i want to know, what should i install on my bike before a jackshaft, performance-wise

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xXNightRiderXx

Active Member
Jan 12, 2017
515
229
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Boise
i have been looking at installing a jackshaft for quite some time before i actually got my engine, so i was wondering, what would you guys install to get the most out of the engine before installing the jackshaft?

I have a kent roadtech with an 80cc two cycle engine, zero upgrades, two replacement parts.
.shft.
 
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Jan 21, 2015
610
25
18
Portland, Oregon
Re: i want to know, what should i install on my bike before a jackshaft, performance-

new fuel line, spark plug boot, fuel filter, air filter, custom expansion chamber (big one), port the engine, sand down the cylinder head, replace all the mounting hardware, to name a few.
 

xXNightRiderXx

Active Member
Jan 12, 2017
515
229
43
Boise
Re: i want to know, what should i install on my bike before a jackshaft, performance-

those seem pretty basic. what im talking about are things that will let me get the most i possibly can out of this chinagirl, and im willing to spend up to quad what i paid for the kit.
 
Jan 21, 2015
610
25
18
Portland, Oregon
Re: i want to know, what should i install on my bike before a jackshaft, performance-

those seem pretty basic. what im talking about are things that will let me get the most i possibly can out of this chinagirl, and im willing to spend up to quad what i paid for the kit.
Some of those are basic, but not breaking down every 50 miles is a huge plus. Also, a big, well tuned expansion chamber is pretty much the single best thing you can do to get more power. Oh yea btw, none of the chinagirls are 80cc. The ones that say they are 80cc are actually 66cc.
 

Agreen

Member
Feb 10, 2013
792
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18
Southeastern GA
Re: i want to know, what should i install on my bike before a jackshaft, performance-

He gave you the right list. I'd only add a CRmachine Fred head, instead of sanding the original one down.

If you're real serious about performance, download a copy of Gordon Jennings's 2 stroke tuners handbook. You will learn about proper port timing, size, and shape, as well as everything else needed to make a 2 stroke scream.
 
Jan 21, 2015
610
25
18
Portland, Oregon
Re: i want to know, what should i install on my bike before a jackshaft, performance-

Also, if you don't get a jackshaft, you'll want to get a hub or disc sprocket adapter so you don't rip the spokes out of your wheel.

And you will probably have to get a smaller carb jet as well, most of the 2 strokes run so rich out of the box that they'll 4 stroke even at the leanest carb setting.
 

xXNightRiderXx

Active Member
Jan 12, 2017
515
229
43
Boise
Re: i want to know, what should i install on my bike before a jackshaft, performance-

Well, now I have a big problem with this engine. At idle, the rpms fluctuate, though I'm not touching anything. Also, when I try to engage the clutch, I do like you normally would, slowly with a bit of gas, but the motor acts like its getting too much or too little, idk which, and tries to die. What are the causes for these issues?:-||

Edit: I feel I should have added this in the beginning, but im looking for a good balance between speed and torque, favoring speed. Also, if there is anyone in Las Vegas who can help, I would really appreciate it. I'm also thinking of building a jackshaft instead of buying a kit. I just installed rubber grips from a phone mount that seemed sufficient, and vibration is definitely around 25-30% what it used to be.
 
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Tyler6357

Well-Known Member
Mar 15, 2012
1,293
294
83
Santa Barbara, CA
Re: i want to know, what should i install on my bike before a jackshaft, performance-

An upgraded exhaust pipe is probably the best thing you can do to get the most out of a china girl with respect to performance.
 

wing nut

Member
Aug 9, 2012
128
3
18
warren p.a.
Re: i want to know, what should i install on my bike before a jackshaft, performance-

if your that serious & you have the $$$ then look at these
http://www.arrowmotorizedcycles.com/index.html
i have an older arrow 4.5 street racer & it did 45mph out of the box
...if you have a rpm fluctuation issue , you may have an air leak some where
 
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Cylon

Member
Jun 26, 2015
346
9
18
Maine
Re: i want to know, what should i install on my bike before a jackshaft, performance-

There is no replacement for displacement. You can do a lot of work and gain just a little with these engines but the more you do the less reliable it will be. My wifes stock bike ran great for over a year with minimal work, just the basics. My bike on the other hand which I spent over 1500 usd now to build up over and over again. It constantly has problems. Bicycle parts can only take so much.
 
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Cylon

Member
Jun 26, 2015
346
9
18
Maine
Re: i want to know, what should i install on my bike before a jackshaft, performance-

As parts break 20 dollars here 50 dollars there it adds up. Like with upgrading cars its just not worth it. It cost to much over time, I witnessed it myself with my build vs my wife's stock bike that never dies. I guess the old saying is true if it aint broke dont change it.