Hi Everyone, I have a Superbyke RMR 125, which is a variant of the Qingqi QM125. I have made a number of upgrades to it which have much improved it, so I though I would share......
Firstly, I should point out that my bike started life as a QM200, but I managed to kill the engine through my own stupidity - it only had 300Km when I got it but I rode it at sustained high revs/max speed, and also I had put high performance semi-synthetic oil in (I found out too late that being an old engine design, it actually runs best on low-tech 10w40 mineral oil).The whole point of the bike purchase was to run as a economical commuter, as I have a Honda VFR800 for speed thrills and touring. The VFR was costing me way too much in petrol/tyres/servicing, so by sharing the workload with the Qimqi I wanted to reduce these costs. But this also meant that once I broke it, I couldn't justify spending a lot on new parts and labour for an engine rebuild. I lucked upon a used Sinnis Apache 125 ( also a Qingqi QM125)engine on ebay, which I haggled down from £175 to £100. Being basically the same bike chassis wise, it bolted straight in with no dramas ( in the unlikely event that anyone else wants to do the same!).
The engine came with the 125cc carb, but no airbox, so I bought a Pod filter from Xian racing, which together with a Xian Racing P&P exhaust I already had on the bike should have been a good setup. However, after a number of test runs and endless fiddling, I could not get the fuelling right. The bike was guttless off the line, had some brief areas of peaky power bewteen 3 and 5K and woudl only spluuter its way to a max of 55mph, with little power to get past anything going faster than 40mph. Whilst this still fullfilled the cheap transport mandate, it was not ideal, and borderline dangerous due to the need to maintain forward momentum.i.e I was taking risks to keep moving!
So.....my mind wandered to the Mikuni 28mm CV carb and airbox from the original 200cc engine. The only obstacle was the manifold adapter (goes between the carb and engine head). The 125 item was much smaller, both in bore and distance between the mounting bolts.
Then came some very dodgy 'custom engineering...I managed to sleeve down the 28mm carb adapter using a chopped down conical bottle top ( which was snug push fit), some 22mm brass tubing and some araldite.I then widened the mounting holes so I could bolt it to the cylinder head.
Anyway, I mounted the adapter, CV carb and airbox, started her up and waited for disaster....mircaulously, there wasn't one! She fired uo fine, and after some minor adjustments to the idle speed and air/fuel mix, everything ran perfectly. The bike now has a lot more pep from pulling away, and briskly makes it way to 60mph, with 70mph possible in the right conditions. More importantly, there is now a lot more oomph in the 20-50mph range, which means I can easily stay ahead of 4 wheeled traffic on my 20 mile backroad commute.I haven't dyno'd the bike, and don't intend to, but I reckon it has added 4-5 bhp to the standard 9.6bhp output of the 125, and a dollup of torque.It really doesn't feel any slower to 60mph than the 200 did, if any thing,it feels better!
So to anyone with a 125 considering a Molkt carb or similar, see if you can get hold of the Mikuni CV 28mm carb and airbox for the 200, it may be a better bet.

I would also reccomend the following cosmetic upgrades for both models:

- Renthal MX bars to replace the heavy and too narrow originals
-Thicker grips
-Mirror extenders

I did the above for under £50 and it has made a big improvement in how the bike feels to ride.