Author Topic: KX500 AF Running like a 200  (Read 26745 times)

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Offline Polar-Bus

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Re: KX500 AF Running like a 200
« Reply #15 on: May 01, 2013, 12:03:08 AM »
How does the engine sound when accelerating ? Does it sound deep burbly rich ? is the power flattening out in the midrange ? Your jetting seems to be in the ballpark of what most of us are running. Could be the dents in the pipe, but i've seen some nasty dents in a pipe and the engine will still run great..  Did your engine ever run 100% ?

FYI, I had the same exact engine symptoms right after doing a top end in my K5, long story short, I  mis-timed the KIPS gears assembling my new top end.
01' KX500
'84 GPz1100
'87 GSX-R  750
'06 HD Fatboy
'73 Kawi H1
'03 CRG KX500 Shifter kart

Offline RKPerformance

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Re: KX500 AF Running like a 200
« Reply #16 on: May 01, 2013, 12:20:04 AM »
I just got the bike so no it has never run "right"  It does sound really burbly and smokes pretty good.  The kips seems to be working by hand and opening and closing right.  It was amazing how s**tty it would run when i put a 168 main  in it.  A 125 would run past me easily.  Think i should try a 160 main if nothing else seems to be off with the bike?

Offline RKPerformance

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Re: KX500 AF Running like a 200
« Reply #17 on: May 01, 2013, 02:44:50 AM »
I just measured the carb and it looks like it is a 40mm bored.  Is it possible that the tight bend and pinch in the neck of the pipe is restricting exhaust so much that it isnt allowing the valves to open all the way?  The pipe is filled with black slobber too.

Offline lsampson

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Re: KX500 AF Running like a 200
« Reply #18 on: May 01, 2013, 02:52:52 AM »
The exhaust valves are regulated by a governor as I understand it, not exhaust pressure, so the kink in the pipe shouldn't affect the valve operation. However, if the pipe is kinked, it does increase backpressure which isn't good as it can greatly affect performance. You want some backpressure to keep intake gasses in the cylinder (rather than the exhaust), but not so much that it pushes intake gas back out of the cylinder.
« Last Edit: May 01, 2013, 02:56:15 AM by lsampson »
When in doubt, throttle out!

Offline Polar-Bus

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Re: KX500 AF Running like a 200
« Reply #19 on: May 01, 2013, 05:20:33 AM »
Idealy if you could bolt on a stock k5 pipe and try the bike that would approve or dissaprove speculations about the pipe being kinked and restricted..
01' KX500
'84 GPz1100
'87 GSX-R  750
'06 HD Fatboy
'73 Kawi H1
'03 CRG KX500 Shifter kart

Offline RKPerformance

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Re: KX500 AF Running like a 200
« Reply #20 on: May 01, 2013, 01:49:00 PM »
More Info>

The pipe on it is a FMF Fatty # 160797  Y-28
Doing some research this it seems to fit yz250s from 93-4 & wr250s from 94-97

The silencer on it is a FMF Turbine sst # 020406 TDS-3
This seems to be for a 99-02 KX250.  It is def smaller diameter than a 500 silencer.

Is this exhaust setup a possible cause to my lack of power>>????

Offline sandblaster

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Re: KX500 AF Running like a 200
« Reply #21 on: May 01, 2013, 02:02:14 PM »
Yep, I'd get it changed and go from there.
Where abouts are you?
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline RKPerformance

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Re: KX500 AF Running like a 200
« Reply #22 on: May 01, 2013, 02:05:09 PM »
Michigan.

Where can i get a pipe and silencer to work on this baby?

Offline sandblaster

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Re: KX500 AF Running like a 200
« Reply #23 on: May 01, 2013, 02:12:39 PM »
If you were local I'd have you come to the shop and see if the Service Honda pipe would work...
Your a bit out of the neighborhood... Oregon  :lol:
You might want to call Service Honda.
But, why not post some pics of your bike as that may elicit more help.
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline RKPerformance

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Re: KX500 AF Running like a 200
« Reply #24 on: May 01, 2013, 02:28:21 PM »
Would you be interested in selling that pipe?  Im sure I could make it work with a little tweek.  I really dont feel like fabbing one up from another pipe and ball peeining it all up!  I will get some pics of the bike up soon

Offline sandblaster

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Re: KX500 AF Running like a 200
« Reply #25 on: May 01, 2013, 02:29:14 PM »
No way Ray  :-D
Call Service Honda and tell them what your doing and beg...  :-o
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline RKPerformance

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Re: KX500 AF Running like a 200
« Reply #26 on: May 01, 2013, 02:37:39 PM »
Ill buzz them up tomorrow and see if i cant get a pipe and silencer from them.  They are in stock cuz i called them today and the lady said they had em on hand so hopefully they will sell one!!!

Offline Goat

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Re: KX500 AF Running like a 200
« Reply #27 on: May 01, 2013, 03:43:05 PM »
Where at in Michigan. I'm over in Bay City area.
It's hard to keep a drivers license riding a 2 stroke dirt bike on the street.  If you drive within the law they are VERY boring.

Offline motopunk

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Re: KX500 AF Running like a 200
« Reply #28 on: May 01, 2013, 06:09:06 PM »
More Info>

The pipe on it is a FMF Fatty # 160797  Y-28
Doing some research this it seems to fit yz250s from 93-4 & wr250s from 94-97

The silencer on it is a FMF Turbine sst # 020406 TDS-3
This seems to be for a 99-02 KX250.  It is def smaller diameter than a 500 silencer.

Is this exhaust setup a possible cause to my lack of power>>????

oh holy s**t   :-o:roll:... with this pipe and silencer of 250 it can not function properly as well.the 250 expansions chamber and also the diameter of the tube in the 250 muffler is too small for the 500 engine. i mean this exhaust is a performance killer. :evil:

 i use a modifyed cr500 stock pipe on my conversion. and it make my conversion a little bit oem-look  8-). and thats what kawasaki already a long time ago should build ... :wink:

 but you can use the body of the 250 muffler with the inner tube of a kx500 muffler and it bolts on right to the 250 subframe :-)
big 2 stroke bikes are weapons for real men, who don´t fear death or devil. ;O)
´83 kx250, ´87 kx250 (with 360 big bore), 87 kx500, ´93 kx500 sfc

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Offline Polar-Bus

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Re: KX500 AF Running like a 200
« Reply #29 on: May 02, 2013, 12:12:02 AM »
Jeez, sounds like the p/o did a hillbilly hack conversion. So not only do you have a 250cc pipe on a 500cc, you also have a kinked, restricted 250cc pipe on a 500. Sounds to me like you definitely found your issue..
01' KX500
'84 GPz1100
'87 GSX-R  750
'06 HD Fatboy
'73 Kawi H1
'03 CRG KX500 Shifter kart