Gen 1 v Gen 2 Crankcase



ARES6

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I have just damaged a gen 2 crankcase and have been offered a gen 1 crankcase. Can a gen 1 crankcase be fitted to a gen 2 engine and are there any issues that arise from this change?
 

Boosted Cycle Perf

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I have just damaged a gen 2 crankcase and have been offered a gen 1 crankcase. Can a gen 1 crankcase be fitted to a gen 2 engine and are there any issues that arise from this change?
As long as you’re using just the cases everything will swap over. The only major difference is the crankcase breather is slightly different between the two. That’s not an issue though.
 

Berlin Germany

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Thank you for your advice. It makes my repair much more affordable.
another little hint

foreword:
some 2 or 3 years ago my brother and me replaced, at a gen 1, the lower part of crankcase only!
(the owner have had an accident and a piece of crankcase was irredeemably broken out)

but we had to messure (with plasti gauge) all crankshaft´s bearings and replace the "old" ones by 5 new pairs
(in this case thicker bearings)

by doing so we saved the lots of time to diassemble cylinder etc. (for replacing both parts of crankcase)

result: this (our) very first "TEST"! was absolutely successful and the gen1 runs again like new.

according to "Boosted..." the dimensions of the two crankcase parts should be identical / the entire transmission of the gen2 should fit 1: 1 into the crankcase of the gen1
remember (so far i know) the gen2´s transmission shaft to front sprocket is a bit longer than the gen1´s shaft.
(take their both lenghts and you should be astonished)
so - if you don´t replace this shaft there is no chance to get the chain "straight lined" onto the front sprocket.

here my idea ( ;) ) :

if this replacement could also work fine,
if you put e.g. a lower gen1 crankcase to a gen2´s upper part ,
no one knows
and no one could guarantee.

and even if you do a replacement (like us) with now only gen2 parts, no one could guarantee a full success.

this try only wastes your time
but not a lot of money - i guess !
 

Berlin Germany

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It’s a terrible idea to mix cases, even of the sam generation. They’re machined together, and need to stay together as a pair.
yes - in principle you are 100% right!
(what i wrote - no guarantee)

but sometimes it just works (contrary to all experiences and statements)

we tried and fortunately had no error ;-)
 

ARES6

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yes - in principle you are 100% right!
(what i wrote - no guarantee)

but sometimes it just works (contrary to all experiences and statements)

we tried and fortunately had no error ;-)
Berlin, Germany. I am surprised that you have been able to make the different upper and lower halves work. So maybe, you were just lucky that the differences in alignment of the top and bottom halves were minimal.
 

Kiwi Rider

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Berlin, Germany. I am surprised that you have been able to make the different upper and lower halves work. So maybe, you were just lucky that the differences in alignment of the top and bottom halves were minimal.
I also wondered how that could work with different case halves... being that the cases are align bored bolted together at the factory and the chances of 2 different case halves matching are slim to nil.
 
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