more speed!!!?

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jtbarnes89

New Member
Sep 1, 2010
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Tucson
ok i have a 26 beach cruiser with a 66cc grubee skyhawk 2 stroke with a spookytooth cycles 36 tooth sproket on it.... im only getting like 30 and then 35 down hill.. i want to get up to about 40 or faster on flat land... any ideas?
 

WdSjw

New Member
Sep 7, 2010
35
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CA
I wonder if you could go a lot faster if you installed a fixed gear flip flop road bike wheel on the back, you know the kind with a small sprocket on both sides? One free wheel and one that pedals both forwards and backwards on the motor side. I think this would dramatically increase your top speed, but safety ??? Has anyone actually done this yet?
 

BarelyAWake

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Jul 21, 2009
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The only way that'd effect yer speed is through the gearing - which remember doesn't increase power so it'd be a give & take situation, you'd lose acceleration for speed or vice versa...

...which given it takes exponentially more and more power to overcome wind resistance & that he's reaching pretty much the known max speed for a stock or even semi-stock HT - gearing alone ain't gonna do eet ;)
 

WdSjw

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Sep 7, 2010
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My instructions call for drilling holes in the muffler to dramatically increase horsepower ??? I am too scared to do this yet. How does this work and how much more power could we expect?
 

BarelyAWake

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Jul 21, 2009
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My instructions call for drilling holes in the muffler to dramatically increase horsepower ??? I am too scared to do this yet. How does this work and how much more power could we expect?
You're simply reducing back pressure, while the stock muffler can be unduly restrictive - it's only a marginal improvement at the cost of a louder ride... check out "expansion chambers" if you want the biggest performance return for the money ;)


What about using an octane booster or airplane gas?
While ya might get cleaner fuel, high octane gas is for high compression engines... which these china kits are anythin' but lol
 
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jtbarnes89

New Member
Sep 1, 2010
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Tucson
And get a shift kit and at least a 3-speed hub....you might even hit 50mph:D
i like the three speed hub idea thats a good one.. but will it hold in the pressure of the motor?
and wat do u mean by shift kit?? i didnt know u can out shift kits on these bikes
 

WdSjw

New Member
Sep 7, 2010
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CA
My coaster motor bike is pretty smooth and stable right around 15mph-25mph; I feel like if I crashed or some component failed at those speeds I would probably be okay. Too much faster and I think a real motorcycle is in order. In fact, motorizing my bicycle has caused me to seriously consider buying a real motor cycle.
 

WdSjw

New Member
Sep 7, 2010
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CA
it's not that, i just don't want to get hurt again on a bike

I hope you don't get injured either. The last time I crashed my bicycle (non motorized) I was going 25-25 mph (fixed gear) and I went head first over the handle bars, did a flip landed on my back with a back pack on. I didn't even get hurt and my laptop that was in my back pack didn't even get damaged. The bicycle accident before that (non motorized) really hurt a lot. A car made an illegal left hand turn right in front of me and I hit the windshield at about 20mph and I walked away, luckily, but I was sore for about 8 months from that one.

Anyway, you can ride as fast as you want. I just don't want to see anyone get injured.
 

WdSjw

New Member
Sep 7, 2010
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CA
Sure, I think the kind of oil I use is giving me more power :) I bought some Stihl oil, for 2 stroke chainsaw engines and added it to my gas. It's a lot darker oil than the other kind I was using, which made the fuel mix more blue, the Stihl oil makes the mixture black. Anyway, my top speed is like 5 mph faster now and my engine makes a different more powerful sound :-/
 

jtbarnes89

New Member
Sep 1, 2010
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Tucson
Port it, add an expansion pipe, rejet the carb, higher flow air filter. Maybe upgrade to a CNS carb. A nicer intake will help for flow, too. Beyond that, you're looking at modding on a Puch E50 head.

Edit: oh, and if you're prepared to go 40, you'd better invest in some sprung forks and make sure you have good brakes and good hubs. Otherwise, you're liable to go from 40 to 0 in a rapid and uncontrolled fashion.
its already jetted for this elevation and a cns carb wont help much cause im running a rich mix anyways.... but wheres a good plae to find a cheap expansion chamber exhaust? and high performance air filter? i know of sick bike parts and spookytooth.. anywhere else?
 

jtbarnes89

New Member
Sep 1, 2010
17
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Tucson
Gasbike has an expansion pipe, but it's not much cheaper than the SBP kit, and it's just one of those banana ones with no silencer. You might be able to find a pocket bike exhaust on eBay cheaper, and modify it to your liking.



What size jet? Did you drill and solder it or replace it entirely? I'm confused on why a "rich mix" would negate any benefits of a CNS carb, too. Care to explain?
the only advantage to a cns carb is that u can regulate ur fuel mixture for higher rpms