NSR250 engine rebuild

[plutoniumman]

Okay my engine spilled its guts. Check out the carnage.

Carnage

This is from one piston only. The other is fine. Clearly the barrel will need some replating. I will contact them Te Puke dudes to see what they can do. Any other comments? How does that head look? Salvageable?

[Sketchy_Racer]

Mmm YUMMY

That barrel looks fine. as long as there are no cracks through it, it should replate just fine. When you get the barrel back make sure to use a bit of 600grit or similar sand paper (dip it in oil too) and just give the edges of the ports a clean up.. don't want the piston ring catching on them now eh.

also, when you get it back, clean it right down with brake clean and keep wiping the bore with a white rag or tissue untill you can't see any residue on it at all (this may take a while) once thats done, get a bit of two stroke oil (the same the bike runs on) and rub it into the bore.. again after that wipe it clean.

Now, remember to find out WHY it did this. given the color of your piston, it looks very lean.. Why is that so? Has one carb got a fuel block? air filter fell out?

[centaurus]

This is from one piston only. The other is fine. Clearly the barrel will need some replating. I will contact them Te Puke dudes to see what they can do. Any other comments? How does that head look? Salvageable?

I have a similar problem on a MC18. In my case the barrel and the cylinder head for the top cylinder need replacement too.

I asked Honda and looks like they are not producing the parts anymore. Where could I find a topend kit (pistons and rings)?

Also, what can be done with the cylinder. In case I find a second hand one to buy, does anybody know if there are different types for different types of MC18 or any MC18 barrel would do?

P.S.
Plutoniumman, if you think I'm hijacking your thread, let me know and I'll back off .

Thanks

[imdying]

Have you tried Tyga? They make 300cc kits (and pipes to match) for some model NSR250s... kick arse

[centaurus]

Have you tried Tyga? They make 300cc kits (and pipes to match) for some model NSR250s... kick arse

Don't you need a carb rejet and an oil pump moved to different setting?

[plutoniumman]

So, back to my rebuild.

The other piston looks like it is in great shape. When doing top end rebuilds must both pistons be replaced or can I get by with just new rings for the undamaged piston?

Will this lead to some kind of imbalance having a new piston and an old piston?

cheers

[Sketchy_Racer]

na you would be sweet with out doing anything to the other cylinder.. but for the cost of some new rings.. and maybe even a whole piston kit (dunno how much they are) you may as well give the whole motor a freshen up.

Let us know how you get on with the plating.. as i have a barrel that really needs to be done soon

[imdying]

Don't you need a carb rejet and an oil pump moved to different setting?

That's you mechanics problem (cause if you're asking, then rebuilding it is waaay above your capabilities). You're probably going to need larger jets, but the oil will be fine.