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[nacree]

My 72 nikasil bore with 6.9 primary gears probably gets pretty darn close but really loses power up hills- I have an aftermarket speedo but I have not installed it yet but it buries the needle on the stock cluster pretty well.

Later,

Nathan

[da808nanospeed]

i only can hit 60mph on flat, 45mph hill climb. my bike 0-45mph is quick after that it pick up speed real slow

[Trafficjamz]

tospreeornottospree's new scooter goes 65mph pretty easy. But I would not hold it at wide open for more than a minute or two because of high head temps.

50mm bore on a 44mm ministroker 28mm carb 6.9:1 primary gears and a 80/90 tire.

This speed is verfied by gps and the vapor trial tech gauge.

[Wheelman-111]

Greetings:

My Nikasil with very low nominal (115-ish) compression exceeded 60 in good weather, but I'm not sure it'd survive at that speed all the time. This is with 8.4:1 gears and a lot of the goodies. A "consistent" 65 is asking a lot; I'd expect the scooter would need to be capable of over 80 if it were asked to cruise at 65.

Others have reported better performance with the Italian kits, particularly the Corsa by Polini, which likes to rev and seems to survive that sustained high RPM. With the power unleashed by an exotic pipe, I have little trouble believing 70, but reports of 75 or more surely were conducted downwind, if not downhill.

Racers have a different set of priorities from the daily Riders, so a full-on take-no-prisoners 72cc might run faster. But for how long?

If you want that consistent 65 MPH reliably, you might consider more displacement, like a 250cc. Otherwise you can resort to the method many of us use: Lie.

[Munstah666]

Numerous guys from hawaii hits that with a fully ported corsa kits, ask tru72?

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[nacree]

I think you would get there with longer gears that 8.44's. Get some of Daywot's 6.9 primaries and try them out. They install without having to press a gear on or off the main shaft. I think the 6.9s would get you to the top speed you want but you are going to lose some torque.

[Munstah666]

I think you would get there with longer gears that 8.44's. Get some of Daywot's 6.9 primaries and try them out. They install without having to press a gear on or off the main shaft. I think the 6.9s would get you to the top speed you want but you are going to lose some torque.

Agreed, you need at least 6: ? gears to hit that speed. You will lose some low end but not that bad If tuned right.

[sanjuro]

My MHR Replica setup with the following:

tm24 carburetor (35 slow jet and 160 main jet)
malossi variator (6.0 gram rollers), delta clutch, clutch bell, and kevlar belt

I'm gear limited right now to 60 mph, and running 9.71:1 kitaco primary gears. The pipe is excellent for the midrange, and it's got more but I probably need to put in 9:1 gears to see more top end. It gets to 60 mph in a hurry.

Here's the pipe that was used in that setup:
Burial pipe from Japan.


Unfortunately, that pipe is no longer made.

[Trafficjamz]

My MHR Replica setup with the following:

tm24 carburetor (35 slow jet and 160 main jet)
malossi variator (6.0 gram rollers), delta clutch, clutch bell, and kevlar belt

I'm gear limited right now to 60 mph, and running 9.71:1 kitaco primary gears. The pipe is excellent for the midrange, and it's got more but I probably need to put in 9:1 gears to see more top end. It gets to 60 mph in a hurry.

Here's the pipe that was used in that setup:
Burial pipe from Japan.


Unfortunately, that pipe is no longer made.

60mph on 9.7:1 gears At what RPM? must be like 10k is that a 72cc setup?

[vette66_00]

If you want that consistent 65 MPH reliably, you might consider more displacement, like a 250cc.

All day everyday and at 62 mpg.

[sanjuro]

My MHR Replica setup:

I'm gear limited right now to 60 mph, and running 9.71:1 kitaco primary gears. The pipe is excellent for the midrange, and it's got more but I probably need to put in 9:1 gears to see more top end. It gets to 60 mph in a hurry.

60mph on 9.7:1 gears At what RPM? must be like 10k is that a 72cc setup?

I don't have a tach, so I can't say. The MHR Replica is 72cc, and according to the product info is supposed to rev up to 10.800-11.800 rpmÔÇÿs. The Burial pipe is extremely high revving and I'd now only consider running a Burial, Zero, or Windjammer chamber pipe.

[evilone]

I got a gps verified 69.8 on my mini-stroker build. Ported Malossi 72cc, pg long, and 8.4:1 gears. I'm sure i could have hit 70 on a longer test ride.

[Wheelman-111]

Greetings:

Astonishing, EvilOne! Flash 4.0 recorded an identical speed, just a little hill-assisted. Right before a hole burned into the piston. That was a Ruima 51mm bore. Evidently the Italian kits are built to a higher degree of precision, or composed of sterner stuff. Or maybe Wheelman just can't tune...

Calculations applied to the Sanjuro's post: I'm working off a wheel diameter of 16.5", 9.7:1 gears and a generous variator "overdrive" factor of 0.75:1. It works out to about 9000 RPM for 60 MPH, but I suspect something is lost to belt slippage. If you use a factory transmission without giant front pulley, the Factory-spec 0.8:1 overdrive ratio nets out to 9600 RPM on the same setup. Still under 10K.

Since even Nikasil can spin up over 10, I have no trouble believing 60MPH on 9.7:1 gears, and I'm sure the acceleration is way better than with 8.4s. However the 10,400RPM I once recorded netted me only 62 MPH and change. Note that I have 8.4:1 gears, so where's my speed?