GT 125 upgrade

Hi Guys, first time post. Im looking to get some more oomph from my 67 GT 125 and was hoping for some pointers for getting the best from my scoot with regards to 177 kits, carb and exhaust, bearing in mind its a 2 port.

Have a look on for a px or t5 engine. I assume ur running 6 volt electrics so you’ll need a regulator and new bulbs and some reworking of your loom. This may all sound a bit much but it will work out cheaper than tuning kit and prove more useable for commuting

Interesting point that about getting your original bits back. Seems to be an unwritten rule in some shops that they keep hold of the original part if they are upgrading something on someones scoot.

The fiddliest part of this conversion is the wiring harness alteration or fitment of a new harness.

Ive put a px harness in my smallframe and that was one awkward twat to feed thru.

Mike A565

Hi Brader,

I put a PX125 with 150 top end into my 67 Sprint and its made a world of difference. I got scooterworks to do the 12V conversion and they were fine about it, very reliable as well. Did a round trip from London to Manchester a few weeks ago and was able to cruise comfortably between 55-60, and even got close to 70 out of it.

Otherwise I’ve heard of a DR180 kit working with 2 port engines, or if you just wanted to keep it simple you could put a 150 top end on your current engine for a little extra.

There’s a place near King’s Cross station called 2 wheels, they are pretty helpful, have you heard of them?


depends how much of a purist you are, but theres always cheap px engines goin on scootertrader website and one of them will be cheaper kits,carb exhaust and associated ancilliaries [:drink:]

I think ill try to get a p200 from somewhere as that seems the best option.
as for Scooterworks, i have found them pretty unhelpful in the past, but didn’t know about their thievery !

I used the original 6v loom and a light switch thats adapted for the 12v, dunno how it works but it’s essential.

When mine was taken in I was told that the brand new rear brake switch I had couldn’t be used so they (Scooterworks) used a 2nd hand one which was a state, charged me £8 for it and when it eventually bust(as it was cracked) I tried a new switch, same as the original one I had, and guess what it was fine. And they kept the original new switch telling me it was useless, plus a few other minor bits.
My point is they kept some parts they hadn’t replaced but also replaced new parts with shitty used bits. Use them, but keep yer eyes peeled.

Fuck me, got into a rant there…

cheers KK , i have managed to get my hands on a px200 engine so im going to stick that in next week sometime

wouldnt call myself a purist, just need a bit more mid range for driving to work through london every day, sometimes find myself between two double deckers and need that burst of speed !

If you get a T5 or P Range motor and need the 12v conversion doing Scooterworks will do it (in London)for about £100, just make sure they don’t „forget“ to put some bits back on and make sure they don’t do „extra“ work you didn’t ask for. Robbing bastards.

It’s not too difficult to do yourself.