I'm new to 2-strokes and although I've ridden a MC21 briefly, I don't know too much about NSRs. However there is a MC18 in my area that I'm interested in picking up. What should I look out for?

I've owned several bikes, so I know what to look for in terms of fork seals, suspension, tires, chain/sprocket etc.

Obviously I won't be listening for valve chatter, but what specifically should I look for?

What are the best tells that pistons/rings and/or crankshaft are soon due for replacement?

Thanks

Curifor

Only way to tell really is to take along a compression tester.

See if the seller has paperwork to prove recent rebuild.

Check head nuts for rust - if they're bad the head hasn't been off in a long time.

Check the powervalve works by rotating the motor when the ignition is off. It should be stiff but move - if it doesn't it's well gummed up and I'd walk away, as this can burn out the motor and blow the CDI. Not cheap.

Pull a spark plug and check the colour - white is lean and about to / already has detonated.

The bike should start in 3 or 4 kicks. If it doesn't it may be a bad mixture, but it may be crap compression.

Ask what mods have been done - the 18 was unrestricted until the very last few.

I purchased my MC21 in Nov last year.The seller told me it had had a recent top end rebuild.He had no paperwork to prove this though.I took his word,(I wanted the bike),and he was proved a liar.
The crankcase oil seal failed and the engine needed stripped.I used a local dealer who I have known personally for many years.When the engine was stripped down it was then obvious that the heads hadn't been removed for some time and the pistons were approaching their last legs.I got this done then and there,the old parts shown to me and a receipt given.
The lesson is-DON'T TRUST A SELLER! Ask for proof.If he cant give it to you,why not?I am new to 2 strokes too-I am learning slowly but surely.
Craig