Matching cases - does it matter?

[Nathan S]

I've got a DT175 engine here, with a shitty LHS engine case (chain damage, corrosion, and some damage from where a ham-fisted idiot [me] was a bit rough when drilling off screw heads). 
I want to use the RHS case from this engine to get the correct engine number for the bike.
I have a good 'spare' LHS case.

Is it OK to mix and match or not?

[Hoony]

Short answer is YES.

i have done this with a few bikes over the years, and i did do it to a 1980 TT250 Yamaha

[yzhilly]

Yeah i mix and match yamaha cases all the time and if there the same Serial # range it shouldnt be problem

[firko]

Nathan...In theory it isn't advisable to mix'n'match cases as they're machined in pairs at the factory . I can remember reading an article explaining the machining process which went on to compare the tolerances between miss matched case halves. The resulting difference in tolerance were quite a surprise. That was probably 30 years ago and now with improved manufacturing techniques including CNC machining I doubt that there'd be much of a problem. But...we are dealing with old bikes aren't we? In the end, it probably won't matter that much.

[paul]

nathan i had a crack in a 490 maico left side crank case i had a spare set so i just used the other left hand one no problems no leaks seems fine

[vandy010]

are they the same colour?

[paul]

what colour got to do
with it

[Snowy 76]

Think Vandy was having a Dig

[caps 999]

yeh no probs i bought new cases for the 250 j got every thing except for rh centre no probs there

[lms6201]

 mix n match seems to be the go , i know 490,s aren,t even listed as a pair ,when i bought the wr one ' capps were the 250 ones listed seperatly as well ?  u would think if they are matched up they would only be sold in a pair 

[caps 999]

i work at a bike store down here in melbourne ive never seen a parts listing that list centre cases as a pair there always sold seperatly

[Nathan S]

Thanks gents.

 

Vandy, one will be black and the other will be green with yellow polka dots... 
And to give the serious answer to the non-serious question: Raw aluminium.

[pancho]

I've got a DT175 engine here, with a shitty LHS engine case (chain damage, corrosion, and some damage from where a ham-fisted idiot [me] was a bit rough when drilling off screw heads). 
I want to use the RHS case from this engine to get the correct engine number for the bike.
I have a good 'spare' LHS case.

Is it OK to mix and match or not?

i had a problem back in history with  a very fast tiger 70 [250 triumph] which kept on machining tram tracks on one side of the barrel till i woke up to the fact that it had unmachted crank cases;lesson---if you use odd halves make a nice fitting mandrel to fit the small end and ensure that it is dead parralell to the top surface of the crankcase. cheers wally