Y2K 300 EXC Jetting

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#1
Hi,

I have just purchased a 2000 300 EXC to replace my 98 KX250 for woods duty in Tampa, FL (Hot,Humid, and Low Elevation). I have searched to archives but have not found anything that relates close enough for me to use. I have the manual, but would like the opinion of someone who has gotten their bike "Right". The bike is all stock and in Like New condition.

The original owner ran the bike with a 20:1 mix I have no idea how he came up with that. Will I need to clean the power valve after such a spooging? How 'bout the pipe and packing?

I would like to run the bike on 92-93 Octane Pump gas with Belray H1R oil at 60:1 unless their is a better more reliable mix.

Power Valve adjustment? Not quite sure how this works. Any insight on how this should be set for riding mainly in Florida sand would be appreciated greatly.

Thank-you
t_bare
 
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JMD

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#2
Try these settings. They work great on my '99 300 E/XC. Of course, every bike is different, and air density varies, so these are just starting points. But I ride at 0 to 3,000 feet in hot, humid Texas, and my 99 300 E/XC runs very crisp at these settings. It has a stock pipe and reeds.

pilot - 48 slide - 6.5 needle N85C-2 main - 172

You may find that on the 92 octane gas you have a little clatter under a load. I recommend Super Hunky's mix of one gallon race gas to four gallons pump gas. VR's gas is good, though it's a blend, and some purists don't like that. Phillips 66's Base 32 is comparable in price (about $5 a gallon) and is not a blend. Both are pretty readily available. I use the B32.

As far as oil, Ive tried a lot of them. Nothing smells better or protects better than Maxima's Castor 927, but it's dirty, dirty stuff. It will spooge your muffler, drip down the headpipe, and encrust your power valve. LCR racing here in Dallas recommends Motul 800 at 66:1. I am plannig to adopt their recommendation, and will report on results.

Good luck with your 300. I love mine. I had the four-stroke bug pretty bad recently, and rode every KTM thumper at the dealer. Honestly, that cured me. I wouldn't trade my 300 straight across for any one of them (let alone for an inferior brand). They're heavier and more sluggish. I like a nimble-feeling bike, and they seem to lumber. Might be great in more wide-open stuff, though. I ride mostly woods.
 

Magoo

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#3
I ride Michigan woods, elevation is about 600 to 1100 feet, temps normally in the 70's, but lately in the 80's with something like 90% humidity (yuck!). Am running a 42 pilot, stock slide, CEK needle (1369J) in the middle clip, and a 178 main. I run Amoco 93 mixed 44 to 1 with Motul 600 2T. Bike runs quite nicely, with minimal spooge. I am going to try the CEL (1370J), due to the higher than normal humidity we're experiencing....
 
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#4
Thanks guys,

I am not sure I understand what you are telling me for the needle numbers. I thought I was looking for something like NOZH 2nd Clip.

Carb has: Slide#6, 170 main, 45 Idle, NOZH 2nd Position.

Thanks,
t_bare
 

Magoo

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#5
The NOZH needle never worked right for me. There has been quite a bit of discussion regarding jetting these bikes, and the single taper needles (like the CEK, aka 1369J) seems to work well for these bikes. You need to be careful on the main jet, you may need to go to a bigger main since these needles run leaner on top.
Many have gone to the 6.5 or 7 slide, which may improve your jetting with the NOZH needle --but, needles are $10, new slide is $75+ -- I had good luck with just the needle change.
Try a search to review the past discussions. A fellow by the name of James Dean has posted MANY very helpful thoughts -- he really knows this topic (I have him to thank for my jetting success!)!
 
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#6
Thanks Magoo,

I have been searching and reading. I agree James Dean seem to really be on top of this jetting game. Boy when you are just starting to learn this stuff is confusing!

I think I have found a good starting point. NOZI-2nd, 42, 172, 6 Slide.(I hope so the parts are on order!)

t_bare
 

Magoo

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#7
NOZI needle did not work for me -- but it may for you -- give it a try! I hope your dealer isn't selling you a #6 slide -- that should be the stock slide you have in your carb already... maybe he's getting the #7 for you? The number of the slide is stamped on the bottom of the slide (just so ya know).
 
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#8
Yea, I've got the #6 slide, I am just ordering jets and needle. Thanks for your help. I am sure our jetting will be a bit different. I am probably 1000ft lower altitude than you and our humidity is through the freakin' roof!!!

Thanks again
t_bare
 

clw

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#9
66:1 Oil Mix?

Any bottom end problems when using Motul @ 66:1? That sounds REAL thin on lube, is it that good?
 
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#11
Jets came. Now I am waiting on a #7 Slide.

After Jetting
40 Pilot
172 Main
#6 Slide
NOZI#1

The bike ran pretty good, but I soon learned the previous owner removed the silencer packing (I know "what the puck" was he thinking?)

After repacking I had to increase the pilot to a 42. The bike runs pretty good with a slight burbble about 1/8 - 1/4 open.

I am in hopes that the number 7 slide is the ticket!

I know many people are scrapping the Noz series needles. Is the CEK with a 178 main the right combo?

I am in Florida about 60 feet above sea-level! The humidity here is average about 76% and the temps average about 88degs when I ride

Thanks
t_bare
 

Strick

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#12
Yes, immediately go the the 178 with the single taper needle. You will be able to dial it from there if necessary. At your temps, and altitude you are going to be close with the 178. Start with the middle clip on that needle. Post back and let us know how it is going. With the #7 slide you are probably going to have to raise the needle one, and maybe even bump the pilot. Don't do this right away though. Do every change on step at a time, except the needle and main, those need to be done together.
 
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DanS

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#13
Since you already have the #7 slide coming try that before you change the needle. It should clean up that 1/8-1/4 throttle for you. Most guys do find that the straight taper needles like the CEK work better for their bikes. However some guys find the the double taper NOZ type needles work well. It wouldn't hurt to try CEK and see how it works for you. The combinations are endless. The #6 or #6.5 slide may work better with a CEK than NOZ because the CEK is leaner at the begining of the throttle opening. I have gone to a DGH with a #7 slide, 42 slow jet, 172 main but my weather and altitude are way different than yours. Your on the right track just remember you only want to change one thing at a time until you find the right combo.
 
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#14
Thanks Men!

I should get my slide on Tuesday with any luck I should be able to do some field testing. after that I will start roundng up more needles and jets.:scream:

t_bare
 
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#15
:cool:

Yippie my parts are a day early!!!

I have to plug E-Rider. These guys are great!

#7 Slide $59.95 Ordered by phone on 8-10-01 on my desk 8-13-01

Can't wait to give it a go! It seems as you get closer to being properly jetted the more exciting it becomes!

t_bare