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Just bought a new piston port 175 alloy cylinder with aluminium barrel on ebay for a buy it now price of £35.
Anyone know who makes these ? Sorry to be a bit vague.

Is it aluminium fins cast around a steel inner? Try with a magnet.

If so, it is most likely one of the barrels made for scooter restorations, commonly known as an SR175.

very tuneable

Knowledge wrote:Is it aluminium fins cast around a steel inner? Try with a magnet.

If so, it is most likely one of the barrels made for scooter restorations, commonly known as an SR175.

very tuneable

I think so,but have not got it yet so I cannot check it.

Knowledge wrote:Is it aluminium fins cast around a steel inner? Try with a magnet.

If so, it is most likely one of the barrels made for scooter restorations, commonly known as an SR175.

very tuneable

Aren’t there a lot of very poor quality Indian versions knocking around that need, at the very least, lots of tuning work to get them useable?

I bought one of the 185 alloy kits from a dealer some years ago , could never get it running properly so took it to Rayspeed for a good dose of looking at , Scott diagnosed it as having an oval bore and misaligned transfer ports , ended up boring to 198cc and having the ports fettled , ended up costing me a fortune so worth checking yours before you go any further

If it's the one i saw, with misaligned inlet and outlet studs, I seem to recall seeing that the exhaust port had the same problem as the 175 and 185 that I've had.

There is a notch in the bottom centre of the exhaust port. You can just accept this or use a 60 stroke crank, base packers no head gasket to get the piston crown flush with the bottom of the port. Obviously this will raise your exhaust and transfer timings, but maybe that suits you.

Also, the transfers are a shambles where they enter the barrel. I don't have the tooling or skills to sort this properly so will ask a grown up when I get round to it.

The inlet is a bit of a mess too, but that's easy to sort.

I've also heard that they wear out quickly but I've never actually run one so I can't comment.

Other than that, they're absolutely fine.

drivera wrote:I bought one of the 185 alloy kits from a dealer some years ago , could never get it running properly so took it to Rayspeed for a good dose of looking at , Scott diagnosed it as having an oval bore and misaligned transfer ports , ended up boring to 198cc and having the ports fettled , ended up costing me a fortune so worth checking yours before you go any further

Oh I forgot , one of the inlet studs pulled out and had to be helicoiled back in

I got one years ago from SR, before the Injuns started making them "back street", so it was the "real McKoy" but even that is a pile of cr*p as the liner isn't in line.

I’ve also got the Sr but the 190cc using Suzuki ts piston with all the ports matched n tuned. Never got round to fitting it so it’s an shelf ornament for the time being

dickie wrote:If it's the one i saw, with misaligned inlet and outlet studs, I seem to recall seeing that the exhaust port had the same problem as the 175 and 185 that I've had.

There is a notch in the bottom centre of the exhaust port. You can just accept this or use a 60 stroke crank, base packers no head gasket to get the piston crown flush with the bottom of the port. Obviously this will raise your exhaust and transfer timings, but maybe that suits you.

Also, the transfers are a shambles where they enter the barrel. I don't have the tooling or skills to sort this properly so will ask a grown up when I get round to it.

The inlet is a bit of a mess too, but that's easy to sort.

I've also heard that they wear out quickly but I've never actually run one so I can't comment.

Other than that, they're absolutely fine.

Yep,that's what I have got,given it to Russ at Lincs Lambretta to sort out for me.