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rideblue831

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About rideblue831

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    TT Newbie

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    California
  1. rideblue831

    Jetting for exhaust changes???

    <<A better flowing exhaust reduces the restrictions downstream and increases the amount of air pumped thru the engine and each stroke. >> Increased amount of air? How's that? It sucks in one cylinders worth of air on the intake stroke and pushes out one cylinders worth on the exhaust stroke no matter what's on the exhaust side, not counting the effects of valve overlap. <<All of this air comes thru the intake and carb. With more air comes the need to richen the jetting.>> More air? How does it suck in more air on the intake stroke? Are you saying that an engine doing a steady 3000 rpm with a restrictive exhaust is pumping less air that an engine doing a steady 3000 rpm with a less restrictive exhaust, not counting the effects of valve overlap? The intake side only knows it's doing 3000 rpm. Valve overlap is the only way I can see any effect on the intake. If all bikes have overlap then that explains it.
  2. rideblue831

    Jetting for exhaust changes???

    <<your way off base. the exhaust certianly does have a direct relation to the intake.>> Care to explain in technical details instead of just telling me I'm wrong? <<you do know that in over lap the intake and ex valves are open at the same time right?>> Ya, that would have an effect on it but do all bikes have overlap? I'm talking about stock bikes not ones with custom cams.
  3. I've heard people say that when you make exhaust changes you need to rejet. This makes absolutley no sense at all to me. The exhaust and intake systems are completely seperated by the valves and don't know anything about each other. When the piston goes up on the exhaust stroke the intake valve(s) is closed and the exhaust is pushed out. It's as if the engine only had an exhaust valve(s). The jet is in the carb and is nowhere near the exhaust. As far as the exhaust system is concerned there isn't even any intake system at all. It doesn't know of anything beyond the cylinder. When the piston goes down on the intake stroke the exhaust valve(s) is closed as if there weren't even one(s) at all, the intake valve(s) is open and the vacuum in the intake draws fuel out of the carb and into the cylinder as if the engine only had intake valve(s). On the intake stroke the carb knows nothing about any exhaust system or if there even is one at all. It's as if the engine only had an intake side. So what is your take on this?
  4. rideblue831

    WR400 Fluidyne, Unabiker setup

    Can anyone tell me if I can put the Fluidyne radiators on my 98 wr400? They say for 2000 and up. So the question is, will the 2000 radiators fit in the 1998 frame? One call to the dealer parts counter told me ya they're both identicle looking at his parts catalog, then a week later a different guy tells me no they're different part numbers so no go. Won't work. And is it the same radiators in the YZ and WR? Then will the Unabiker guards fit over the Fluidynes ok and finally will the shrouds or radiator covers for the 2000 fit on the 98 tank. The parts guy also told me the tanks were different from 98 to 2000 so the radiator shrouds for the 2000 won't fit on my tank. But I've heard all plastic is the same for 98 to 2000, YZ or WR. I need the 2000 radiator shrouds to fit the Fluidyne radiators 'cuz they are for 2000 which have the angled mount on the radiator. My 98 shrouds won't mount to the Fluidyne radiator unless I cable tie it which I don't want to do, not a very rigid setup. So what it comes down to is that I need a 2000 year radiator and shroud setup on my 1998 WR400. Is that doable? And does it matter if it's YZ or WR radiators and shrouds? thanks <- friend who wrecked bike.
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