Good Sprocket Ratio

GoldenMotor.com

PR3C150N

New Member
Aug 27, 2010
69
0
0
NSW
Hey. Is 3:1 a good Ratio for speed? This is with the 36 speed Sprocket. How much faster will you get compared to a 44 tooth sprocket i currently have on at the moment. i want the smaller one because i cant get a shift kit because i don’t have gears on my cruiser. so wondering if the 36 tooth is a good investment? because my engine is breaking a sweat when im goin top speed ( 42 km ) and it sounds like it wont go any faster or my bum and hands will fall off because of vibration haha =]
 

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
7,271
1,810
113
Los Angeles, CA.
36T sprockets aren't all they're cracked up to be... They don't pull up hill very well (unless you only weigh 130 lbs) & many engines just don't have the power needed to get a bike up to full speed with that high of a gear.
I prefer 40T sprockets... They are the best of both worlds; a little more top speed & they still have good hill climbing power. ;)
 

7t2cougar

New Member
Sep 12, 2010
2
0
0
California
i just got a 36 tooth sprocket and i havent had any problems but theres no hills around me i weigh about 150. it increased my speed about 4 or 5 mph from the 44 tooth. i just put a garmin in my back pack to get the speed. ive gotten 35 so far.

the best thing ive done for speed and acceleration was port the exhuast and intake ports. it was amasingly better
 

KCvale

Well-Known Member
Feb 28, 2010
3,966
57
48
Phoenix,AZ
What size motor?
With a 66 you can get some extra speed, but with a 48cc, well, gearing it even higher won't help without performance mods or gears, and it would be miserable to ride under 15MPH.
 

PR3C150N

New Member
Aug 27, 2010
69
0
0
NSW
66cc engine i have. well the 36th tooth might give it a bit more speed and free the engine up so its not just about dying when i reach top speed. this is my alternative to a shift kit because i cant get one because mine don’t have gears
 

7t2cougar

New Member
Sep 12, 2010
2
0
0
California
i have the 66. like i said the best mod ive done is free. just port the exhaust and intake ports . that drastically improved my acceleration and top speed.
 

BarelyAWake

New Member
Jul 21, 2009
7,194
21
0
Maine
http://motorbicycling.com/f52/basics-port-polish-port-matching-16646.html

"Porting" one of these HTs won't actually gain you a pronounced power increase as you're limited by the ID of both the intake & exhaust manifolds, the stock ports are already far larger. Attempting to enlarge the intake/exhaust/transfer ports to any significant degree is somewhat hazardous with little potential gain - you run the risk of altering the timing, flaking the cylinder liner and/or hanging a ring. They are however quite rough & a lil cleanup will help your motor run smoother.

Port matching is a different story altogether - the manifold's mounting flange & gasket can be at least 20% smaller than even the ID of the rest of the manifold, enlarging it to match (as much as possible) will in fact help quite significantly...

An expansion chamber ona two stroke isa must btw - that gets ya the most "bang" for the buck w/o a doubt ;)
 
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Prasinos

Member
Dec 1, 2008
261
0
16
California
I used to use the 36 and it worked great for me (220lbs). I don't plan on starting at the bottom of a hill and the 36 gives you great power from 20-30 allowing you to take hills at speed. After i got a tuned pipe i only helped the motor on the steepest of hills.
 

DudeZXT

New Member
Jun 20, 2010
115
0
0
Lexington, KY
I used to use the 36 and it worked great for me (220lbs). I don't plan on starting at the bottom of a hill and the 36 gives you great power from 20-30 allowing you to take hills at speed. After i got a tuned pipe i only helped the motor on the steepest of hills.
I second this notion, although I only weigh ~200.
 

KCvale

Well-Known Member
Feb 28, 2010
3,966
57
48
Phoenix,AZ
An expansion chamber on a two stroke is a must btw - that gets ya the most "bang" for the buck w/o a doubt ;)
I have to agree with BA, an X-chamber makes a staggering difference for under $100 delivered from most anyone.
But sure, keep the ports matched and pipe free of debris best you can, and don't forget the gaskets!
 

breno

New Member
Aug 19, 2010
411
0
0
Syd. OZ
I used to use the 36 and it worked great for me (220lbs). I don't plan on starting at the bottom of a hill and the 36 gives you great power from 20-30 allowing you to take hills at speed. After i got a tuned pipe i only helped the motor on the steepest of hills.
Same as you mate only a skyhawk 70cc with a grubbee pipe, shorter/bored out intake, ported intake and exhaust manifold, with the 36tooth she's haulin along couldnt be happier. Personally i chose the 36 tooth for the long rides I have to do but otherwise I'd be going the 40 for more acceleration.