Motorcycle Repair/CBX 1978


QUESTION: Hi I have a 1978 cbx the bottom case is no good I know the bottom and top cases came as a pair but what are your thoughts on me putting just the bottom from another engine on mine?.
I have just had my engine fully done up and don't want to have to get the whole thing redone again $$$$ what are the pros and cons of using the bottom case from another engine cheers Steve.

ANSWER: Sorry to be the bearer of bad news Steve,  You cannot use a mismatch like that, since the cases are line-bored and sized, you will not likely be able to get the crank to seat properly and thus your engine would not run right and not last long...  Replace both cases, and do the job correct.  Why is just the bottom case bad, can it not be repaired?


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QUESTION: Thanks Jan it had been repaired in the past by another owner it looks like it had been down the road and holed the repair is at the bottom end were the cap screws on with the three screws also one of the lower screws has been stripped and repaired with a helli coil I think when they drilled it for the helli coil they drilled to far and went into the crank because oil comes out of that screw hole as well as out were the cap goes on cheers Steve

I think a good welder will be able to tackle that repair job without too much of a problem, allowing you to re-use your original case.  You will probably have to remove the case and make sure it is clean before that repair is attempted.

Good luck,  Jan

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Jan Ringnalda


PLEASE NOTE: PLEASE READ THIS!!! I can help with questions ONLY on any Honda CBX-1000 motorcycle, only 1978 to 1982. OR 1981 to 1983 Honda CB1100R models ONLY Honda CBX/CB1100R motorcycles, Please NO other makes, no other models. IF YOUR QUESTION IS FOR ANY OTHER BIKE Your question MAY BE FORWARDED TO THE QUESTION POOL WHERE IT MAY NEVER BE ANSWERED. IF I ANSWERED YOUR QUESTION, and you feel the need to give me marks lower than 10, first post a follow up question. If you mark me lower, I will respond and you run the risk I will never, ever, answer one of your questions again. I'm doing this free of charge, as a service to fellow motorcyclists. If you do not value my time, I do...


Have owned over 50 of these fine classic Honda motorcycles

International CBX Owners Association, SAE, Materials Research Society

CBXPress, VLMC magazine, Used Bike Guide

PhD in Materials Science, Post-Doc in prototyping automotive components

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