Is it possible for a dirt bike to hit powerband twice in a gear? Simple question, and if you don't know what you're talking about then don't answer.

Yes I do know how a 2-stroke engine works.

provided you let off the gas and the rpm drops, and you get on the gas again, you could get into the powerband an infinite number of times.

lol not exactly what I was wondering, more like if the engine could have two jumps in power in each gear, basically like hitting powerband twice.

no unless maybe some one did extreem mods just to make it do that(not reality but theroetically possible). if a bike has some bad jetting issues it might feel like it hits twice

lol EXTREEEEEME haha.

R-Dubya said:

Yes, if it has tandem roller bearings in the muffler.

only if you have aftermarket adjustable powerbands.


they cost extra

i bet an expantion pipe building expert could figure a way out, but you wouldnt really have 2 you would just have one split up by a bad/dead spot, and still might not be possible

I think it could be done, but if you wanted two good powerband hits it probably wouldn't be easy or cheap.

A guy in the Advanced Technical Discussion section turned me on to 'slippy' pipes, which are cable-controlled adjustable expansion chambers.

I think the following setup could get both a low-end and top-end hit:

1) early power-valve motor, like an '85 RM250 or similar
2) high compression head
3) 'slippy' pipe
4) programmable ignition with custom advance curve capability

The head and pipe (fully extended for max low end) could be combined with larger-than-normal amounts of ignition advance and the older motor's semi-old-school porting to get a pretty decent low/mid power surge; an auto clutch set for a high engagement speed would really intensify it. At high revs, the power valve and fully-retracted pipe would combine with retarded timing to give a good top end hit, probably more intense than the lower one.

It would take some work to get right, but I think it's doable. It would make a great final exam for an engine design course. :D

Ray

Mikeb12 said:

You can save money and twist the stock one extra tight :thumbsup:

Mike38 said:

I just installed those! Man what a difference those tandem roller bearings make. I went with the 32mm zinc coated 2.4 oz size. In my opinion the 32mm work much better on the 450. You can really tell a difference when the powerband kicks in. I am running the 2" powerband by the way...In purple...Matches my helmet.:thumbsup:

OH GOD lol it was only a matter of time before this turned into a powerband joke xD

heheheheheheeeeeeeeeeeeeee

You could have a powervalve open up at lets say 5500rpm, close at 6500rpm, and then open again at 7500 rpm and it might feel like the power kicks in twice.

meyermetal said:

well if you twist the stock band 180 degrees so it intersects if will act like it has two powerbands installed.

jbusa8 said:

Hey! I never thought about that...Does it matter if it is twisted clockwise or counter clockwise?:lol::lol::lol::lol:

the power band is when the engine makes the MOST power so there can only be one. it is when the piston is going up and down in time for the blow down of the expansion chamber to re-enter the cylinder

Mikeb12 said:

Fixed.

Darrell41653 said:

counter clockwise only works in reverse.

CORider63 said:

tellin ya, the free mod is better dollar for dollar.

el chupacabra said:

Technically it's when an engine is able to operate efficiently (more than 75% of max. efficiency or so), so technically an engine can only hit once. But physically, if an engine hit powerband and was making 75% efficiency, then jumped up to 90% or more, violently, it would seem like it hit twice. I was just wondering if it's possible to make that actually happen. For what reason? None. Lol.