dyno charts and pipes

[kawdude]

Is it normal for all KX5's to begin to fall off the peak power at 7K rpm.  Is this the slow reving aspect of the 500cc motor?

[delusionised]

normal for the stocker, check out the dyno graph.

[doordie]

delusionised!

Yeah it?s some kind of brutal!
first gear: wrapp  
second: OO-Yeah  
third: what the F...
fourth: Mama plz help me  
fifth: oneway ticket too the moon  

[doordie]

demographic!

I will tell you some mods ,but this is a special bike for only one thing, to produce much HP at high speed on ice,it will not suit for mx or trail.

Ported to very high portimes.(Roadrace-duration).
Iron sleevecylinder.(Easier to adjust ports).
Reshaped head.
Ovalbored carb.
KN-filter.
Reshaped reed with coalfibreflaps.
Modified Kips.(Diffrent springpreload).
Modified exhaustport.
SKF C3 bearings(For high rpm).
P.C desert pipe/SPES pipe or shorten standard pipe.
Trued crank (Filled holes).
Ignition retarded.
Lighter flywheel.
This is the most of the mods  

[demographic]

demographic!

I will tell you some mods ,but this is a special bike for only one thing, to produce much HP at high speed on ice,it will not suit for mx or trail.

Ported to very high portimes.(Roadrace-duration).
Iron sleevecylinder.(Easier to adjust ports).
Reshaped head.
Ovalbored carb.
KN-filter.
Reshaped reed with coalfibreflaps.
Modified Kips.(Diffrent springpreload).
Modified exhaustport.
SKF C3 bearings(For high rpm).
P.C desert pipe/SPES pipe or shorten standard pipe.
Trued crank (Filled holes).
Ignition retarded.
Lighter flywheel.
This is the most of the mods  

Thanks for that.

Mine gets used on the road as it's in Supermoto trim at the moment so some of those mods might be worth knowing about.

I notice you say the head has been re-shaped, did you lower compression to provide more over-rev? as I have heard of people putting two head gaskets in to do this.

I assume that coalfibreflaps means carbon fibre reads?

When you say different spring preload for the KIPS did you add or remove washers to do this?

Perhaps used a different method?

Holes filled in crank, Did you also get the crank welded as I have seen an article in a dirtbike mag that sugested doing this to stop the crank slipping out of true (the article was about 91 KX 125s though)

I might just have a bit of a play about with the ignition also.

You have got me thinking now

[doordie]

demographic !!
Okey here is some more "secret" info.
Reshaped (a copy of a kx80 aircooled 1980 modell ,with offset sparkplug).
Tighten squish-clerance to 1,3mm(avoids detonation) and another squish-angle then standard,another squishband, +5%hp in midrange and no detonation at long straights.
You can?t put two gasket and guess,you have to measure compression ratio and the squishclearance.
Yes,carbonfibre reeds,sorry.
The KIPS is under construktion,more info later.
No welded crank,think this is not a problem ,but i will considered it.
Crankholes filled to raise crankcasevolume and this allow shorter transferporttimes.
I WANT programmable ignition,but too expensive.
When you "play" with the standard ignition, don`t overadvance it,you can ruin the engine in a second.

[demographic]

All good stuff

I don't think I will go the whole hog but some of those mods might be on the cards.

I am glad to hear any info on tuning KXs cos even if I don't do it now I might eventually do it

[delusionised]

i just added v-force reeds and an fmf fatty in one shot, now i am scared in the tight stuff. Wide open, my eyes bleed. I love this bike

[gowen]

Hey Doordie,

What modifications have you done to your bike to get that kind of power?

I'll second that..

[gowen]

demographic!

I will tell you some mods ,but this is a special bike for only one thing, to produce much HP at high speed on ice,it will not suit for mx or trail.

Ported to very high portimes.(Roadrace-duration).
Iron sleevecylinder.(Easier to adjust ports).
Reshaped head.
Ovalbored carb.
KN-filter.
Reshaped reed with coalfibreflaps.
Modified Kips.(Diffrent springpreload).
Modified exhaustport.
SKF C3 bearings(For high rpm).
P.C desert pipe/SPES pipe or shorten standard pipe.
Trued crank (Filled holes).
Ignition retarded.
Lighter flywheel.
This is the most of the mods  

Considering, I ride 95% in the top-end, I think I'd like to try a few of these modifications. Doordie, what did you use to lighten the flywheel?

I was thinking, I have an old '89 kx125 that is rusted and dead laying in my trash pile of bikes in the back, I decided to open the flywheel cover and remove the flywheel/stator/pulser/cdi/ignition. The kx125 flywheel is maybe a third the wieght of the kx500 flywheel, is this too extreme? I know I would need to use the pulser/stator/plate/cdi to the kx and maybe purchase an electronic ignition to advance/retard the timing to suit the k5. Just curious if this would kill all power to the kx500?

[mikesmith]

If I remember right the aftermarket PVL ignition comes with a lighter flywheel and is made for top end, if you want to spend the money on it.

[gowen]

Who sells PVL ignitions? I've honestly never heard of them. But sounds like a plan.

[mikesmith]

I never have checked it out my self because from what I hear a PVL is all top end (not what I want) but try www.pentonimports.com.If they dont have it they could tell you where to get one.I know a few years back a guy on the old KX web site had one he was trying to sell or trade for a stock KX ignition.

[mikesmith]

Well I just tried the link and it didnt work,so  heres the info, Penton Imports Co. 1115 Milian Ave,Amherst Ohio 44001 or phone 440-988-4474 and the Fax:440-988-4476,hope that helps.

[kawdude]

Try this...

http://www.pentonimports.com

The link above includes the ".If" in the URL...