Topping out at 40 MPH, 6hp, TAV, 10:72, 20" wheel

GoldenMotor.com
professor

professor

New Member
Oct 14, 2009
500
1
0
Buffalo ny area
Find a hill!
Just fooling.
Change the gear ratio, your motor is probably screaming.

But my question is "Do you really want to go that fast?"
Observe the pavement flying underneath you, then imagine some malfunction causing you to depart the bike at that speed, and contemplate what it would feel like sliding down the road.
Maybe my age is showing- had enough pain for one life.
 
wayne z

wayne z

Active Member
Dec 5, 2010
1,743
5
38
louisiana
Do you still have the govenor disconnected? If not, that's holding back the rpm's. 50 is way too fast for safety with standard bike tires and wheels. At least wear a helmet safety gear.
 
S

socal_machinist

New Member
Jun 23, 2012
37
0
0
Los Angeles, CA
Venice Motor Bikes said:
40 MPH is a very respectable speed for a motorized bicycle!
You should upgrade the brakes NOW!
Click to expand...
Oh I'm running motorcycle brakes right now, front and rear disks WITH brake lights. Stopping from 40 MPH is NO issue
http://www.youtube.com/watch?v=nX8Cs5FDTnE

I just need another 10 MPH, how the fudge are people doing 50 MPH w/a 2hp 2 cycle engine? is everyone getting "creative" with numbers or something?

EDIT I am running a 12:72 ratio

I've got two sprockets in the mail one 16 and one 18

40x (16/12)=53.34MPH
40X (18/12)=60MPH

I REALLY doubt that math is a direct correlation to actual speed if I had to guess the 16 is going to put me at 45 and the 18 is going to put me at 50.

Just an FYI sprockets for $3-4 each !!!!!!!
https://www.surpluscenter.com/ bookmark that guys!!
 
Last edited:
wayne z

wayne z

Active Member
Dec 5, 2010
1,743
5
38
louisiana
socal_machinist said:
Oh I'm running motorcycle brakes right now, front and rear disks WITH brake lights. Stopping from 40 MPH is NO issue
http://www.youtube.com/watch?v=nX8Cs5FDTnE

I just need another 10 MPH, how the fudge are people doing 50 MPH w/a 2hp 2 cycle engine? is everyone getting "creative" with numbers or something?

EDIT I am running a 12:72 ratio

I've got two sprockets in the mail one 16 and one 18

40x (16/12)=53.34MPH
40X (18/12)=60MPH

I REALLY doubt that math is a direct correlation to actual speed if I had to guess the 16 is going to put me at 45 and the 18 is going to put me at 50.

Just an FYI sprockets for $3-4 each !!!!!!!
https://www.surpluscenter.com/ bookmark that guys!!
Click to expand...
LOL no way do I believe the chinagirls will do 50 mph.

I have a 99cc Preddy on my 2 speed tranny build. I have a 10.75:1 final drive ratio, and I can get 46 mph out of it.
579326_475107762505328_100000183244892_2036434_1363544906_n.jpg
Yo need to get your drive ratio to around 10:1 to get to 50 mph without over revving your engine.
 
locell

locell

Member
Jan 16, 2010
215
0
16
mesa
Run the engine as lean as possible (less oil in the gas), get a 36 took sprocket on the rear, don't run a chain tensioner on the drive side, put it on the pedal side. make sure everything is well lubed and moves smooth, I got my cranbrook to 59 mph with this in mind.
 
The_Aleman

The_Aleman

Active Member
Jul 31, 2008
2,653
4
38
el People's Republik de Kalifornistan
locell said:
Run the engine as lean as possible (less oil in the gas), get a 36 took sprocket on the rear, don't run a chain tensioner on the drive side, put it on the pedal side. make sure everything is well lubed and moves smooth, I got my cranbrook to 59 mph with this in mind.
Click to expand...
Doubt it. Not that your post has anything to do with this thread, but I truly doubt you spun your engine to 11,200RPM on your Cranbrook.

That's with a 26" wheel. If your Cranbrook has a 24" wheel that's about 12,000. Sorry, not going to believe that. rotfl
 
locell

locell

Member
Jan 16, 2010
215
0
16
mesa
The_Aleman said:
Doubt it. Not that your post has anything to do with this thread, but I truly doubt you spun your engine to 11,200RPM on your Cranbrook.

That's with a 26" wheel. If your Cranbrook has a 24" wheel that's about 12,000. Sorry, not going to believe that. rotfl
Click to expand...
I don't have a tach, just a gps, so i'm not really sure what my RPMs run. You didn't even ask if I was going downhill.....
 
Ibedayank

Ibedayank

New Member
Oct 29, 2011
1,171
0
0
Columbia Tennessee
locell said:
Run the engine as lean as possible (less oil in the gas), get a 36 took sprocket on the rear, don't run a chain tensioner on the drive side, put it on the pedal side. make sure everything is well lubed and moves smooth, I got my cranbrook to 59 mph with this in mind.
Click to expand...


this bike has gone 55+ a few times

31cc friction drive 7/8s roller and 26 inch tires
so anything is possible



when its tied down on a trailer or in the back of the truck
 
The_Aleman

The_Aleman

Active Member
Jul 31, 2008
2,653
4
38
el People's Republik de Kalifornistan
locell said:
I don't have a tach, just a gps, so i'm not really sure what my RPMs run. You didn't even ask if I was going downhill.....
Click to expand...
Wouldn't change the fact I don't believe you. The math is easy to calculate, your ratio as you claim is ~14.76:1
I've seen HTs destroy the upper conrod bearing at 7K RPM, no way am I going to believe 11+K.

When Baird hit 54, his professionally tweaked engine wasn't even doing 9K, he had a 27 or 28T sprocket.

You'll be hard-pressed to find anyone who will believe your speed claim. Anyway, that's all I've got to say on the matter. This aint the thread for it.
 
locell

locell

Member
Jan 16, 2010
215
0
16
mesa
The_Aleman said:
Wouldn't change the fact I don't believe you. The math is easy to calculate, your ratio as you claim is ~14.76:1
I've seen HTs destroy the upper conrod bearing at 7K RPM, no way am I going to believe 11+K.

When Baird hit 54, his professionally tweaked engine wasn't even doing 9K, he had a 27 or 28T sprocket.

You'll be hard-pressed to find anyone who will believe your speed claim. Anyway, that's all I've got to say on the matter. This aint the thread for it.
Click to expand...
cool story bro. .wee.
 
S

socal_machinist

New Member
Jun 23, 2012
37
0
0
Los Angeles, CA
Ibedayank said:
http://motorbicycling.com/attachment.php?attachmentid=49256&d=1340506966[/IMG]

this bike has gone 55+ a few times

31cc friction drive 7/8s roller and 26 inch tires
so anything is possible



when its tied down on a trailer or in the back of the truck
Click to expand...
I was about to post spiderman questioning till I saw the last line lol.




Well I put on that 16T gear and got like another 4-5 MPH so big whoop I might try another speed run later tonight

http://www.youtube.com/watch?v=GLk-JMOo2-8
 
wayne z

wayne z

Active Member
Dec 5, 2010
1,743
5
38
louisiana
locell said:
Run the engine as lean as possible (less oil in the gas), get a 36 took sprocket on the rear, don't run a chain tensioner on the drive side, put it on the pedal side. make sure everything is well lubed and moves smooth, I got my cranbrook to 59 mph with this in mind.
Click to expand...
Running an engine lean normaly means less fuel not oil. The oil mix is referred to as ratio, not rich/lean .
The amount of oil on the fuel does have a very small effect on fuel mix, but our engines are tuned to fuel/air mix, not oil/fuel.
Referring to oil fuel as rich/lean just confuses matters for the inexperienced.
 
locell

locell

Member
Jan 16, 2010
215
0
16
mesa
thanks, ya, it does sound like an air/fuel thing. I should of phrased it differently. "run the ratio on the fuel mix with as little oil as possible"
 
Ibedayank

Ibedayank

New Member
Oct 29, 2011
1,171
0
0
Columbia Tennessee
locell said:
Run the engine as lean as possible (less oil in the gas), get a 36 took sprocket on the rear, don't run a chain tensioner on the drive side, put it on the pedal side. make sure everything is well lubed and moves smooth, I got my cranbrook to 59 mph with this in mind.
Click to expand...
being that he is using a FOURSTROKE there is no oil in the gas to start with
......
 
You must log in or register to reply here.
Top Bottom