Tuning a Non-Variated Moby?

Ϫ‡☄ಬ∞ ƀƖḬƝƊ ƤǂƿƎ ∞ಬ☄‡Ϫ - Hoke from Black Pipes Moped Gang /

i have a romp, it's stock, does 30 all day and night.

non variated though.... am wondering if the stock dimoby clutch can support the added power of a port job and an expansion pipe? i would like to get into the high 30's, what do you guys say?

Re: Tuning a Non-Variated Moby?

There really is nothing wrong with the single speed clutch. Its plenty tough, and will hold up fine. You'll have to make a compromise if you adjust the gearing however.

Re: Tuning a Non-Variated Moby?

Ϫ‡☄ಬ∞ ƀƖḬƝƊ ƤǂƿƎ ∞ಬ☄‡Ϫ - Hoke from Black Pipes Moped Gang /

you mean that the better the engine is built, the higher it will rev, but that the higher it revs, the more likely you are to damage the engine? and by changing the gearing, you reduce the chance of grenadeing, at the cost of having slower acceleration?


Re: Tuning a Non-Variated Moby?

Any cylinder can take a lot of miles as long as you keep it well-lubricated/don't run too lean/don't run WOT constantly.

If you change the gearing for more top speed--- and you have a non-variated, single speed bike-- you will sacrifice low end.

If your riding is usually long-distance with few stops, you'd want to change the gearing for more top speed, that way you could go fast _enough_ without running WOT all the time, reducing the life of your engine.

If you're riding around in a city where you have to stop a lot, sacrificing low end might be a bad thing, besides you might never even want to go 40 if there's traffic or a stop light a block away.

I might be wrong on some of this, but that's how I understand it.

Re: Tuning a Non-Variated Moby?

Dimoby is as tough as the Moby-Matic, absolutely. I've had both apart and can attest the wearable surfaces and structural parts are easily comparable. That said, a variated bike is a lot more fun to drive. It's an easy conversion, too.

Re: Tuning a Non-Variated Moby?

Ϫ‡☄ಬ∞ ƀƖḬƝƊ ƤǂƿƎ ∞ಬ☄‡Ϫ - Hoke from Black Pipes Moped Gang /

howabout this:

isn't there more energy loss overall in the variated set up? i mean, since it is variated, doesn't that mean there are more moving parts that soak up the energy?

what i mean is, take the same engine, tuned perfectly, variated and non variated, doesn't the non variated have more power due to less energy lost throughout the drivetrain? or am i crazy?

i have a variated motobecane that i am working on.

but yea, i ride in the city, i would like to go about 40, low 40's on the bike. i was thinking port, polish, del carb, expansion pipe, might get me there? it already has pretty good get up and go, hits 30 pretty fast. just would like to stay with traffic instead of getting passed....

Re: Tuning a Non-Variated Moby?

Your thought process regarding power loss is not completely correct. Consider all the power loss points:

Engine Bearings, piston friction, other engine losses

Drive belt

Driven pulley bearings

Drive chain

Front and rear wheel bearings, tire friction

The only loss that is changed by a variator is that which occurs at the drive belt, but only in a very minor way. There is no slipping to lose power. Only the size of the drive pulley is changing. As soon as the variator begins to close, in fact, you are decreasing your power losses in the drive belt, as the effective drive pulley diameter increases. This means the belt has to bend less (larger radius). Increasing radius decreases power loss due to belt friction, both internal and external (belt against itself, and belt against pulley, respectively).

Hope this helps


Re: Tuning a Non-Variated Moby?

Ϫ‡☄ಬ∞ ƀƖḬƝƊ ƤǂƿƎ ∞ಬ☄‡Ϫ - Hoke from Black Pipes Moped Gang /

hell yeah julian!! great stuff!! thank you!!!

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