HRC box, racing loom

pbekkerh wrote:
The damage in picture 3 is not important, if the case isn't cracked there.
I would worry more about the wear/corrosion ( I can't see what it is) where the bearings are mounted. And check if the cases are true, especially the mating surfaces.

So check for cracks, check if true, check if bearings can be held without rotating, check if bearings can fit airtight, check if the mating surfaces can fit airtight.

I had already run through the cases to check for cracks, and found none (I was worried about that due to the connecting rod making that mark in pic 3, which means it made contact with the cases). The bearing journals are actually in good shape, the "corrosion" you mention is really sealant that was put in there when the engine was last built. With a little mineral spirits and some 00 scotch brite it comes right off.

I need to check the matting surfaces (as well as the base cylinder matting surfaces) with a straight edge. Overall, I think they will work fine. I plan to clean up that one area so it's a little smoother, but beyond that they should be fine.

thanks
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Charles Gallant

Looks more than useable.

I wouldn't cut the damaged area out. I'd go the other way. Rough it up, drill some retaining holes and epoxy it back to stock dimensions.

Oh, and anyone looking at these pics that has the inclination to modify their NSR cases, just take a look at the shape of the transfer entries and compare them to your "nasty" NSR cases.

Charles, there's a couple of horses hiding in them there cases. Better get your Dremel out

Oh ye... like I need more horses! My new engine is making way more power and comes on hard. Any more and it'll launch me to the moon!

Thanks Matt, I think I will have the journals and matting surfaces measured and look into buying a new crank and build the engine. Keep it as a spare, or sell it and make some money to help reduce the overall cost of buying this second RS

Thanks
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Charles Gallant

charles, I used a set of cases for my NSR big bore engine that had similar damage. Bike has been running great.