HOW CAN I FIND OUT MY ENGINE CC

[geelymonster]

I HAVE A 2003 GEELY JL50QT-16 AND IT HAULS A$$ IT IS HARD FOR ME TO BELIEVE THAT IT IS 49.5cc I HAVE READ IN ANOTHER POSTING THAT THEY PUT 90cc ATV ENGINES IN THESE ANY HELP SO I CASN DETERMINE WHAT SIZE ENGINE I HAVE WOULD BE GREATLY APPRECIATED. THANKS GEELYMONSTER

[jayhawk]

How fast is it? Define haul a$$... I can hit 48 mph on a flat with my scooter, and it's only a 49cc.

Eric

[90GTVert]

Karl can probably tell you more. The obvious method to know what displacement your scoot is would be measuring bore and stroke. That requires some disassembly though, perhaps there is another way to tell. I know some 90cc 2 strokes were 1PE50QMB or 1E50QMB, but I don't know if Geely had them labeled that way.

[geelymonster]

I can hit 55 on the flats and 60 easy down a slope. and I know if I had a long hill it would probally hit 65. I bought it new about 2 weeks ago with 10miles on it. I weigh about 150lbs

[rallyrrr]

If you don't mind removing (or at least getting it out of the way) your exhaust and spark plug the displacement of a two stroke can be fairly easily measured. Measure from outer surface of exhaust flange with piston down out of the way to the far side of the cylinder. Then bring piston up so that it blocks ex. port. Measure to piston. Subtract second distance from first distance. This is the bore. Then measure diff. between BDC and TDC through spark plug hole. This is the stroke. Use the extended slide of a dial or digital caliper to make the measurements. Be sure to keep slide perpendicular to the surfaces being measured.

Displ. = (Pi * d^2/4 * s)/1000. Where Pi = 3.1416; d = bore (mm); s = stroke (mm); * = "multiply"; ^ = "to the power of"; / = "divide". The 1000 converts cubic mm to cubic cm.

For a 50cc d should be 40 and s should be 39.

Therefore:( 3.1416 * 40^2/4 * 39)/ 1000 or

( 3.1416 * 1600/4 * 39)/1000 or

(3.1416 * 400 * 39)/1000 or

49,008.96/1000 = 49.01 cc

[jayhawk]

If you're sure the speeds you report are in MPH not KPM (many Asian scooters read KPM as the top number and MPH is in fine print), then you've got more than a 49cc engine for sure. The reason I'm asking, though, is because 55 KPM on a flat is about 36 mph which I'd expect for most 49cc scooters.

Why can't you ask the person you bought it from, and if they don't know, I'm sure they know where they bought it from so you could ask the original seller.

Eric

[mi17dy]

Sounds hard, often times the speedometer doesn't have an accurate reading. How come your title doesn't say, and can you contact the manufacturer?

[jakeiv]

I have 3 Geely 50QTs - 2004, two 20s and a 16. They all came in as 60cc which got Geely in trouble with DOT and State registrars who exempt 50cc and under from licensing. All three had speedos labeled as MPH but actually read in KmPH. My top MPH thru a school zone radar was 42 MPH, just before I seized the piston. I now use Valvoline or Amzoil 2 stroke oil in the injector + 1 oz per gallon in the tank. The math formula for displacement is R squared x Pi(3.1416)x stroke. The use of the oversize piston was common for Geely in the US thru 2005 but is no longer available. Replacing the piston and cyl with stock parts will bring you back to 50cc with almost no loss in power. Yes - at least one online dealer would sub a 70cc motor for the Geely 50cc.

[jakeiv]

I have 3 Geely 50QTs - 2004, two 20s and a 16. They all came in as 60cc which got Geely in trouble with DOT and State registrars who exempt 50cc and under from licensing. All three had speedos labeled as MPH but actually read in KmPH. My top MPH thru a school zone radar was 42 MPH, just before I seized the piston. I now use Valvoline or Amzoil 2 stroke oil in the injector + 1 oz per gallon in the tank. The math formula for displacement is R squared x Pi(3.1416)x stroke. The use of the oversize piston was common for Geely in the US thru 2005 but is no longer available. Replacing the piston and cyl with stock parts will bring you back to 50cc with almost no loss in power. Yes - at least one online dealer would sub a 70cc motor for the Geely 50cc.