'98 GSXF600 Lower crankcase repalcement

[mike_spike]

Hello All,

After a well intentioned idea to replace original steel bolts (holding the side covers) with stainless steel, all was going well until one of them sheared in the lower crankcase...after numerous attempts to get it out, I have a very good example of enthusiasm triumphing over skill and logic. Anyway I'll spare my embarrassment and leave the photos until some other time and get to the point.

I can split the crankcase and try to get the mess repaired OR find a second hand lower and fit that instead...

According to my limited knowledge of engines it makes perfect sense for the crankcase pair to be a matched pair.....is this a fact or are they interchangeable?
I have put a bit of time into what other models use the same lower crank cover and found that the same year (98-03) 750 used the same part.

Assuming the upper and lower crankcase are matched.....What are the risks of fitting an unmatched part? Is there anything I can do (or get done) to the replacement part in order to re-match it.

There are a few other options like buying a complete engine / looking for a matched crankcase pair / replace engine with a bandit 600 etc etc but I thought I'd start with just considering repair vs replace for the lower crankcase.

Regards

Mike

[mektek]

They are mass produced - any mismatch is taken care of by the gasket. So with a new gasket and a part from a nearby year you should be fine. If your engine is otherwise OK you should try to keep it.

[mike_spike]

Thanks very much, that's a big help.

[Lachie]

The crankcase bearings are set as a pair meaning the cases are bored together I would anticipate you could end up with mismatched bearings case should always be paired I wouldn't mix and match best way to end up with spun bearings my guess.
unless you really know what your doing I would avoid mixing the cases entirely unless you get them checked and probably line bored together by an experienced shop.

Take the cases apart and get the thread repaired or helicoiled

[mike_spike]

Hi Lachie,

That makes sense, thanks very much.

I actually came across a matched crank case pair for a reasonable price, so at the moment I have both options open. Once I get the bottom half off I'll see if i can get it repaired and then re-fit. Otherwise I have the new set as a back up.