ISO Piston

ISO a piston for a small bore TT25 reed valve motor. Cylinder size is 49.05. If you have one or know anyone that does can you please let me know. Thanks. FYI. I will be selling this motor after it is put together if you are interested let me know that as well. Thanks!!!!


Premium User
Someone years ago were re-making these pistons, it might have been Vertex. You might have to put a 50mm in it and go from there. I believe you can bore them out to a 52mm. If you want to get rid of it let me know.
Vertex does make a lot of sizes for many engines, but most are not in the US catalogue, just on the one for Europe, and they won't sell it to you unless you go through the official dealer for one of those countries, which can lead to funnny situations, like the one I had a few summers ago, where the dealer had no clue about what I needed and just told him to please order the reference number I asked without any further questions. Interesting how some things work. It went from the manufacturer in Italy and their dealer to the dealer from Spain, and from there to the dealer for my area. Too many mouths to feed.
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Let me know if you are interested. Thanks


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Looks like 49.96
My caliper is dead


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49.05mm isn’t small bore for a TT25. 48.0mm is stock bore for that engine and they don’t offer anything in the 49mm range for that engine. The largest I’ve ever seen was 48.85mm as a direct replacement. Someone has taken it beyond that and was trying to use a much newer series piston. The pin height you need could be the challenge in finding a new piston. If all else fails I have a Tt25 cylinder within the original piston replacement size range that I will sell. It doesn’t have a piston.