92cr

Member
May 18, 2002
96
0
I just bought a 92kx500 and i rode it yesterday for the first time. I have to say I came away less than impressed.It has a new top end and crank bearings and seals so the motor is totally fresh. I know I couldn't rev it real hard cause it wasn't broken in yet but the mid range seemed really flat and blubbery.It has a pro-circuit pipe and silencer which I've heard is smoother than the FMF but I can't imagine a simple pipe swap making it anywhere near as hard-hitting as my old 86cr500 .I haven't had time to fuss with the jetting but the bike has good snap right off idle and into the lower midrange and then it just seems to load up and not pull as hard as it should.Any help would be appreciated as I really like the rest of the bike.
 

Camstyn

LIFETIME SPONSOR
Oct 3, 1999
2,247
2
You might check to see that the powervalve was installed properly.. The punch marks on the gears were not on the correct teeth with my KX250, so when I reinstalled the powervalve (by the manual), it was not opening properly. Just a possibility.

Otherwise, it's most likely a jetting issue..

Another thought, my KX500 would start to get very blubbery on the mid-top, a new spark plug would always take care of it.
 

kmac

Member
Jun 11, 2002
13
0
I agree with Cam Mitchell, check the power valve. My '91 KX500 is an animal show when it runs clean. I'm running 55 pilot 168 main needle dropped on notch to 4th position @ +/- 3000', +/- 75 degreesF
 

Gman

Member
Nov 30, 2000
35
0
Have fun. To check the power valve teeth and timing you have to pull the cylinder! You can allways look up in the exhaust port and actuate the PV from the linkage by the cylinder base to see if it's in the ballpark.
 

92cr

Member
May 18, 2002
96
0
If the jetting and powervalve are correct what other mods make it pull harder in the middle and top.I live on the B.C. coast and don't have any time during the week to test jetting but I guess I could use kmac's jetting as a baseline.Kmac, do you know what the stock jetting is for up here?I've played with the main and pilot in a carb before but I don't know how to change the needle or where to count the position from[top or bottom?]
 

mx547

Ortho doc's wet dream
LIFETIME SPONSOR
Nov 24, 2000
4,787
102
this may be the first time in history that someone has said that a kx500 was too slow. :eek:
 

gwcrim

~SPONSOR~
Oct 3, 2002
1,881
0
Well lemme ask this:

When I bought my KX5, it had an FMF Burly pipe & ISDE silencer and an 11 oz. flywheel weight. Obviously, the bike has tons of low end. But it doesn't seem ungodly fast.

Would the add ons have a HUGE effect on the power band?
 

Camstyn

LIFETIME SPONSOR
Oct 3, 1999
2,247
2
No, mine was deceptive at times too.. What you have to do is ride a 125 or a 250 for half an hour on a MX track, then go back to your 500.. I scared the crap out of myself at least 10 times on the first lap after doing that.. Those corners come up FAST on a 500!
 

92cr

Member
May 18, 2002
96
0
I have no doubt that it's fast but I expected more especially mid and top.
I have no complaints about the low end power.My friend who has never ridden a kx 500 was not very impressed either.He had exactly the same opinion of the power.It simply doesn't pull cleanly mid to top.It may have been hard to gauge how fast I was going since I was riding in a wide open area with no other bikes around.Also my 92CR250 was much easier to pull the front wheel up in the top two gears.My gearing on the kx is 14/48.
 

Camstyn

LIFETIME SPONSOR
Oct 3, 1999
2,247
2
There is likely something wrong then, you'll probably find that one of the previous suggestions will be the cause.

I had a thicker head gasket, which makes a slight difference of less bottom, more top end.. But mine would make your eyes bleed at high RPM if you could stand the vibration! Any KX500 should have good top end power unless it has been modified.
 

RVL

Member
Mar 3, 2000
48
0
The Pro-Circuit pipe is the problem. I bought my 1989 KX500 used and it had a Pro-Circuit pipe on it. When I took it to Race Tech to get revalved, Paul Thede (the owner of Race Tech) asked me if I had the stock pipe. I said that I did. He said he would not bad mouth any competitor's product, but strongly suggested I try the stock pipe.
I did, and it scared the **** out of me. I loved the power, but the 1989 models had a much lighter flywheel than later 500s, and it was too crazy, even in the Mohave Desert. I wanted the huge power, so I added a flywheel weight to it, and lived happily ever after. I didn't even keep the Pro-Circuit pipe for a spare. It went right in the dumpster.
Later on that year, I spoke with Mich Payton, the owner of Pro-Circuit, about the pipe making the bike so slow. He made sort of a pained look, and gave an excuse that you needed his porting to make the pipe work.
If you really want that bike to fly, put a stock pipe on it. If you want even more power, run avgas in it. (I know usually it is bad stuff, but it made both my KX250 and KX 500 very frisky. My Hondas were the opposite. They got sluggish with avgas.) An engine tuner said the combustion chamber shapes of the Kawasakis made avgas work well.
 

gwcrim

~SPONSOR~
Oct 3, 2002
1,881
0
I think I might try a stock pipe, I already have the FWW. But what about the silencer? Is the Turbine Core ISDE too restrictive? Should I get a stock silencer as well?
 

kingfisher

Member
Apr 25, 2001
8
0
My 91' KX 500 flies. I have the stock pipe and silencer on it. I haven't ridden it since I bought my CRF450, but I miss the crazy speed every once in a while. The stock silencer is a cannon with a sparky on it, but there is virtually no restriction.
 

92cr

Member
May 18, 2002
96
0
I changed the pilot from a 60 to a 58 and moved the clip one notch to the top position [n82r].It made it run a little cleaner.before the plug was wet but now it's dry and dark with carbon deposits so I'm not sure if I should go leaner still maybe to a 55 pilot or a leaner needle.The powervalve was checked by the mechanic.It still doesn't rev as hard as I wanted but I went to Destry Abbott's website and watched some of his video clip's with kx500's and his bike sound's similar to mine so maybe that's just the way they run since I don't have another one to compare it to.The 98 I rode about a year ago ran very similar to mine as well and it had a fmf pipe and silencer.I don't want to go and buy a stock pipe and silencer since they supposedly crack alot easier.However the old factory KX500 that larocco and kiedrowski rode sure looked alot like stock.
 

Camstyn

LIFETIME SPONSOR
Oct 3, 1999
2,247
2
If you want an alternative to the stock pipe, apparently DG pipes do OEM replicas, with a nickel plated finish, for way cheaper than even any other aftermarket pipes.

I had a FMF Fatty pipe on mine for a while, it made the bike 'feel more powerful' but it took a little bit off of the very bottom and top ends to build more punch in the midrange.
 

92cr

Member
May 18, 2002
96
0
Well I got my powervalve fixed by my shop mechanic and I can tell you my bike is no longer slow.It pulls harder than any bike I've ever ridden.Thanks to all of you for your help.I won't be needing any pipe or other hopups for quite a while.It runs like a freakin striped ape.
 

nickx

Member
Dec 22, 2002
8
0
Where is the power valve and what does it do? What kind of maint. or problems does this bike have? Just traded my quad for a 2000 500. What is the top speed on this bike? Thanks for any help.
 

nephron

Dr. Feel Good
LIFETIME SPONSOR
Jun 15, 2001
2,552
0
Well I got my powervalve fixed by my shop mechanic and I can tell you my bike is no longer slow.It pulls harder than any bike I've ever ridden.Thanks to all of you for your help.I won't be needing any pipe or other hopups for quite a while.It runs like a freakin striped ape


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. :|
 

Hick

Member
Aug 15, 2000
224
0
Originally posted by nickx
Where is the power valve and what does it do? What kind of maint. or problems does this bike have? Just traded my quad for a 2000 500. What is the top speed on this bike? Thanks for any help.

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.
 

nickx

Member
Dec 22, 2002
8
0
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.
 

nickx

Member
Dec 22, 2002
8
0
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?
 


Top Bottom