NSR125 full rebuild?

[skatefreak]

Afternoon all,
So I have the engine apart,
as expected the crank bearings were buggered (engine was left in a bin bag in a garden for umpteen years thus rusted/weathered, not run to buggery) so new bearings and seals in the post.

I got a second hand crank mighty cheap off a friend and it's pretty tight (lateral play on crank/con bearing) and the gearbox/clutch is in fantastic condition (all parts miles from limits and almost no sign on wear).

Sooo, I was wondering aside from a piston kit, spit shine the cylinder/carb/exhaust, and carbon reeds, is there anything else I should do whilst I'm in there? Am I missing anything?

I'm not looking to invest a huge amount as the engine coming out will be rebuilt as well but I would like to sell one of the engines in the near future and want to be sure its going to last

Any thoughts would be much appreciated.

Best regards

-Jvr

[Vincent]

[skatefreak]

Any idea how much it would be to get the crank checked/balanced?
Will look into doing it myself but it certainly may be worth looking to get it done!

Much appreciation for the suggestion.

Best regards

-Jvr

[Vincent]

You need a good set up to get accurate readings, last one I had checked was dirt cheap but that was at a mates place. An engineering shop shouldn't charge much more than a tenner really. Try find somewhere that works on car cranks, they might be able to check it a bit cheaper. It's worth doing. All the measurements and tolerances will be in the workshop manual. It's run-out and con-rod end play that you're looking for mainly. Luckily for you, single cylinder cranks aren't as prone to run-out as a multi cylinder cranks - which is nice.
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Space Is Deep

[skatefreak]

Cool,
will get onto that.
Conrod play was miles less than the old one and seemed to be within tolerances by eye, will look into checking that closer though.
The run out I have no way of checking accurately to be fair. Will have a call around and see.

Best regards

-Jvr

[skatefreak]

Right,
Crank runout and con rod play are within limits, new bearings and seals going in for the crank shaft.

All the other bearings seem silky smooth, seals seem fine, clutch & gearbox components are well within limits according to the manual...

Is there anything else I should be worrying about for the bottom end?

If not, will get her back together over the weekend

Any thoughts would be much appreciated.

Best regards

-Jvr

[Vincent]

Have you got some good sealant for the cases and given the faces a good checking over for any left over sealent, notches, imperfections etc?

My advice would be to really take your time, it's very easy to rush these jobs. You got the workshop manual to hand?
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Space Is Deep

[skatefreak]

Workshop manual to hand - check.
Have checked and cleaned off all traces of gasket from all mating surfaces, thoroughly cleaned them and have a complete gasket kit for the engine!

The majority of the surface between the halves is absolutely fine however there are a few *dips* at some outer extremities, behind mounting holes if that makes sense. They are pretty far from the inside of the engine gasket material wise.

This being said, I am planning to whip up some JB weld once the bearings are in to bring this surface back to the correct level (assuming it wont cause a problem operationally, it doesn't look great...)



-Jvr