Hi Everyone,

Backstory: Noticed an oil leak under my 95 CB400SF and began investigation. After washing the engine off I could see a bunch of JB weld near the sprocket (corner of the case, not the sump). I've took the engine out and found that at some point someones filled it full of JB weld and had a go at mig alu over the top of the JB weld. It's a right mess.

Issue: I can strip the case back and tidy it up (potentially) but at this point I'm looking for a bottom half of the case or full engine, just in case. My engine number begins with NC23E-18 and I cannot find any cases that match. Some posts on the forum suggest there are differences between the NC23E-10, NC23E-13, NC23E-14 etc which are for the CBR400 etc, that makes sense, I just do not know what values exist for the year/model of my bike. Should I be looking specifically for NC23E-18.

If need be I can also show some pictures of the work from some one who thought this monstrosity of JB weld was a good idea.

Any help or guidance would be greatly appreciated.

Joss

As far as I can remember, any bottom end from 1992 to 1997 will do the job, only the top ends differ. Earlier bottom ends were the CB1 which had gear driven cams, later engines are the completely different VTEC models.

Thank you for your advice. I'll keep my eyes peeled for a donor engine/case.

Wow, has it been that long since I originally started this engine fixing issue? Long story short, I've got replacement cases all prepped but hit a roadblock.

The issue is, I've put my original shell bearings in the new bottom half of the case in the same order as the original. Upon torquing the new case bolts to 24nm I can no longer turn the engine over. If I torque down to 15nm the engine turns but requires some force to. Clearly the issue is the bearing clearances.

I was expecting these to just drop in and not have to go about ordering new bearings and checking tolerances etc. Has anyone had this issue before?

I don't see how the crankcase ID codes or main journal OD codes will help given the case halves are machined at different times and won't match.

Am I going to have to have differenct bearings in the top half of the case vs the bottom half?

Any guidance would be greatly appreciated.

Not sure about CB400 but VFR cases have to be matched to crank using appropriate shells. You have changed cases.

magg wrote: Sun Jul 07, 2024 5:31 am Not sure about CB400 but VFR cases have to be matched to crank using appropriate shells. You have changed cases.

It's the same with just about every ICE engine

When I built my yam fz961 engine and becsuse I put a different crank into another set of cases Measured all the crank main journals I then had a selection of new main shells I found installing these and measuring the ID to be far more accurate than measuring thd new shell thickness and the bare bearing bore and doing the math it was a very long winded process but thankfully a kind family member bought me a portable rattle gun at the end of it all crank spun beautifully and I had a record of new shell colours fitted and where and the calculated new brg clearance some preopld have got away with just using a second hand 1/2 case if it works more power to em !