The TYGA 300 pistons have a cut skirt. Now I know the crankcase can be attacked with a dremel and full skirts can be run.

What about cutting both skirts to even the mass distribution up and balance things better? Anybody recommend this? Would shead some weight in the process, however that is not my motivation for asking.
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MC21 Honda NSR250. TYGA 300 conversion.

I wouldn't reduce the length of the skirt just to even it up. Reducing the skirt on one side is bad practice in my eyes but I see why they had to do it.

The part of the skirt you are reducing is also the most important part being where the piston is at its largest. I have personally had one skirt fail on a 300 kit and I know of another where two failed.

If you want to stick with a 300 I would modify the crank cases to allow for a full proper skirt.
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If I have to take the carbs off once more...

Did the failed pistons have a cut skirt? I am considering going to full skirts if it's worth it as it is rebuild time.

The only skirts that failed were trimmed yes.
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If I have to take the carbs off once more...

I think the cast pistons have a bad history , perhaps the machining process causes fractures in the piston leading to a possible failure - along the lines of a dropped piston is a damaged piston ?

Yeah, perhaps, but cast pistons are machined after being cast...

Still hesitant to go the Wiseco route. I think cast are better for most two strokes.

We had more problems with the Wiseco pistons than the cast ones.
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If I have to take the carbs off once more...

Interesting... Did you find out why?

What did you end doing to sort it out?

We went back to a 250, made more power and stopped seizing.

I personally went through around 14 pistons and 10 barrels. When we got the power we wanted we suffered with detonation and lack of revs. If we got the revs we didn't make the power.

We used both cut skirts and standard ones. We never had any trouble with exhaust bridges though. The wiseco's seemed to stand up better to the detonation but seized quicker if you didn't prepare the pistons.
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If I have to take the carbs off once more...

More power? Hmm... Why wouldn't an extra 50 cc make more?

Anyway, let me know if you've got a left over cylinder floating around...

It is debatable about that ! I think that we have made good improvements with some good R and D . if we all put our info together it will speed up the 300 development. My research has shown the potential of a 300 over a 250.

Yes Neal, your 300 did make me smile!

Is there a way to get NSR150 pistons to fit? Different pin, so something would need to be changed. Are they better pistons? Would it be worth it if it were doable?
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MC21 Honda NSR250. TYGA 300 conversion.

The nsr 150 piston uses a 16mm gudgeon pin , could possible make it work but the piston has a different measurement from the pin to the crown so your barrels will be too short .

Ahh okay, I knew there'd be more to it and guessed that would be the case.
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MC21 Honda NSR250. TYGA 300 conversion.