Thinking of a Mild Supermoto Build

[Meeners]

Meeners 2008 KTM 250 sx Supermoto Build - Two Stroke Power

Yeah!!!!!










Current Modifications:

Engine, Drivetrain & Transmission, Cooling Mods
-- Stock 36mm Keihin PWK Carb Tuned by KRW Cycles
-- FMF Expansion Pipe & Spark Arrester
-- 520 116 Link EK O-Ring Chain
-- Motorex Top Speed 15w40 Synthetic Gear Oil
-- 13T & 14T Renthal Steel Sprocket, 42T KTM Rear Sprocket SM / 52T KTM Rear Sprocket Dirt

Air & Fuel Modifications:
-- Jetting; __ Pilot Jet, __ Main Jet
-- Running 40:1 Champion Water Pumper 2 - 2-Stroke Oil

Brakes, Wheels, & Suspension:
-- Dirt/Street Wheels: KTM 21"F & 18"R w/ __ Knobbies
-- Track Wheels: KTM/Behr 450 SMR 16.5"x3.5" & 17"x3.5 Fronts & 17"x5" Rear
-- Track Tires: 125/80/R420 F & 165/55/17 Metzeler K1 Racetec Slicks (120/70/17 Dunlop KR106 Slick on 17"F)
-- Big Brakes: Beringer FTE 4-pot Radial Caliper and Master Cylinder from 2006 KTM 560 SMR w/ Purte1 Radial Bracket Adapter
-- Small Brakes: Stock Brembo 2 Piston Front and Brembo Rear w/ F&R Stainless Lines & Motomaster 320mm Adaptor Bracket (Part no. 211012)
-- WP USD 48 mm Forks w/ _ Springs & WP PDS (Non-Linkage) MonoShock w/ Racetech SRSP 6326P15 Serviced by KRW Cycles for 208lb rider
-- Dominus/Motomaster 320mm Floating Rotor (Part no. 111043)
-- Scott's Steering Damper w/ _ Riser/Adaptor

Electronics
-- Ebay Hour Meter

Appearance & Cosmetics:
-- 10mm Rise 1-1/8 Fat Bars
-- Acerbis Copy Hand Guards
-- Moose Contour Inner Handguard Mounts
-- Skateboard Wheel Bar Sliders
-- KTM Axle Sliders
-- Ebay Peg Sliders


Planning/Brainstorming:

Stage 2: By Late Spring 2013
[_] ASV Brake and Clutch Bar Caps
[_] Look into Flywheel Change depending on if their are issues cornering
[_] KTM Supermoto Specific 14mm offset Billet Triple Clamp

Stage 3: Winter 2013?
[_] Total Loss Battery TRAIL TECH 8 cell battery pack or Batteries (Werker) Plus deep cycle
http://www.trailtech.net/040-BATT3.7.html
[_] Upgraded Plastics?

This is the old KTM 300 RIP



Action Pics!


Stock Information
Engine
Engine Type: 2-stroke
Displacement: 249 cc
Bore x Stroke: 66.4 mm x 72 mm
Engine Features: Single, reed valve, hydraulic clutch
Engine Cooling: Liquid
Carburetor: 36mm Keihin PWK
Transmission: 5 - speed

Chassis
Steering Rake: (Castor)26.5 degrees
Wheelbase: 58.1 in
Ground Clearance: 15.2 in
Seat Height: 37.8 in
Dry Weight: 210.3 pounds
Fuel Tank Capacity: 1.98 gallons

Suspension/Brakes
Forks: 48mm WP USD
Fork Travel: 11.8 in
Shock: WP, PDS No Linkage
Shock Travel: 13.2 in
Wheels: 21" Front & 19" Rear
Brakes: Brembo 2-Piston Caliper & DiskFront, Brembo Disk Rear


Helpful Links
www.ktmtalk.com
www.supermotojunkie.com
http://www.gearingcommander.com/
http://www.ktmpartfinder.com/
http://www.carbparts.com/keihin/need...hin_tuning.htm

380 motor can bolt in with small modification
Swap to sx 125 Triple Trees for Smaller Offset
Suspension Laden/Race Sag is 70-80mm for KTM SM Rear
Static Sag I'm going for 25-30% Adjust rear and match front

Rev limiters are pretty much for 4-strokes and that whole valve thing. Since you have no valves to float, you can rev it till it won't rev anymore. That's the joy of a 2-stroke. You may encounter a point where you loose all power and it feels kind of like a rev limiter. That was actually explained to me by a 2-stroke tuner/guru as a limitation of the pipe and head. I know I don't experience that with a low compression head, but do with a high compression head.

Being "on the pipe" is everything in a 2-stroke. I've found keeping up with the 4-strokes is often very difficult. We may share a similar top end but the bottom end and midrange is non-existent in comparison. They gain in such a major way on corner exit. If you're even the slightest bit off the pipe on corner exit, you loose out to those guys instantly. In some corners I'll end up going wide open before the apex, so by the time I'm at corner exit I'm on the pipe. Nothing will teach you throttle control like a 2-stroke! I take a great deal of pride when I race Supermini to even be able to keep up with some of those guys.

Anyhow, to the original topic question...just be mindful of your downshifts and run a rich bottom end (pilot jet). It may make your bottom end a little groggier, but if you're riding on the pipe correctly you won't even notice it.

I swapped from a 14:52 dirt gears to 14:46 gears for the local cart track. top speed is about 75-80mph.

I race on the stock brakes. I swapped the brake fluid to motul 800 dot 4 as it has the highest boiling point of any fluid available to me. I'd reccomend going with bigger rotor and caliper, but mine raced okay with the stock setup.

Other suggestions for you? If you plan to race that bike you are going to need to get the suspension revalved if you want to be competitive. if you are just riding for fun, then have at it. It's a blast to pass the 4-strokes on a smoker.

Oh, and try this jetting: 40pj, NAFH needle in the 3rd or 4th clip position and a 162 or 165 main. It'll rip your arms off on the road and allow you to run with the 450s. PArt of the reason I like this jetting is that the richer PJ keeps you from seizing the engine when you are blasting at 70 mph and then close the throttle and let it coast to a stop. If you run the stock 35PJ and do that you risk seizing the engine.

----------------------------
380 models with the 50mm extreme forks (98 and 99 models) have 17 mm axle diameter

380 models with 43 mm upside down forks (2000, 2001, 2002 models) have 20 mm axle diameter

if you use a 48mm fork of a newer model (the newer the better ) then its 26mm axle diameter. we use such a fork (and we also have to use other triple clamps).

[BEARDLESS]

I am very seriously considering building a budget moto build (I know budget and supermoto shouldn't be in the same sentence but hear me out)

??? Buy one already built!! I built a "budget" DR200 and beat the shit out of it. Ended up selling it for $800 I think. I ran into a lot of stupid problems trying to be cheap. Cheap rims/tires are the main problem. But I also say GO FOR IT! because I loved by tarded ass little 200 and wished I never sold it... Might just be me but I think you are going to have to do quite a bit of suspension work if you wanna convert a dual sport too.

[Katifer]

Based on what Ive heard, buying one already built saves time and money rather than building your own. But you like to tinker, so who am I to stop you? Im likely going to be right there with you on the kart tracks. It really was a lot of fun. However money-wise I cant afford to keep the two-fiddy (NO MOAR LOANS). I know Jared really wants a motard. We will have to work something out in the spring!

[Meeners]

I am very seriously considering building a budget moto build (I know budget and supermoto shouldn't be in the same sentence but hear me out)

??? Buy one already built!! I built a "budget" DR200 and beat the shit out of it. Ended up selling it for $800 I think. I ran into a lot of stupid problems trying to be cheap. Cheap rims/tires are the main problem. But I also say GO FOR IT! because I loved by tarded ass little 200 and wished I never sold it... Might just be me but I think you are going to have to do quite a bit of suspension work if you wanna convert a dual sport too.

I want to see pics of this!!! I think I'll have to spend money on the wheels and tires just from exploring the Excel options... or maybe buy them used from the super moto forum or something. Can you elaborate on the suspension ordeal? I'm open ears.

If I could find one complete and used and broken for $1500 I would def consider it (everything i've bought used I usually have to wrench on to get it to work anyway). Swapping a motor is DEFINITELY something I can do. If I build it the only initial cost I'm worried about is the actual cost of the bike... the build costs don't scare me much as I'm not afraid to take my time (2 yrs if it needs to be). Shit, a $5k build over 2 years would only be spending (or saving, in my case) $100 dollars a month.

Based on what Ive heard, buying one already built saves time and money rather than building your own. But you like to tinker, so who am I to stop you? Im likely going to be right there with you on the kart tracks. It really was a lot of fun. However money-wise I cant afford to keep the two-fiddy (NO MOAR LOANS). I know Jared really wants a motard. We will have to work something out in the spring!

Yeah... everyone always tells me that all the time. They've also told me that with cars too but it's always fun to break the mold and be different. I'm willing to bet this is the same ordeal.

I hear you on this one girl... Times is rough for you, me, and a few others. We will make it! In the mean time, I will continue to support and be an attendant at the track days if possible.

If I can get on the ball and do this, you know for sure you guys are more than entitled to rock my shit... The other reason I am interested in building this damn thing is if it goes down I won't give a damn! Yaaaaaa! I need to find a blown dirt bike or something... Shit, maybe we can help each other.

[bassJAM]

I've been thinking about a tard build once I start working full time again. I'm not sure what I'd start with but and XR400 keeps popping up in my mind. It's a simple reliable engine that's easy to get power out of. I'm not really a fan of the modern off-road four-strokes and their rebuild schedules.

[Cowboy]

Man whats with the huge motard craze now a days? Seems like everyone I talk to wants to get one. The dirt is where its at if you wanna go cheap

[RRP]

Not to jump on the bandwagon, but if you want to go budget on a motard ---for $4-5000K you can pick up a tricked out Husky 450 or 510 with all the toys on it already. Now if you want a project as well...then by all means build one. Good luck...

[dobr]

The best bike for the Kart track was the little WRX250 that was there. I think most of the folks there would have agreed. My Husky was way too much for that track.

[Meeners]

I've been thinking about a tard build once I start working full time again. I'm not sure what I'd start with but and XR400 keeps popping up in my mind. It's a simple reliable engine that's easy to get power out of. I'm not really a fan of the modern off-road four-strokes and their rebuild schedules.

I wonder what a two stroke would do... I'd like to build one... I can't think of really any drawbacks unless i tried to take it on backroads, which I don't see doing much if I have a street bike already. are the older xr400's 2 stroke or are they just an older 4 stroke?

Man whats with the huge motard craze now a days? Seems like everyone I talk to wants to get one. The dirt is where its at if you wanna go cheap

I don't know about the craze, all I know is that what I see looks fun... and seems more feasible for me with my situation. I can't justify building a race bike if I only go like 2 to 3 times a year (which is all I feel I would be able to afford)... so this is the next step down. Poor Man's Track Day if you will...

Not to jump on the bandwagon, but if you want to go budget on a motard ---for $4-5000K you can pick up a tricked out Husky 450 or 510 with all the toys on it already. Now if you want a project as well...then by all means build one. Good luck...

That actually sounds awesome... but, that's not within my budget... I've built a 350 hp drag car for less than that... but that's neither here nor there since bikes are a different breed. You would shit yourself if you knew how much I paid for my cars/bikes. Just looking to put together, or build something I can thrash around and not be afraid of going down with.

The best bike for the Kart track was the little WRX250 that was there. I think most of the folks there would have agreed. My Husky was way too much for that track.

Can you give me a synopsis on why the WR was the best? I'd like to hear...

[dobr]

The 250 had a much more usable power band on the small track like that. I never got out of third gear. I also could never slam the throttle wide open for fear of not being able to stop at the end of straights. Add the light weight of the wrx250 and you had a perfect little track weapon for that type of riding (Kart track). it is a very purpose built machine, and that is its perfect purpose. Now on a regular road track I would take my 450 all day long.