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Discussion Starter #1
any thoughts on a bore and stroke kit for the ex500? also, has anyone ever seen and/or heard of a undertail exhaust for the 500?
-thanks
 

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I played around with the idea of fabing up an undertail exhaust. However the problem that arose for me was that where most bikes with undertail have more room around the swing arm, shock, tire to route the exhaust up thru there. So for the time being I gave up. But you might be able to adapt so of the others bikes exhaust to get the room u need.
 

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I have thought long and hard about building an undertail exhaust for my EX but I can't for the life of me see a good way to get the pipe around the swingarm without it sticking out in a stupid position. There is just no room in there to pass the required area exhaust pipe without repositioning a lot of stuff and I don't want to bring the pipe outside the frame just to bring it in again. It may be possible with an eccentricly shaped pipe or a few smaller diameter ones but that's more work than I want to undertake.

I think we're skunked on this one. All is not lost though. There may be enough room behind the oil pan for a trapped exhaust with a short stub pipe. Kind of like the 650. I'm going to be looking at it this summer. The shape is pretty weird but I can draw metal to shape or even shoot for CF. Gonna have to fire up CosmosFlow first though!
 

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In this day of CNC machining custom pistons are easy and cheap. LA or Northwest can do custom sleeves to any dimension you want, again cheap and easy.
For a stroker crank it is simple to turn the journals off center at 26mm, giving you a 1.7 -1.9 mm stroker. Use rods from a Suzuki GS or Katana and stock pistons and rings. Adjust your compression with base gaskets and copper head gaskets.
I have a stroker crank if you want to try.


Those parts are easy. What are you going to do to stop the thing from spinning rod bearings?

What is the undertail exhaust for?
On a street bike it is 100% poser...ZERO VALUE.
What an undertail exhaust is meant to do is fill in the vacuum behind the rider (at speed) with exhaust gases so the draft is less effective. If you got people drafting you on the street you got other problems that an undertail will not cure.
 

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bitzz said:
What an undertail exhaust is meant to do is fill in the vacuum behind the rider (at speed) with exhaust gases so the draft is less effective. If you got people drafting you on the street you got other problems that an undertail will not cure.
Never would have guessed that. Ever. I thought it was purely aesthetic
 

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I've heard others complain that it was one of the worst things they ever did. Idea being that the high weight slows turn in. One of the aftermarket cans makes their biggest performance claims based on that, being light weight. I've got no thoughts from direct experience except that tucked in, it might survive a mild low side.
 

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Discussion Starter #9
bitzz said:
Those parts are easy. What are you going to do to stop the thing from spinning rod bearings?

What is the undertail exhaust for?
On a street bike it is 100% poser...ZERO VALUE.
What an undertail exhaust is meant to do is fill in the vacuum behind the rider (at speed) with exhaust gases so the draft is less effective. If you got people drafting you on the street you got other problems that an undertail will not cure.
as far as spinning rod bearings, i havent gotten that far. i dont know a whole lot about engines, so i figured working on my 500 is a good start. abeit bore and stroking is not a wise first step to learn.
and the exhaust? ive always liked the way they look to be honest.
 

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If you want a stroked out ex500 buy the Ninja 650, otherwise don't do it.
 

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As far as a bore kit, I'd agree witht the last post, not worth it on this bike. If you're trying to squeeze more HP out of the EX, you're better to buy a real sport bike. As for under tail exhaust, it's a waste of time, and I'd personally never put an undertail on a bike. You lose power pushing the exhaust up that far (however minimal), and it raises your center of gravity; there really isn't any advantage (unless you're talking about whatever that negative pressure idea was). The best exhaust is an underbody can, like you find on the new 650, or on a Buell.
 
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