Interesting crank cases.

**Mon Sep 10, 2012 5:31 pm » Post: #1 » Download Post**

I've been digging through my ever expanding collection of NSR parts, and I have 2 sets of mc18 cases (and 1 complete bottom end). I was looking at the flowing of them, and noticed one of them is quite different;

Any ideas?

Paul
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More **** two strokes than you can shake a **** stick at.

**Mon Sep 10, 2012 5:47 pm » Post: #2 » Download Post**

A modification that was used back when, similar to early '90's RS250's.
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If I have to take the carbs off once more...

**Mon Sep 10, 2012 5:52 pm » Post: #3 » Download Post**

Thanks Stephen, so they should work ok?
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More **** two strokes than you can shake a **** stick at.

**Mon Sep 10, 2012 5:53 pm » Post: #4 » Download Post**

Yes, though depends a little on the size of the crank fitted.
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If I have to take the carbs off once more...

**Mon Sep 10, 2012 5:56 pm » Post: #5 » Download Post**

Please expand!
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More **** two strokes than you can shake a **** stick at.

**Mon Sep 10, 2012 6:03 pm » Post: #6 » Download Post**

There are a number of different diameter and stuffed cranks. These must be matched with the cases. You may find the internal diameter of the cases differ to other models.

For example R2J cases are bigger than R5K, which in turn are smaller than MC21's. However HRC cases are smaller again and use a smaller crank but which is stuffed.

Cutting away such large amounts internally often requires the use of a different crank to get the maximum benefit.

Personally I think the best crank cases for an NSR250 are MC18 R5K (modified) fitted with a HRC F3 crank.
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If I have to take the carbs off once more...

**Mon Sep 10, 2012 7:48 pm » Post: #7 » Download Post**

Thanks mate, so where do I find one of these cranks then?
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More **** two strokes than you can shake a **** stick at.

**Mon Sep 10, 2012 7:56 pm » Post: #8 » Download Post**

Try Andy, if not Dan Williams.
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If I have to take the carbs off once more...

**Mon Sep 10, 2012 8:47 pm » Post: #9 » Download Post**

Cheers, will do!
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More **** two strokes than you can shake a **** stick at.