KX500 SUPERMOTO TIPS?

[tha.steev.oh]

First timer to this site but excited as hell to get started.

I am looking to spend the winter building a 2000 KX500 supermoto that'll take the thumpers' lunch money at the track next year. I'm new to the 500 but not new to 2-smokes. Beyond freshening up the engine, the list of mods I am planning are:
- 17" supermoto rims/tires
- 4-piston Brembo front brake kit (including master cylinder, 320mm rotor, and steel braided lines)
- reed spacer & V-Force
- KIPS bolt mod
- piston window mod
- bigger carb (41-44mm?)  * What would be the trade-offs to a bigger bore?? *
- possibly porting??
- lighten the flywheel
- FMF Gnarly pipe & Powercore silencer
- custom pipe/skidplate "cage" for asphalt protection

Can anyone see an area for improvement? I've checked many forums and you guys are far and away the best resource on the web. Looking forward to your feedback.

Thanks,
Steve

[KX500freak]

yea you have it all figured out ,nice work ,
i could only suggest you for a suspension revalve and adjust for sm,
for all sm projects check the sm section
for the 12 mm master ,my experience is that you need to squeeze to hard ,better stay stock first with a 4cal. only
my sm,s runs stock carbs but jetted and one has boyesen reeds with a big pipe
i also did a custom pipe/pump protector on my racer
succes !

[Larry Wiechman]

I'd vote for a heavier flywheel. You'll have a power advantage, but won't be able to hook-up as good (or as early) as the thumpers. Will the tracks you run have a dirt section?

[tha.steev.oh]

- Will the stock master cylinder be strong enough to squeeze big 4-piston brakes? I had hoped it would to save $ but didn't want to complete everything and have mushy stoppers.
- There is no offroad section... yet .The local street course is tight with one long straight away (1/2 mile??) so I'm confused on gearing. Need power down low for the twisties but don't wanna be eaten on the straight. Couldn't find the gear / speed calculator in the search for some reason.
- I've got a long motocross history but never ever had to touch my flywheel. I thought lightening it was going to smooth out the power delivery off the bottom...

[KX500freak]

well ,i had a 12 ,even 14 mm pump and it was to big for my tokiko 636 4pistoncal.
i went back to 11 mm stock and then i had real squeezing feeling in my fingers
buddys run also stock
pumps but with brembo or motomaster cal.

for track gearing ,im running 14/42 on my racer ,does the job fine.also 1/2 mile straights
and tiny twisters and chicanes

no single 4 stroke ever gets past it exit cornering and acceleration pick up

and a lightened flywheel gives the crank less inertia,
so when you twist the throttle the motor revs out even quicker


 

[tha.steev.oh]

Thanks KX500freak!

- I'm brand-new to this (the bike and the forum) so i appreciate any help out there.
- I'm doing this bike on a budget (aren't we all?) so using the stocker master cylinder will free up some $ for something else.
- That is the 2nd time I've heard 14/42 gearing for 'tarding so I'll definitely start there. Do you know approx what your top speed is?
- So... Now that I know I shouldn't be shaving the flywheel, how much weight should I add to it to smooth out the power delivery for a street course?

steev.oh

[muleman]

Nice i just built one for street use. good luck

[KX500freak]

Thanks KX500freak!

- I'm brand-new to this (the bike and the forum) so i appreciate any help out there.
- I'm doing this bike on a budget (aren't we all?) so using the stocker master cylinder will free upsome $ for something else.

yes indeed!

- That is the 2nd time I've heard 14/42 gearing for 'tarding so I'll definitely start there. Do you know approx what your top speed is?

its imo the perfect gearing for 56 sec/round tracks,and it tops out @ guess round 80mph more the less ? i have this vid of the racer tho ,it is only 2nd and 3rd gear here http://www.youtube.com/watch?v=TQsqciYJN6c

- So... Now that I know I shouldn't be shaving the flywheel, how much weight should I add to it to smooth out the power delivery for a street course?

i have my racer stockflywheelweight,its good,quick response,but my streetk5 has a big lightcoil,this gives more "swing" to the crank ,but for racin you should not want to add weight,imho,so best keep it like it is i think ,also the cheapest  im budget too 

steev.oh

[tha.steev.oh]

- Yeah, the local track is about a minute flat so we're on the same page.
- I'm gonna try the stock flywheel 1st and then decide from there.

- Anyone try a bigger carb? I used a 38mm (up from 36mm) on my 125 back in the day and it made a big difference on top...

[KX500freak]

my k5 ,s all run stock carbs ,but jetted and with aftermarket pipes,so can, t help you here

[PowerFiend]

well ,i had a 12 ,even 14 mm pump and it was to big for my tokiko 636 4pistoncal.
i went back to 11 mm stock and then i had real squeezing feeling in my fingers
buddys run also stock
pumps but with brembo or motomaster cal.

for track gearing ,im running 14/42 on my racer ,does the job fine.also 1/2 mile straights
and tiny twisters and chicanes

no single 4 stroke ever gets past it exit cornering and acceleration pick up

and a lightened flywheel gives the crank less inertia,
so when you twist the throttle the motor revs out even quicker


 

Which Brembo are you talking about? With the 4pad 4piston a 13mm brembo or TRX450r quad master works best. A 12mm is like one finger girl strength stoppies, and you have no feel in the dirt. Of the two, I like the TRX master, since it has a dirt sized lever and not the large road lever like the brembo.

Stock dirt master or 12mm brembo master works well with the motomaster.

I run the TRX master with the QTMI 4pad 4piston cast brembo setup on my XR650r street SM. My KTM450SMR has the stock setup replaced with another 4p4p brembo with a 13mm brembo master(That was on my CR500). The 12mm that I tried and hated ended up on my old and sold 02 WR426F street SM(450F plastics), combined with a motomaster.



More flywheel would probably be good for the 500. I never ran my KX in supermoto trim, but the CR500 didn't have any trouble with anything smaller than 560's in the straights. The hardest part is keeping corner speed and getting good drive out of the corners, and also trying to keep some kind of hookup in the dirt. The 500 was easy to spin up in the dirt = bad.

[tha.steev.oh]

- Awesome! I'll look into your master cylinder tips.
- If Wardy's running more flywheel weight, then it must be the hot set-up for SMR. How much would you suggest for flywheel weight? Guys on here are mentioning Steahly a lot - would you recommend them or are there any other comparable companies for SMR applications? (FYI - I'm gonna be running 14/42 gearing and expecting 65-68rwhp).

- I'm gunning for my buddy's 2008 Aprilia SXV550...  ... It's a great bike and know I've got my hands full but it'd be awesome to roast him on an "old sleeper". I can tell he's already a little nervous  .

Steev-oh

[kx5rider]

For handling I really like my offset tripple clamps....only thing I don't like about em is it's solid mount bar setup....as if the 500 hundie didn't vibrate enough I also just finally found a set of pro circuit dogbones, they are fairly cheap and are suppose to help it corner a bit better, can't wait to try those out.
I just had the rear shock gone through and race tech guts put in before my last session and that helped a bunch. I couldn't slow down the rebound enough on the old worn setup and it would rebound way to fast up causing the front to dive. Now I just need to put the race tech and new spring setup in the fork and it should really be happy.
I'm running a 320 ebc rotor and the rest of the brake setup is stock with a relocator bracket and good motul fluid, it works but I get some serious arm pump I've got a nice set of steel braided lines to put on and they should help a ton. On the rear it's all stock with a wave rotor and I've actually boiled the fluid on a tiny tight kidney bean track...never had issue on a standard size cart track though.
Motor wise I got a fmf gnarly pipe/silencer, boyesen rad reed setup and the cylinder has been sleeved and punched to a 520(ish). The motor pulls like mad and slides very nice on exits. I have a flywheel weight but found with the pipe/reed setup it's more than enough snort off the bottom...I'm afraid the weight would kill the top end pull
I love yanking the big 4 pops in the straights and the 500 is a holeshot machine!!!!! The only funky thing I found with the big 2 stroke is how the engine surges... or pulses I guess mid corner. When a 4 stroke guy gets on it I try an explain on decel it will go ding.....ding and on the 3rd ding be ready for a lurch. They look at my 2 stroke babble crazy till they come back in. It can catch a guy off guard

[DoldGuy]

KX5,
What clamp setup are you using (how much less offset)? Give us some feedback on the Pros (better frontend bite?) & Cons (headshake?) I am very interested in your input on these & your opinion on the dog bones (I use them & like them).

Thanks in Advance
DoldGuy

[kx5rider]

The triples are made by Emig Racing. It seemed to stiffen up the front end for the pavement stuff a bit, especially on the fast sweeping stuff. The bike also seems to steer in quicker now as well but I also did drop the trips on the fork just a hair because the track we ran that weekend was pretty tight. It dances a little on the straights but nothing bad, just seems to hold the corner a little better now and that's where I lose ground to the new 4 strokes....it definately ain't in the straights!!!!!!
It feels like it pulled everything back twords me but i'm not sure on how much of an offset they are vs. stock, I got em used on e-bay and the seller didn't have any idea.
Here is a my stock setup

Heres the Emigs.....just a little difference