more tork

mike carter 2

Member
Nov 23, 2011
253
13
18
west virgina
has any one realy built one of these little motors for more tork ? are there different port timeings ? any tricks? i allready added header leangth raised the compresson some rm 60 x chamber, reed valve, ported piston. the bike wiil fly. pulls pretty hard now but i live on a hill and want more bottom end
 

sbest

Member
Nov 3, 2015
343
2
18
Nova Scotia
Long pipe "Poopoo" exhaust' more compression, (wide ported) cylinder lowered and deep camber RSE head did it for me. Could pull away from a stop with 44t sprocket, but only had 35kph or so max speed.

Steve
 

sbest

Member
Nov 3, 2015
343
2
18
Nova Scotia
hey sbest what do you mean by a "lowered cylender "
Remove the studs, cover the crankcase and file the basegasket surface smooth.
Now seat the cylinder to the crankcase using no basegasket, just ThreeBond or Yamabond sealer. You may need to make some adjustments to the cylinder head with gaskets or chamber cutting to keep the proper squish height. Result is dropping the ports 0.025" or so and a lower rpm powerband and more torque.

Steve
 

mike carter 2

Member
Nov 23, 2011
253
13
18
west virgina
im running a gt 80 engine. a 40 tooth gear. bike will pull from about 3 or 4 to about 30 or 35.i had a 36 tooth sproket on it and could get to over 40 but im trying to make more bottom end and not lose to much top end. bike pulls hard now
 

mike carter 2

Member
Nov 23, 2011
253
13
18
west virgina
come on guys , more tork meanes a quicker bike.quicker means faster,i think you can allways tune for more top end . if i can build enough bottom end i can change from 40 to 36 rear gear agian . i was going over 40 easy with the 36 cog. there has to be more secrets. dnut
 

sbest

Member
Nov 3, 2015
343
2
18
Nova Scotia
come on guys , more tork meanes a quicker bike.quicker means faster,i think you can allways tune for more top end . if i can build enough bottom end i can change from 40 to 36 rear gear agian . i was going over 40 easy with the 36 cog. there has to be more secrets. dnut
I would think "tork" is torque spelled phonetically, which would refer to the pulling force of the motor. More torque does not mean quicker, generally more horsepower does mean quicker and often means more top speed too, but circumstances can vary. Torque is the hp/rpm*5252, which means it always equals the hp at 5252rpm. Quicker does not mean faster, and often the two are diametrically opposed. Gearing for quick will reduce speed and vice versa.

I was able to get just over 40mph with a 44 tooth. Imagine what I'd get with a 36t? That can be done with ratio and proportion actually, 44x40/36=48.8mph. Key word is imagine, you have to have the hp to get it there.

Tell me what I can "allways tune for top end"? I'd love to know.

Steve
 

mike carter 2

Member
Nov 23, 2011
253
13
18
west virgina
thanks to people like you theres a ton of information on this forom on how make more top end .im kinda a newbie .i live on a hill. i have a gravle driveway.rite now i have to turn into my driveway at high speed ;bounce up the rough part. wait for just the rite speed to start peddling,peddle like **** and try to get to the top. no doubt anyone watching would laugh there a__ off. it even makes me grin .o yea. im 57
 

sbest

Member
Nov 3, 2015
343
2
18
Nova Scotia
thanks to people like you theres a ton of information on this forom on how make more top end .im kinda a newbie .i live on a hill. i have a gravle driveway.rite now i have to turn into my driveway at high speed ;bounce up the rough part. wait for just the rite speed to start peddling,peddle like **** and try to get to the top. no doubt anyone watching would laugh there a__ off. it even makes me grin .o yea. im 57
Hey Mike you old fart!
I'm only 56, but remarkably immature for my age...

Steve
 
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mike carter 2

Member
Nov 23, 2011
253
13
18
west virgina
what i mean by more 'tork' is that it will make your bike quicker in the curves .comeing out of curves going into straghts. helps make up for some straightaway speed.more bottom end could make up for a lot in the long run.
 

Chaz

Well-Known Member
Jun 3, 2012
1,004
70
48
Vancouver, British Columbia
Mike, the technical word you're looking for is oomph. I'm seeking the same. I am going to install an expansion chamber tuned for low and middle and get a smaller rear sprocket. I only need to go about 33 mph but want to get there fast and cruise at a bit lower rpm.

Dave Letterman used to say "it ain't the horsepower, it's the torque."
 
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