KX500 too slow!

Discussion in 'Big Bikes' started by 92cr, Dec 10, 2002.

  1. nickx

    nickx Member
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    Oh yeah, I think the bike is mostly stock but does have an FMF gold series Fatty pipe on it. So far, so good.


     
  2. nephron

    nephron Dr. Feel Good

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    Well, who woulda' thunk it?

    I can't believe you could watch a video off of Destry's site and think your broken-powervalved KX500 ran the same. They're extremely sensitive to jetting, so a powervalve problem would make one run like an xr50. :|
     
  3. Hick

    Hick Pro Class
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    Top speed should be around 90 or 95.

    The power valve is located in the barrel between the cylinder and exhaust port. It changes port height (and maybe volume??) at different RPMs to create a broader delivery of power. There is a cover on the side of the cylinder that houses the linkage that operates the valve up or down based on engine RPM. Non-power valve motors like the Banshee 350 tend to have a narrower power output since the port location is fixed and will tend to make the best power over a narrower flow rate/rpm range. A power valve is one of those have cake and eat it inventions IMO.

    The only real issues w/ this bike I'm aware of are they do tend to blow head gaskets more easily than other bikes, and they can be difficult to jet to run cleanly. Also, as somebody already noted, the welds on the stock pipe can crack. Of course all that vibration doesn't help.

    On my '99 I also had a shift cam pin fail, but I've not heard of anybody else having that problem, it was only about a ten dollar part.

    Hope this helps.
     
  4. nickx

    nickx Member
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    Yeah, that helps alot. Just took it out for the first time today(out of my subdivision) and opened it up, this thing is scary fast, and vibrated the hell out of my arms, not like my Honda 400ex. I like it. I found out it is a 99 not a 2000, but very clean. The head gaskets are leaking coolant, which I noticed after todays run, the lower and upper gaskets. Also I need a new rear tire, less than 50% left, can't hook up at all. I have the FMF gold series fatty pipe on it so I don't have to worry about broken welds. Thanks for all the info. Oh yeah, do you know if they make a better gasket set out there to keep from leaking coolant? I had gotten 2 upper gaskets sets and rings along with the bike so I do have back-ups.
     
  5. nickx

    nickx Member
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    Does anyone out there know if anyone makes any anti-vibration mounts for the engine? I would think fabricating some rubber bushings in between the block and frame brackets might help a little. As for the leaking headgaskets, they are leaking externally, is that the problem they have with the 500's?
     
  6. kmac

    kmac Member
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    Away for Christmas. I think stock jetting is 58 pilot/175 main. If you had a 60 pilot in there, that'll be rich. For sea-level, I'd go 170, notches on needle are set so that the lower the needle sits, the leaner you are. try 58 pilot/170 main and see how you do. Pretty hard to cook it anyway, but don't get carried away. My plug is grey/dry at my setup, MIGHT try a 55 pilot or 165 main next summer, but will stick with current setup early-season.
     
  7. demographic

    demographic Pro Class
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    I have heard that when the frame is getting a bit long in the tooth the two alluminium plates (yep the triangular ones with three bolts in it) that run from the frame to the cylinder head can put tension on the head and so the head gasket weeps.

    Aparently the way to cure this is by taking the plates off and then drilling the holes that the bolt that connects it onto the head out to a slightly larger size then fitting it all back together.

    I am pretty sure that tip is in Eric Gorrs book also
     
  8. marc owens

    marc owens Rookie
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    Anyone have a kx500 for sale?
     

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