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Discussion Starter #1 (Edited)
Has anyone tried this piston kit? This one is advertised as Vito's. I couldn't get the link to copy on Ebay.

YAMAHA BLASTER SUPERSTOCK PISTON KIT 67MM BORE SIZE ADDS 5 + HORSEPOWER

Some of these pistons look like they are for 2 strokes while some look like they are for 4 strokes. I don't know about TW200 compatibility.
 

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Ok, I saw this is not compatible.

Now for the crazy. I was reading about the Mazda Skyactiv-G which the 71mm piston has a compression ration of 13:1. Do we have any brave souls who would dare to experiment and see if they could match it up to a TW rod? They also have a 14:1 cr but is a much bigger bore.
 

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We're talking apples to broccoli here.

2 stroke and 4 stroke pistons are not interchangeable. I mean the bore might match up and technically fit, but they are designed for completely different lubrication. 2 stroke pistons are not meant to control oil and are designed to allow oil (from gas) to lubricate the piston walls and rings, where 4 stroke pistons have oil control rings that "scrape" the cylinder clean so oil is not allowed into the combustion chamber. 2 strokes only have compression rings. You can probably see how mis-matching this would not work, at least not for very long.

Plus, other factors go into determining effective CR, not just the piston. You could deck down the TW's head, leave the piston stock, and effectively increase the compression ratio since you decreased the head area. The piston's travel has the same displacement but it's now being shoved into a smaller area, so the ratio between BDC and TDC has changed. The Mazda could have an extremely tiny head volume and a dished piston, which when put in the TW would actually lower it's CR despite the engine it was poached from has a higher one. You'd also have to consider valve lift and piston clearance based on how tall the piston is. Point being a lot more factors go into it than just grabbing a piston with the same bore, from an engine that had more compression.
 

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For offroad stuff I'm always going at half throttle so extra go has little value to me. On the road it might be different.

Sent from my LML211BL using Tapatalk
 
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