Baotian BT49QT-28C 47MM BEAST!

[bazhee]

Hi guys, this is my new thread. I have opened not many threads on the forum but this is my official one for my scoot. 
I asked about help many times from you and used all advices and tips from the forum. 4 months ago I did not knew a thing about scoots, 2 strokes or anything like that. I dont know a lot now too but  I am lot better then I was before..Thanks to all users or the support. This is my scoot: 

I was installing parts at the service, maintaining and all that kinds of stuff. I had thrown lots of cash ( around 500$+) for it and now I am working on my own on my scoot. btw the machine is the yamaha jog china clone (1e40qmb) 
Okay so my current setup is:

Cyl. Kit: 47MM China BBK (I guess it's Hoca) 
Exhaust: Gianelli Extra Carbon
CVT:
Polini Speed Control Variator
Polini Air Speed Variator Pulley
Polini Kevlar Belt
Polini Racing Clutch
Polini Torque Driver
Polini Clutch Bell 

Current MAX SPEED: 130 kmh - 82mph



The scoot is madness, it pulls really hard and has strong acceleration till max speed.. However it tears apart on every ride because it's too much power for a chinese steel that is not even good for a "bicycle".
Future Plans: Going back to 50cc stock cylinder kit and stock clutch, torque driver and bell.. Updates soon!  

[humanshield]

You'd run just about even with a 250cc Kawi Ninja in that case.  They can hit about 87 depending on the winds.

Tuck a little tighter and you just might break 100mph. You are SO close

[bazhee]

Jul 20, 2016 12:50:43 GMT -5 humanshield said:

You'd run just about even with a 250cc Kawi Ninja in that case.  They can hit about 87 depending on the winds.

Tuck a little tighter and you just might break 100mph. You are SO close

I could probably get a 3-4 miles with heavier rollers and a little bit more tune. However running the stock chines crankshaft at 14.000 rpm is just not a great idea... I am going back to stock cyl soon.. 

[spaz12]

Really cool looking scooter.

I think though that you're speedometer is lying (badly) to you. Check it with GPS.
The Gianelli Extra is also a sub-10k pipe which tells me that your tach isn't telling the truth either.

[Lucass2T]

That speedo is soo far off...
I think you're lucky if it's 60mph @ gps...

[gsx600racer]

The Polini parts list is good, but I don't think they make it 82mph good. Unless that scoot is stroked, cylinder has some crazy porting done, engine turning 12-14k rpms, and has some gearing, I think your speedo is fibbing a tad

[niz76]

My stock speedo on Roketa Air says I'm doing 80mph when in reality it's 60mph GPS. That's how far they can be off!

[bazhee]

Some update guys, scoot blew up today I broke the crank.. Blown the piston also and the cylinder has lots of lines on it hahah. I forgot to mention up in the post that I was running a 19mm DELLORTO carb. I am going back to all stock parts now except for the variator and the exhaust. So I am thinking about reworking the old cylinder (from 40mm to 40.5MM and installing a japanese good quality piston). I had some jetting problems before with the old carb but now I will not run a BBK so I guess it will be fine? I will use a 75 or 80 main jet and will see how the bike will perform. I will also install a new China crank again because I am not looking for much power now.. I will try to install the kit on my own and I will adjust the CVT so my bike delivers max power below 7500 RPM for the first 1500 miles. I think this would be the best way for breaking the new kit. After that I will adjust the CVT to rev higher and pull stronger. I am looking at a max speed of 55MPH while standing at around 8500-9000 RPM MAX.

BTW UP IN THE POST: The Speed with white numbers is from iPhone APP - Snapchat which does count through GPS
About the cylinder kit, I was running a kit with 47mm bore, the cylinder has been heavily ported (not by me), and also the cyl. head has been aligned -2mm I think.(Not sure about these bc I havent made those tunings). The scoot had huge compression, the kickstarter was nearly as hard as on a 4stroke dirtbike.. When I installed the clutch it revved almost 8500 RPM before engaging and when accelerarting in full power the rpm needle went 1,5 inch after 12k rpm so I thought it's about 14k. For the speed I have tried gps and also running straight to a car, it showed up with 80MPH everytime.
I am really sorry now that I learned much about scoots and realised that air cooling ones are very bad for tuning because they OVERHEAT in almost 5 minutes and their performances are at very lower rpm than LC scoots. I also learned that doing so much tuning to a chinese cyl and piston will give you lots of power and you will be happy for just one week because it's quality is crap. Thank you for following this post, I will be back after I rebuild my scooter soon.

[aeroxbud]

Good luck with the rebuild. If you go with something like a Polini or Mallossi cast iron cylinder it makes really good torque. Is low revving, and should be OK with the standard crank