BT80 tuning


Well-Known Member
Jul 9, 2016
I'm just curious: has anyone done port work, tuned expansion chamber, aftermarket carb, crank balancing or aftermarket centrifugal clutch mods to this engine yet? I'm curious to this engine's longevity, stock and at higher hp; then potential hp that can be achieved. The head and cylinder are 1 piece, but I'm sure that there is another 2 stroke cylinder that is close enough with port timing, piston pin location, stroke and bolt spacing that maybe a larger cylinder can be used as a "big bore" kit with a little modification. It seems these engines didn't really make it as a big hit, aftermarket parts are almost non existent. Hell, I haven't seen a single vid running anything but full stock. This engine seems to have potential, but it seems folks aren't really willing to dive into the unknown, especially when our current well known bicycle 2 stroke isn't really that reliable and it may be too expensive on an unknown that may be an expensive paperweight in no time flat. I would hit the new frontier but alas, lack funds for unknowns. It would be nice to not have to pedal or pull start. The onboard electrics would make headlight, turn signals, tail and brake light much easier to deal with since it charges as you ride. I just wish someone has tried at least an expansion chamber on it, it might be better than most current kit 2 strokes in nearly every aspect...except weight.


Active Member
Oct 30, 2018
Hell_On_Wheels has an engine, not a BT80, that came with the one piece head/cylinder.
He was having some issues trying to get a CDH reed cylinder and head to fit it after "blowing it up." I don't think the original top end lasted for him at all.
Maybe the crankcase is different. IDK.
That is one of the threads discussing his engine.
The other is

Anyway, it's the only non-bt80 setup I've read about with the one-piece cylinder/head.

You might look through his experience and port timing descriptions to think about what other cylinders other than CG might be a close fit.


Well-Known Member
Jul 29, 2018
i look at the pics, and thought wow it has a big exhaust port,, oh and saw replacement jugs are available.
I like the idea it's electric start, but any porting would be really hard so for 2x the cost of a basic HT, you'll have a heavier bike, not as quick as a mild upgraded HT
it's good for ppl just want convenience and will just leave stock


Well-Known Member
Apr 9, 2018
I wonder why they don't make a 49cc version of the BT80 maybe called the BT50 but not sure. Since it has a full electric system it would be easier to register a bike with the engine equipped as a moped. I have noticed it seems they are slowly phasing out the 48cc engines with the 66cc/69cc engines. Possibly because no one buys them. I would like to have one of the Russian motors that Ht's are based off of I bet they're better made.