Major mod to an MC-54-150 scooter  By  jeffdeq (Read 2,513 times)

This bike now has 16" wheels. I used an Xingyue ITA YY150T (BMS Pathfinder 150) as a donor bike. The triple tree had identical dimensions in the bearngs and steering stem retainers.

(On a side note, the Roketa MC 54-150 only had 1400 miles on it and had been sitting up for the last 3 years due to engine failure. On the triple tree for the 13" wheel the bottom bearing was packed in grease but the top bearing had no grease. However the top bearing was still useable.)

After installing the 16" triple tree I had to grind back the steering stops about a half inch to allow for more radius in turning. This was a simple bolt in. All work was done with the body off the frame. the speedometer cable was the right length and fit the instrument cluster. The speedometer is reading 50 mph at actual 45 mph.

The engine was a little more difficult to install. A 16" wheel bike has a wider engine case than the standard GY6 engine. It took a 9 1/2" grade 8 bolt to hang the engine to the frame. The carb is a tight fit to remove unless you pull the shocks to allow the frame to lower thus rotating the engine hanger away from the carb.

After I ran the brake lines to the rear I finished servicing the motor, replaced the belt and rollers (using 14 gram) and secured the wiring harness. I then carefully put the body back making all connections secure. When I disassembled the bike I found that there were a lot of missing bolts and screws along with loose bolts. This bike appears to never have been serviced leading to the engine failure.

As for the 16" wheel donor bike, it was a parts bike with many body parts missing. However the engine was still functional so there was no costs for rebuilding it.

All in all, the bike runs good. I have to replace the carb because it has issues for idling properly. The 16" wheels give the bike a smoother ride and the wheel base is 10" longer. The ride is very stable. I really enjoyed test driving it this afternoon. Top speed is 59 mph according to my gps.

I now have to extend the center stand because I don't think I want to pack around shim blocks, LOL! I also had to re-mark the dipstick for the crank case fot a proper oil level. The geometry of hanging this engine in this frame has the engine at a higher slant.

I have 2 other 16" bikes, a Lance Phoenix 150 and a BMS Pathfinder 200. The Lance has the best ride and engine performance. The BMS is the strongest and fastest at 63 mph but has a horrible, cheap feeling ride.

Awesome ride!!! Looks great and gotta love it when you can take 2 bikes in shambles and make one fantastic one!

With the exception of the carb, this bike runs and handles well. The 16" wheels make for a very stable and comfortable ride.

The first carb I tried was put together from various carb parts. It would not idle properly and top speed was 50 mph. I bought a new carb for $45. The $29 carbs on ebay provide dissapointing performance. The $45 carb came in and after I installed it. It developed a surging idle. I could do nothing to level it out but top speed was smoother at 55 mph.

I have 3 other 150cc scoots and I have a Deni carb on each of them. The Deni performs flawlessly and the low idle jet mixture screw will adjust out properly on them. So I ordered another one for this bike...$60. It came in in 4 days. Installed it and the bike now idles perfectly, has smoother and quicker acceleration, and now has a top speed of 62 MPH. It also does well hauling myself and my wife and it will still do 55 MPH.

I am very pleased with this Xingyue 150cc engine. It has 2300 miles on it and runs very strong. This Roketa MC-54-150 scoot body is fairly heavy compared to my other scoots but it cruises very well.

Today is my birthday. My wife gave me a party this afternoon and one of my buddies is a die-hard Harley motorcyclist. I got him to test drive my chinese scoots. He said that they were a hoot to ride.

I will admit that the chinese scoots are not the same quality as a Piaggio but if you can do your own troubleshooting and repairs these scoots are fairly simple to repair. The parts are becoming less and less expensive.