DFW to Ouray 2 Stroke

[shirazk]

Thinking of taking my 250 ktm to ouray.
It barely runs well with me screwing with it here, and i bet it will be crap if it take it to engineer pass as is.
Question is do you have to rejet bikes for altitude or can they be adjusted?
Does anyone know of an idiots guide to carb tuning?

 

[Kid2watch]

Buy a JD Jet Kit for your respective model and jet per the instructions for altitude.

 

[sanderjavant]

For me, on a KTM 300 it was a Lectron, to be able to vary elevation as much 4-5k on a ride. No jets. It was a bolt on and go for me. I've read good things about the Smart carb.

 

[DFW_Warrior]

It honestly depends on the bike.

For example, my KLR, and WR live /lived down here in TX at 600’ and when they were up at the top of any pass in Colorado they were just fine too other than being a little down on power. Those are 4-strokes though so very different.

I will say that if it barely runs here I would most certainly not haul it all the way to Colorado in hopes that you will get it figured out once you are up at elevation.

 

[jbird710]

Just a suggestion; you might pose your question in the KTM 2 stroke sub forum on Thumpertalk. There’s probably someone riding your model bike that lives there and can tell you how it’s setup.

 

[Rydah]

Unless you are a reaaaaally light guy, I wouldn't suggest you try Ouray on a 250. Yes, you have to rejet for altitude, but there is only so much oxygen available, and O2 = power.

 

[2WheelNut]

In general, yes, you'll yave to re-jet going from 300 ft to over 10K feet of elevation. A 250 2-stroke will be down on power, but still serviceable at that elevation whereas a 125 or 100 2-stroke would likely be too under powered at that elevation. I once rode a YZ125 over Engineer, Claifornia, Stony and Poughkeepsie....but I had to wring it's neck to make power and I was only 180 pounds at the time.

Back to jetting....I go to that area often and find if I make the jetting about 8% leaner, it works well. I usually change the main, pilot and needle clip position to dial it in.

Having said that, I agree with 2 earlier posts. 1) Get it running right here before you go so you aren't chasing multiple problems there. 2.) JD jet kits have this figured out and is much easier than figuring it out on your own.

 

[Dao]

i took my cr250 to ride in Ouray area one yr. , rode it in ironton, corkscrew , silverton, thunder trails in norwood & Peach Valley in Montrose

Before trip,
I got my 250 jetted well enough & running crisp for austin in July @ 95F, 660ft elev.
Carb=Keihin PWK 36mm (off 2006 KTM 250xc)
Pilot = 38
Main =165
Needle = Sudco DDK, clip #2 (from top)
----------------------------------------------------
For Ouray & Montrose,this is my rejet to work for 60F & 9000 ft ASL:
Pilot=35
Main =162
Needle=DDK, clip #1

Basically, i went one size smaller on pilot & main, moved clip up one notch . That got my jetting where it needed to be for the rocky mtns.... bike ran crisp, pulled great, and most importantly, it kick started on 1st kick every time w/ hardly any spooge running out of pipe.

I'd Get your bike jetted right for the summer temp & elev. now, and then for Ouray, drop your main & pilot one size smaller, and move needle clip one groove up before leaving. And for insurance, bring a couple extra spark plugs, & plug wrench.

and, if you don't have these two thumb adjusters on side of your carb for tweaking your idle & fuel screw while riding, you may want these installed before trip.

a 1/8 turn on your fuel screw makes a diff.

Tusk Carburetor Adjustment Screw Kit

The Tusk Carburetor Adjustment Screws are a great addition for those 2-Stroke lovers!! They replace your stock Carburetor Air & Idle Screws and allow you to make the necessary adjustments on the fly without the use of tools. They are made out of 6061-T6 Aluminum and anodized to give you that...

www.rockymountainatvmc.com

 

[Fritzcoinc]

Thinking of taking my 250 ktm to ouray.
It barely runs well with me screwing with it here, and i bet it will be crap if it take it to engineer pass as is.
Question is do you have to rejet bikes for altitude or can they be adjusted?
Does anyone know of an idiots guide to carb tuning?

Contact a KTM shop in Colorado for jetting recommendations.