Only 23 Cruise MPH On GPS?

GoldenMotor.com

Bikeman

New Member
Apr 26, 2011
27
0
0
MS Gulf Coast
I just fixed everything back up with my crankcase leak and still doesn't go fast enough for me. This is my first bike kit and I just want to cruise at 25-30 with my 250pound self on it. Is this possible with just going with a 36tooth and pedaling it a little to get it up and go? I have 7 speed so that is no problem. I just want lower RPMs and a little higher cruise speed. Mine is a 41 tooth 66/80 CC I believe. I can wind it out to about 25, but it sounds like it's going to fast after that and I ease off a little on the throttle and cruise at 23MPH without it sounding too bad. 19 or so it sounds like it's starts getting a little blubbery. It will ease along as as slow as 10 and not stall the engine. Is that about all to be expected with this drivetrain and my heavy self or can I get more?
usflg
 

2door

Moderator
Staff member
Sep 15, 2008
16,302
175
63
Littleton, Colorado
Is this a new engine? The Chinese 2 strokes are known for producing more power as they age (accrue miles). The older they are the better they seem to run. If your engine has less than 100 miles on it don't despair. It will get better the more you ride. The piston rings will seat better increasing compression and that alone will increase power output. I was not sure from your post if you're running a 36 or a 41T sprocket. The 41 is a good all round gear ratio for most rider weights and terrain. The higher gear, 36T will decrease your top end rpm but might require some pedal help on steeper hills and from a dead start.
Keep riding, build up some miles/hours and see if your little China Girl doesn't start pleasing you more the older she gets. (read my signature :)
Tom
 

Bikeman

New Member
Apr 26, 2011
27
0
0
MS Gulf Coast
Well I got a couple hundred miles so far on it. I did break her in a little hard though. I didn't read the instructions and broke it in like I would a boat motor. 32:1 for the first tank and then 40:1 after that. Did plenty of accel/decels to seat the rings though and no WOT's until the second tank. I'm just scared how much noise they make, sound like they are going so fast that something is going to fly out of it any second so I never wound it out to see how fast it would go. I live in flat terrain and will mostly be cruising. I believe my current gear is a 41T, I want to go to the 36T I think, if it won't be too bad on takeoff.
 

biknut

Well-Known Member
Sep 28, 2010
6,631
409
83
Dallas
I agree with Tom. My motor started running better after about 500 miles.

Have you done any tuning? My bike ran very rich out of the box. I leaned the jet to a 68, and changed the needle clip to the top position.
 

Bikeman

New Member
Apr 26, 2011
27
0
0
MS Gulf Coast
Nope, just like it came out of the box. Only thing I did was seal the carb to intake and top of carb where throttle cable goes. I admit I am scared to open it up because the thought of the engine locking up at high speed doesn't sound like it would be good for me! LOL! i mean how fast are you guys running these things?
 

2door

Moderator
Staff member
Sep 15, 2008
16,302
175
63
Littleton, Colorado
It's about time you started looking at your spark plug color. As I'm sure you've probably read here, you're looking for a chocolate brown color of the center porcelain. Darker than that, black and/or wet, indicates a rich condition. Raising the 'C' clip on the needle might help. If the plug is lighter, more light tan to white, lower the 'C' clip.
Make sure your choke plate is open completely and not vibrating closed.
Check the air filter element and clean it if necessary.
Let us know how you're doing.

As for your question, "How fast?".......this question will surely open a can of worms. Suffice it to say that you'll get lots of answers; everything from 20 to 50+mph. So hang on.
Tom
 

Bikeman

New Member
Apr 26, 2011
27
0
0
MS Gulf Coast
Been checking the plug fairly regular. Replaced the L4 China plug with a NGK BH6 and it really seems to be a good plug. The plugs are coming out dark brown like to be expected. If I go richer than 32:1 the plug will get a little black with maybe a little bit of oil on the plug when it was 24:1. I replaced the cheap plastic spark plug cap with a real spark plug cap of a lawnmower so it grips the plug better than the piece of crap that came on it. I just cleaned the air filter screen yesterday. Seems to be running Ok from what I'm learning. Just a combo of my weight and size and it being a heavy beach cruiser Schwinn bicycle I guess slowing me down. I'm not too disappointed in 23MPH. That's faster than I can pedal anyway! LOL!
 

virginian

New Member
Dec 19, 2009
117
0
0
McLean VA
Are you saying that your average trip speed was 23 mph measured by a gps tracker or are you saying that 23 mph is your full throttle speed using a speedometer?
 

DuctTapedGoat

Active Member
Dec 20, 2010
1,179
10
38
38
Nampa Idaho
23 MPH is the speed (measured with a GPS) that sounds the best. He can go 25 but doesn't like the RPMs, and when he goes 19 it sounds "blubbery" (four stroking?).
 

biknut

Well-Known Member
Sep 28, 2010
6,631
409
83
Dallas
IMO 25 mph with a stock 44 T and a 26" rear wheel, is reved pretty tight. Especially with a low mileage motor. It took my motor a long time before it wanted to rev past about 5800 rpm.

My bike has a 40 T rear sprocket. It's reving about 7000 @ 33. That's about 1000 rpm past where the motor is smoothest. It goes 28 @ 6000. 25 on my bike feels great. It's in the power band, and still feels pretty smooth.

That's why I'm a member, and supporter of the 20 MPH club.

This is what my gearing works out to with a 40 T

RPM
1000 4.7
1200 5.7
1400 6.6
1600 7.6
1800 8.5
2000 9.4
2200 10.4
2400 11.3
2600 12.3
2800 13.2
3000 14.2
3200 15.1
3400 16.1
3600 17.0
3800 17.9
4000 18.9
4200 19.8
4400 20.8
4600 21.7
4800 22.7
5000 23.6
5200 24.6
5400 25.5
5600 26.5
5800 27.4
6000 28.3
6200 29.3
6400 30.2
6600 31.2
6800 32.1
7000 33.1