Jump to content
Sign in to follow this  

KTM 300 EXC, baseline jetting

Recommended Posts

TT,

I have a '00 300 EXC that i'm working on for a buddy. Previous owner "knew how to work on bikes", well in the process has screwed the carb all up. From jets to needle positions and fuel screw. Basically I'm looking for a good baseline jetting, needle clip position, fuel screw turns to start with.

We ride in Maryland about 10 mins from Budds Creek, nice and humid here with about 80-90 degree temps. He's a decent C class rider. Any suggestions???? Ill be tearing into the carb tomorrow morning, Ill post the current specs and jets then

Thanks in advance!:smirk:

Share this post


Link to post
Share on other sites

I have an '02 KTM300 EXC. I have the following specs: pilot jet is a 42 in summer, 45 in winter, CEK needle with clip in 2nd pos. from top/3rd pos. in winter, 172 main jet in summer and a 175 in winter, airscrew about 1 1/2 turns out. Hope that helps

Little Jeff

Share this post


Link to post
Share on other sites

thanks for the input. my specs are as follows:

Pilot: 45

Main:175

Needle: NOZH 3rd clip from bottom

Fuel Screw: about 2 turns

Forgot to add it has a FMF gnarly pipe, titanium 2 silencer, power now carb insert, v force 3 reeds.

Cleaned carb out. started 3rd kick. set idle screw. starts first kick now...runs like crap though, super rich. Tomorrow i'm going to a 42, 172, new plug and better fuel/oil mix. idles and putts around great, any throttle at all and its choking up. need to double check fuel screw as well.

Share this post


Link to post
Share on other sites
thanks for the input. my specs are as follows:

Pilot: 45

Main:175

Needle: NOZH 3rd clip from bottom

Fuel Screw: about 2 turns

Forgot to add it has a FMF gnarly pipe, titanium 2 silencer, power now carb insert, v force 3 reeds.

Cleaned carb out. started 3rd kick. set idle screw. starts first kick now...runs like crap though, super rich. Tomorrow i'm going to a 42, 172, new plug and better fuel/oil mix. idles and putts around great, any throttle at all and its choking up. need to double check fuel screw as well.

just remember that the main jet has no play till WOT, so if it is blubbery down low, work with those circuits and use a plug chop or wet oil line method for the main. the NOZH series is known to be blubbery down low. There are better needles.

Share this post


Link to post
Share on other sites

new plug brand new 93 octane fuel mixed 40:1 and its still terrible. idle and minimum throttle are good, pulls front wheel no problem. but once u go past 1/4 throttle its bad. could the powervalve be an issue??? Is there a seperate fuel screw on this carb? the only one a see is the idle/air screw (black knob with spring behind it). still waiting on the 172mj and 42 pj, it should still run better than it is now even with the 45 pj.

Share this post


Link to post
Share on other sites

There should be two screws.

The black one with the spring is the idle screw, to the lower right of this screw you should see a brass screw. It is just above where the float bowl attaches to the carb, this is the air screw. It may be covered with dirt.

check the ThumperTalk parts store, I think they have exploded views.

Good luck!

Share this post


Link to post
Share on other sites
new plug brand new 93 octane fuel mixed 40:1 and its still terrible. idle and minimum throttle are good, pulls front wheel no problem. but once u go past 1/4 throttle its bad. could the powervalve be an issue??? Is there a seperate fuel screw on this carb? the only one a see is the idle/air screw (black knob with spring behind it). still waiting on the 172mj and 42 pj, it should still run better than it is now even with the 45 pj.

That is the issue the nozh needle causes. Ditch the the needle and then tune it. There are much better needles.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×