KX 500 Detuning?

[jbehunin]

I recently picked up a KX500 from an older guy. In another post, I asked about the KIPS valve because the bike would not build revs and accelerated really slow. I thought that this was a little strange, so I decided to do some inspecting.

I tore the pipe and reeds off the bike to inspect the head, piston and valve. Everything looked awesome, and everything looked clean.

As I got to looking, the stock reed cage was replaced by a reed cage assembly out of a KX125....

The reeds fit great, but the size of the intake hole is substantially smaller in size....

Would this cause the KX500 to be tamed down?
Just want everyone's thoughts on this!!!!

Thanks!

[DoldGuy]

JB,
Don't think a 125 will fit the 500 as it's mounting is much smaller than the K5. The 250 cage will fit & is smaller than the 500 but I've not tried running it (Kaw Rider has maybe he will chime in).
DoldGuy

[NZ500]

A 500 accelerating slowly? haha. Well at least you know the bike hasn't been worked to hard

I can't remember if I saw it on this forum or a KTM one but there has been a couple guys with constipated feeling bikes that were caused by internal damage in the expansion chamber. I remember someone mentioning some pipes have two walls and once you dent them and pop the dents back out the inside wall can stay the damaged shape (repeating what someone else said, they could be full of it for all I know). The guy who had trouble had a bracket or piece of metal that had come loose and was inside his pipe causing him trouble.

Do you know what carb's on the bike? Is it possible that they've some how limited the accererator from opening right up?

[jbehunin]

It has the stock carb on it, and its jetted pretty good.

All I know is that this bike runs great, starts easily, but just doesnt have the bite that my old CR 500 had. I have ridden a few KX 500's in times past, and this bike doesnt run like the others. Its kinda hard to explain. But after looking at the reeds, the small hole for the intake makes me think that its acting like some sort of baffle.
The guy I bought it from was a little old 68 year old man that babied it.

Plus there are no dents in the pipe. Everything else on the bike looks great.

Im just dumbfounded that someone would want to detune this bike.

[jbehunin]

Here is a pic of the bike. It is a 93 model, and thats the stock plastics and seat cover.

[jbehunin]

I got to looking for reeds and a reed cage assembly on ebay.
This is not what mine looks like.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=150477641964&viewitem=&sspagename=STRK%3AMEWAX%3AIT

These are pics of what came out of my bike.

[NZ500]

Nice bike. Wow I see what you mean lol. I've got my one sitting here (handy having bike in bits in dining room lol). Great excuse to get a Vforce for your beast

Maybe it made him feel younger still owning a kx500 at that age lol. I couldn't imagine my grand dad on a scooter let alone a kx500, he can hardly walk let alone riding one of those

[DoldGuy]

JB,
That valve looks like an FMF Ram Valve from the 250. The small hole you are referring to is called a stuffer which keeps the velocity high.
DoldGuy

[kwakman]

I spy with a keen green eye, an fmf desert pipe.that thing will rip when your intake is sorted.pack spare pants.....

[Roostmad1]

Here is a pic of the bike. It is a 93 model, and thats the stock plastics and seat cover.

Hi,sounds like the KIPS valves aren't opening properly?,when i first got my 86 K5 some muppet had put the KIPS valves in all wrong, just a thought anyway,goodluck

[kaw rider]

Yeah it's funny what you see when you take motors apart that don't run right. I had good luck with the 250 V3 cage for my set-up that i run.

[jbehunin]

well, a few days have passed since I discovered a 250 reed cage was in my 500. Well I bought a true 500 reed cage and intake boot...

well, not to my surprise, it woke the beast up!!

Before I put the tank and seat back on, I popped out the plug and did a compression test. Im not too sure what its supposed to be, but the reading was 110psi.

The front wheel comes up with no trouble now, and I am happy!!!!

Now I just have to get the suspension done!!!!

[Friar-Tuck]

 Good on Ya,
   Another Happy Member

( I'm not sure that sounds quite right... )
   \o/

[snoopjonnyjon]

110psi is getting a bit low. Mine was reading 150psi when I tore mine apart, and still noticed a huge difference when put back together with new parts. It was foolish of me, but I never bothered to compression check the new setup.

[jbehunin]

When I took out the reed cage, I inspected the cylinder. The piston looked good, but I could tell that it had never been replaced. It still has the stock piston in the bike.....

Well I have ordered a new piston kit, and will replace it next week.