Andy or Matt please help me,
My girlfriend just bought me a set of barrel and piston for the NSR 150 SP in Singapore.
The barrel is 12001-KW6-840 (cylinder A according to tyga website)
The piston is 13130-KFE-700 (piston C)
According to the FAQs, cylinder A should go with piston B. Will this combination work? Thank you very much in advance.

Anyone???

Sorry I don't know. I think that table may only apply to the 250, so it'll be down to Matt.
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The NSR150 is different to the NSR250.



Use A & A, B & B, and C & C.

I'm not sure of the difference in sizes, as I've never had occasion to need to measure them up, but the A piston on the NSR250 is smaller than a C.
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The NSR150SP "A" cylinder is the biggest, whereas the "C" piston is the smallest.

This comination will give you 0.05~0.06mm piston/bore clearance. The book spec if 0.04~0.05mm, so in the best case scenario you'll be within spec. The service limit is 0.08mm.

Now, we can only order the "B" piston from Honda. There may be other sizes available from old stock at other outlets, but we order direct, sothat's what we get. Honda told us that this piston can be used with any cylinder and not to worry. Apparently they have discontinued the other sizes.

A "B" piston in an "A" cylinder will give a 0.045~0.055mm clearance. Not a disaster.

My only concern here is that if you fit the "C" piston to the "A" cylinder it may be a little noisy.

On my race 28 we used to run an "A" cylinder with "D" piston for fast tracks (0.047~0.053mm) and a "B" piston for short tracks (0.039~0.045mm). The reason was that at fast tracks the engine could be held flat out for longer and the bigger clearance piston allowed for this with less chance of nipping up. The tighter piston on short tracks was at peak rpm for only a short time so wasn't a problem.

Thank you very much. I guess I'll try it and see, if it doesn't work out. I'll order the B piston. Next up is your Expansion Chamber and silencer, but it looks like you're out of the chamber as of today. Any idea when you'll have them available?