Kx500 snowbike more power!

[Apetty]

Well to start I have a 1993 kx500 with a 16 timbersled LT. this was my first season on the snowbike and loved it! My kx5 has more than enough power for me on dirt, but it takes a lot of power to turn that track, not to mention the elevation loss. For snowbike standards only the 450 turbo guys have more than me. So far I have a fresh top end, Lectron carb, boyesen Rad valve, and an fmf gnarly pipe. Really I don't know how much power I want or how far I want to go, but I want to consider all options though. I've considered a lot of different possibilities like big bore, turbo!!!, nitrous shot, porting, cylinder head mods, ignition mods. Really I'm wondering if anyone has any experience with any of these or maybe some I didn't think of. The turbo idea I think would be the most interesting. Would be really tough to do but I know guys who have 2 stroke snowmobile turbos. Really though I want the most power I can get and still be fairly reliable. There must be some one out there who has contemplated pushing the limits with a kx5. I eagerly await your responses. And thank you in Advance.

[sandblaster]

Regardless of which way you choose to go remember this...
If your going to breathe more power into your K5 you need to have a solid bottom end.
More power generally means less engine life.
So everything is a trade off...
Start off building your bottom end with all new bearings, Wossner rod, balance it.
Mic your shift forks and make sure they are in spec.
Inspect your gears carefully.
Consider having the dogs back cut.
On your top end, lifting the cylinder, decking it, porting it, having the head cut, bumping the compression, and running a blend of VP will get you a respectable amount of power.
A big bore is nice especially when you lift the cylinder but can get a bit spendy depending on how far you go.
If you decide that you want help with any of this, give Jason Tanner at JT Engine works a call   541-653-5334
He is part of the team that built Sean Colliers latest K5 and is currently building him a new engine to freshen up his old K5.
You can read about it here:
http://www.oem-cycle.com/forum/viewtopic.php?f=41&t=1170

[big green]

I certainly won't argue with anything sandblaster said and I am sure you would get a quality build from jt engine works. I went with Tom Morgan for my build and have been more than satisfied with the build and the support after the build. If you are not farmilar with Tom he is a legend in the Kawasaki community and was also Jeff Ward and Mike Larocco's mechanic among others and knows his way around championship winning KX 500's as well as anyone.Tom has always been willing to take a phone call or answer an email promptly whenever I have had a question. Crazy, usable power! contact him at Tom Morgan Racing at tmm_tmr@yahoo.com or 949 421-7112.

[Apetty]

Yeah it's probably a good idea before I try to push more power out to make sure of the bottom end. Especially because I've never been through the tranny to check things. I thought I heard somewhere that third gear likes to go out on the kx5. Anyways is there any reason to use the wossner rod over a different one? Right now I actually have a wiseco piston in it and started reading here a lot of guys haven't had good success with them which is a little scary. Otherwise do you have a lot of Experiance with JT engine works? I read the build which was pretty cool. If there is probably one thing I want to avoid is having to run straight race gas. But I will probably give him a call, not looking to make a commitment yet on anything but just seeing what options are out there.

[sandblaster]

3rd gear is a weak spot.
It's not that the gear is inferior to other bikes... its that the K5 is a animal and 3rd gear is really the first gear that you can hook up and get that power to the ground. While you are in the trans, replace all the snap rings.... Also, measure your shift forks, many are way out of spec. You can't get new ones but you can get yours repaired.
The Wossner is a superior quality rod.
If you are going to mod the K5 better seriously consider it.
If your running stock, the stock rod will work great.
Wiseco pistons went through a long period of low quality.
However, if yours has been up and running for a while then no worries.
Jason at JT Engine Works, operates from my shop 
I can tell you this, there are few and far between builders out there that have the eye for detail, the K5 knowledge, and the ability to put it all together in the way that Jason does at any price.
But I say, shop and compare.
Get a quote from all parties..
Get it in writing what they plan on replacing and with what.
Often it's what is not included on a quote that will get you....

[big green]

3rd gear is a weak spot.
It's not that the gear is inferior to other bikes... its that the K5 is a animal and 3rd gear is really the first gear that you can hook up and get that power to the ground. While you are in the trans, replace all the snap rings.... Also, measure your shift forks, many are way out of spec. You can't get new ones but you can get yours repaired.
The Wossner is a superior quality rod.
If you are going to mod the K5 better seriously consider it.
If your running stock, the stock rod will work great.
Wiseco pistons went through a long period of low quality.
However, if yours has been up and running for a while then no worries.
Jason at JT Engine Works, operates from my shop 
I can tell you this, there are few and far between builders out there that have the eye for detail, the K5 knowledge, and the ability to put it all together in the way that Jason does at any price.
But I say, shop and compare.
Get a quote from all parties..
Get it in writing what they plan on replacing and with what.
Often it's what is not included on a quote that will get you....

Well said!

[Apetty]

Minor update: I haven't called Jason yet, but I do plan to hopefully in the next week or so. But I ended up buying a blown up 06 Kx250f for 300. I keep kicking around the idea of a af conversion. My original plan was not to do an AF conversion, but for 300 bucks I figured I could keep it around for awhile and maybe I'll get motivated enough and I could almost sell the cases and make my money back for that. But anyways I've been trying to research how to do this as much as I can but have a couple questions. Does the swing arm pivot bolt line up? Also does anyone make some kind of a kit or parts you could buy that might get you half the way there or so? Anyways if I get serious I'll start a new thread about this in the AF section. Just debating if it is worth my time because the snow is coming fast!!!

[1901306708]

So i've been through the last years or so on a service kawi kx5 snowbike. i have at my disposal a pipe builder with a dyno, and a really good cylinder guy.

Stock, the cylinder will simply not flow any more air. you can't make much more torque and you certainly can't make it rev. You can fool around with reeds, pipes, heads etc and make the cylinder look pretty. this will get you to about 62hp at most.

now if you know a good cylinder guy, you can make a bunch more power. but you need to make drastic changes. but then the stock pipes wont work very well. you need a real pipe, bigger carb, open up the reed boot as wide as you can etc etc and things start paying off. mine is around 80 horse @ 8200rpm with tq just under 50 for quite a long rpm range.

For snowbike application
-you need to heat the carb with coolant. you probably know that already.
-also the piston clearance is too tight for snow application. couple reasons...rapid heat/cooling when the cylinder is packed with snow, and longer periods of high load.
-thermostats are a good idea but take some fiddling.
-the pvl ignition is good and gives you 80w of power to run a light. stock, mine made the most power at 26 degrees. most guys say thats too much. most guys dont have a dyno. use good fuel though. the pvl ignition will also fry and the slightest sign of water. learned this lesson many times. once its been wet, the next time it gets hot it will fail 100% of the time. you need to silicone it up real good for it not to leak..like unbelievably well.  if you fix the head to something reasonable, then 20 degrees is about where you want to be.

if you want anything more specific let me know. tks

[Apetty]

Update: finally some headway. Been talking with Jason from JT Engine works and I'm going to send my engine off to him! From talking with him I got the impression that he has forgot more about the kx500 then I'll ever know. Still not sure exactly what we're going to do to it but for sure porting, big bore, crank rebuild balance, transmission gone through, new clutch basket and clutch etc. very excited to see how this turns out. In response to the last reply it is always awesome to hear from another kx5 snowbiker. I was thinking of going with the new electric start from pantera which comes with the pvl ignition but from your comments I'm alittle afraid. I don't want a finicky system. The last thing I want to do is get stranded in the back country. Have you had many problems with your pvl or what do you think of the e start? I'm running a Lectron carb with an avid carb heater setup with thermostat which worked great last year. I've heard a tunnel cooler works better but so far no problem for me. I'm also running a gnarly pipe does it pay to get a custom one?

[sandblaster]

With what Jason and I have discussed that he is thinking on your build, YES... a bigger pipe will be required to get the performance you need.
Also, what size is the carb?

[Apetty]

40mm Lectron

[1901306708]

Update: finally some headway. Been talking with Jason from JT Engine works and I'm going to send my engine off to him! From talking with him I got the impression that he has forgot more about the kx500 then I'll ever know. Still not sure exactly what we're going to do to it but for sure porting, big bore, crank rebuild balance, transmission gone through, new clutch basket and clutch etc. very excited to see how this turns out. In response to the last reply it is always awesome to hear from another kx5 snowbiker. I was thinking of going with the new electric start from pantera which comes with the pvl ignition but from your comments I'm alittle afraid. I don't want a finicky system. The last thing I want to do is get stranded in the back country. Have you had many problems with your pvl or what do you think of the e start? I'm running a Lectron carb with an avid carb heater setup with thermostat which worked great last year. I've heard a tunnel cooler works better but so far no problem for me. I'm also running a gnarly pipe does it pay to get a custom one?

I have had mine die twice on me. no notice, just boom no spark. almost needed a chopper once. was not fun. i have a spare one wired up ready to go at the truck now, so worst case i can double out and come back and do the swap so i wouldn't need a chopper. its all related to coolant temp. it must be when the water inside the stator turns to steam or something. both times i was working it hard and it was warm. i would say if you had a way to keep your water temp below 170F all the time you would be pretty safe. Yeti makes a nice cooler. i'm going to try that this year.

e start would be great but i see drawbacks. first i think they use a keyway. that means you cant adjust your timing anymore. thats an issue. there are big losses and gains with timing changes once you start playing around with the cylinder.

in our testing the 44 lectron makes 2hp on a stock motor. roughly double that on something modified quite alot. kevin does a good job.

there are gains with pipes. in stock form, its really all about making peak torque over a larger rpm range.

to me, a larger bore doesn't make much sense and the last thing i would focus on. the bore is already too large and the cylinder cant fill it properly. now you add in elevation and it gets worse.

those are my thoughts man. hope they are half helpfull.