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intakes with or without crossover


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The crossover adds to crankcase volume. That could be good or bad, depending on the motor and application. It seems like the crossover would be a good idea to me, but we don't run them on drag motors. Most people don't. Maybe they are better for on and off throttle, rather than WOT.

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I think on the crankcase volume, the less the better because you get more velocity from the air/fuel mix for drag racing. Not sure about mx or trail riding. Tim at Titan Racing who is a two stroke genius had a whole discussion on it on Planet Sand.

 

That being said, most probably don't know or try to check their crankcase volume.

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Wouldnt the intake have to be on the other side of the reeds in order to add to crank case volume? I just figured it helped ballance each side out when idling and cruzing at low speeds.

Hmmm, well bikes that don't run em idle and run well at low speeds as well. Wonder what yamaha was thinking when they made this feature.....with no for sure answer guesss I'm back at square one. Thanks for the help tho guys. Anyone else with some more clarity?

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One therory is it is to help keep fuel from escape the engine before the reeds close. It uses the incoming force of the opposite intake, the crossover tube transfers it to the other side to try to force any outcoming fuel back into the engine.

It works on similar principle as a boost bottle.

 

Oh ok think that's a lil better explanation......so are u saying that intakes built for a crossover is a better way to go?

Edited by aleyesonme
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I just installed chariot reed cages and chariot's non cross-over billet intakes.

I tuned them, sync'd them and I can't tell the difference.

Thing flat out rips with no low speed, mid speed or high speed issues at all.

 

Going to install chariot's billet timing plate and advance the timing to +4* tomorrow morning.

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I just installed chariot reed cages and chariot's non cross-over billet intakes.

I tuned them, sync'd them and I can't tell the difference.

Thing flat out rips with no low speed, mid speed or high speed issues at all.

 

Going to install chariot's billet timing plate and advance the timing to +4* tomorrow morning.

yeah thats what im getting at.   seems to act the same with or without one.  just dont know the politically correct reason

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+4* on the plate made it even crisper with more power throughout the rev range.

One thing is, the stock cylinders are lacking in top end.

 

As far as stock intake w/cross-over tube to non cross-over billet intakes,

I can't tell any difference whatsoever.

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the only reason the banshee has it is because of a factory yamaha racer demanded it on a dirt back way back in the 80's  the "boost bottle" was his thing.  the 3 wheeler had it  and the banshee  and a bunch of dirt bikes.  a few years after that the factory ditched it on the dirt bikes and that was the end of that.  welll because they didnt want to retool for the good ole money making bitch that was banshee  they just left it on there.

 

no other 2 stroke has a "crossover tube " that i know of.

 

to make it simple  more crankcase volume hurts performance, but can lessen the pipe "hit"  now back in the 80's pipe hit was super violent making it hard to control some dirt bikes.  of course they came a very long ways in that regards and lessening crank volume didnt stick.. so before everyone goes runnign out to the garage to measure their crank volume  modern 2 strokes have pretty minimal crank volume issues.  most dirtbikes even end up with stuffed cases and crank stuffers to lessen it even more..  that helps keep the fuel/air moving and going into the transfers where it belongs..   just my view on it.

 

the "intakes" that have the tube are just asking for air leaks.  most DO leak eventually ( sometimes right out of the box  WTF)  and are total crap as far as i'm concerned 

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