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Discussion Starter #1
When someone says MX motor or TT motor, what does TT mean? I get MX is a Motocross set up (low and mid range power less on top).

what does a “dune” set up look like? Is it more of a MX set up or something else?

how does a MX dyno sheet look compared to a “dune” dyno sheet or a TT dyno sheet? (whatever that is)
 

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I will define the terms in today's world:

1). Dune = Duner, Sand Machine, Climbing Hills made of Sand
2). MX = Motocross
3). TT = Dirt Track with Left & Right turns, relatively Flat, with minimal Jumps in both Height & frequency. Back in the 1900's it meant Tourist Trophy.
4). FT = Flat Track, Oval Racing
5). Drag = Drag Racing, Straight Line Racing

All the 250R engines are basically the same, except for each discipline the variables that change are: Porting, Port Timing, Head/Dome, Pipe, Intake, Reeds, Carburetor, Fuel, ect...

From 1). to 5)...the engines increase in higher performance increments; Dune engines are closest to all around performance builds to Drag engines being the most radical.

Carlos
 

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Discussion Starter #3
That’s very interesting. I would have guessed that a dune bike would have been closer to a TT or FT as you have described them.

So what I want in a “dune” bike and a drag bike, well they don’t really go together. :unsure:

If that’s the case, if you build the same CC engine and set up one for dunes and one for drag and compare max RPM and max MPH between the two, how much difference would there be in max RPM and max mph?
 

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That’s very interesting. I would have guessed that a dune bike would have been closer to a TT or FT as you have described them.

So what I want in a “dune” bike and a drag bike, well they don’t really go together. :unsure:

If that’s the case, if you build the same CC engine and set up one for dunes and one for drag and compare max RPM and max MPH between the two, how much difference would there be in max RPM and max mph?
No compering a Duner to a 'real' Drag engine; completely different setups. Just the most basic differences are Fuel, Compression, Porting, Timing, Pipe, Intake, Carb, ect...the details are to many to list or discuss. TrQ & HP curves are totally different.

Also keep in mind a Duner has to live for extended runs of 20 mins to 2-3 hours at a time. A Drag engine lives in the Run neighborhood of 3-5 seconds at a time.

Carlos
 

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Discussion Starter #5
I understand that the engines will be set up completely different, and maybe comparing a drag motor to a dune motor is such an extreme comparison that it can’t be done.

So I will state my question this way:
If you took a 250 cc duner and a 250 cc flat tracker out to the salt flats and raced them which would have the higher rpm/top speed and what would you speculate the difference in RPM/top speed to be?
 

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I understand that the engines will be set up completely different, and maybe comparing a drag motor to a dune motor is such an extreme comparison that it can’t be done.

So I will state my question this way:
If you took a 250 cc duner and a 250 cc flat tracker out to the salt flats and raced them which would have the higher rpm/top speed and what would you speculate the difference in RPM/top speed to be?

The FT setup being built for more mid to top end would pull on the Duner...neither would necessarily be a function of more or less RPM's, or top speed, however; in theory the FT should be going faster with equal gearing towards the end of the run.

Carlos
 
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