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I have a race on Sunday (woohoo!) and I need some jetting tips. The race is about 3000-6000ft elevation and I *think* (it's been awhile since I've messed with anything) a 140 main, 42 pilot, stock needle clip on #2 and runs pretty (slightly rich) good at 7k' with temps in the 50-60 F range. There is no jetting loop and I have almost no time in the morning to mess around with the jetting.

Basically stock '02 220 with an FMF Rev and stock silencer. Nothing else has been done performance wise.

I looked through bike profiles and it seems that most people in that elevation have all sorts of mods that would affect jets that wouldn't pertain to me. What would you guys suggest I run? I know it wont be spot on but just a general range of sizes. I really appreciate the help!

Thank you!

Going lower in altitude makes the bike run leaner, just by looking at your jetting, I could be wrong but a 140 main jet seems a little on the lean side, Is anyone else here running a 140 main.

I can suggest that you may need to go a little richer on the main and pilot if you are dropping in altitude too what you usually ride.

Download JD jetting guide here http://home.att.net/~wbarrow/jd/JD_Jetting_2002_VS.zip
and input your current settings (assuming they are right).
then input your altitude temp etc for where the race is and you can see how it will afect your jetting, this will not be ideal for perfect setting but will give you an idea.

GhostRider wrote:Going lower in altitude makes the bike run leaner, just by looking at your jetting, I could be wrong but a 140 main jet seems a little on the lean side, Is anyone else here running a 140 main.

Touche, I pulled the jetting apart tonight and it's actually a 142 main, 42 pilot and clip second from the top.

I've been looking at that chart for alittle while now and not understanding much, when I type numbers in it moves though!

I'm trying to find someone else who jetted theirs for ~4500ft. I looked at the FMF jetting guide and they recommend a 145-148 and 142 at sea level. I have alittle bit of time for tinkering but not much, help is very much appreciated right now!

Isn't procrastinating a bitch?

the change of altitude you are making shouldn't make too much difference on the pilot or the needle, assuming you are jetted right and not to lean, i'd re adjust your airscrew and change the main to a 145.
You should figure out how to use jd jetting guide as it can be very useful for changing altitude.

If that jetting was slightly rich at 7K, then it would probably be plenty safe all the way down to 3K elevation. If it is slightly lean, the bike will tell you well in advance of anything bad happening. You might get a little lean bog is all. Lean bog is felt when you go uphill, slow speed, crack the throttle wide or almost wide open and it almost stalls before catching and bogging up the hill, trying to builld up RPM's. If that happens, bump the needle one position and leave the main jet alone. Chances are you won't be in the upper range of throttle for your race if its an enduro anyway. However, if it's a race where you are holding throttle at wide open for any appreciable length of time, I would just keep the next size main on hand. Just in case. I really, REALLY doubt you will need it.

I've taken my bike, jetted perfect for 6K elevation and have ridden it at 300 ft elevation on a hot day. It ran like a raped ape! No problems but also no mountains at 300 ft to climb either. It was all pretty much flat; maybe 100-200 ft elevation change. Our bikes seem to be very forgiving in the jetting department, both rich and lean. Too rich and she blubbers. Too lean and she bogs. Plenty of notice before you get stupid rich or lean. All IMHO, experience and all that.

(I've played A LOT with jetting, finding out what lean feels like. Believe me, you will know well in advance if you are getting too lean if you go 1 jet size at a time before causing any damage. )

Mr. Bleakness - For comparison purposes, before RB mods I ran a 140MJ, 40PJ at elevations <3000 and a throttle chop confirmed I was in good shape. So to Ski's point, you're very likely fine. In fact, you may STILL be a shade rich for the race . . .

GOOD LUCK ON THE RACE!!

I think I'm going to stay with my current setup. I saw in QCs profile he was running a 142main, 42 pilot for Phoenix altitude and this race is alittle higher than that.

The good thing about this race is it's actually a qualifier format. So for 5 miles or so I can ride at a brisk trail pace and then for a 10 mile test section I ride as fast as possible and then take it easy at the next transfer station. If I really needed to I can fiddle with the jetting during one of the transfer sections because they aren't timed, I just have to make sure not to hour out by taking too long.

I'm so stoked for this race! For me (C class) it's only 48 miles of desert ST but it's rocky gnarly stuff. The kind of terrain I love and most others I ride with hate!

Good luck!

Wow! That race was an absolute blast. When I heard that it was rocky I didn't really think much about it, this brings a new meaning to the term! It was seriously 40 miles up uphill doll head basketball sized rocks the entire way. I have no idea how many people I passed because their bikes were boiling over, tired, beat up, bikes in pieces or some other reasons.

The jetting was just about spot on, I never changed anything and it ran great from 3k-6k'. The main thing I learned from this race was that my suspension is somewhat lacking. It is wayyy to soft and I bounced all over the place, I haven't been this tired in a long time.

If you remember me saying in another thread that I hadn't met Steve Hengeveld before, well today I met him. I was in tech inspection and I turn around and have to take a double take because right behind me is a very familiar face. Another guy Bryant Cope came from New Mexico to race this one and he's incredible. IIRC he was the only AA riding a 2-stroke and man was he fast! Due to course layout I started one of my test sections right behind Steve Hengeveld and right before Byrant Cope, I managed to stay ahead of Bryant for a minute or two but he passed me right away.

There were over 200 riders, ~90 C-class, ~60 B-class, ~30 A-class, ~10 AA-class. I think this was my best showing in a race so far, all I'm hoping for is a top 50% in the overall C-class.

Whew, it was awesome!

Incredible experience!! Did you get any photos?

Me, personally no but the series photographer was there taking pictures somewhere. I never saw her (I never do) but others saw her taking photos one on of the uphill rocky sections *surprise*, I'll probably be flailing around like a goon. I know of some other sections where people were taking pictures of though, one in particular. I came around a soft burmed out corner WFO in 2nd gear and right in front of me is a good 5' tall rock step-up, I had no time to slow down so I gassed it over it. My suspension inst quite good enough to be taking big hits but I must have gotten a good 5' of air of this thing, I can't imagine what the pros right ahead of me did on that thing...

http://www.krockphotos.com/photos.html

Some of the previous race photos of me:
Laughlin U.S. Hare Scrambles on a 2004 Gas Gas EC200
http://www.krockphotos.com/gallery/2007 ... td_174.jpg
http://www.krockphotos.com/gallery/2007 ... td_391.jpg
http://www.krockphotos.com/gallery/2007 ... td_392.jpg

Kilauea Krusher II in January of this year:
http://www.krockphotos.com/gallery/2007 ... B-01KK.jpg
(Bad form...) http://www.krockphotos.com/gallery/2007 ... B-02KK.jpg

I'm trying to find the pictures of the first race I did, I know I've seen a picture of me from that one, I know she didn't take it and I don't know who did, hmm..

A true testament to the KDX is that they are raced still to this day. How many 10 year old bikes do you see competing. looks like a lot of fun.

Results are back! Turns out I got 3rd....in 250/450C. :D And 42/80 O/A C-class. Not exactly where I wanted to be but definetly my best finish yet! Not too bad considering I've been riding since October...

We shall see how long I'll be racing the KDX still, I'm thinking of buying a KX250 in the near future...

As long as you enjoy racing you will continue to improve your standings - guaranteed.
A KX would probably work better for the kind of racing conditions you have competed in - just get the suspension dialed for off-road. I used to race my KX in the desert and my KDX's for the tight, hilly local courses.

Best of luck in future races!

Cool pix, must be nice to not have to deal with mud all the time.. looks like a tough course.

Janik,

I wish I had seen this thread earlier. I wouldn't have changed the jetting, btw. ;)

How was that nasty, long, rocky, uphill section in Test 3?

I don't recall seeing you and your KDX at Check 4A/8A.

Rick

Test 3 was great, I had a blast going through that thing laughing all the way up. I had to take a breather acouple times though, along with many others.

I'm pretty sure I saw you, IIRC you were helping a guy tighten down some loose bars when I rolled in and then took right off behind Hengeveld and in front of Cope.

Did you ride the whole course at all on your KDX? If so, what did you think of it?

saddletramp wrote:Cool pix, must be nice to not have to deal with mud all the time

WORD

Good Job, looks like a Nice place to Race / Ride !

It's alright, those pictures were all taken in the desert south of where I live. I prefer riding in the woods over desert riding. It's nice not having to deal with mud but thats also been hurting us. We've been receiving less and less moisture over the last few years and they've had to close down the forest around my house. I'd rather take some mud and have healthy, wet forests over closed forests any day.

Some more pictures, these are in the close vicinity of my house.
http://i33.photobucket.com/albums/d93/j ... ure005.jpg
http://i33.photobucket.com/albums/d93/j ... ure009.jpg



I had one of my worst crashes about 10 miles before the first set of pictures was taken. The front tire landed on a rock that wasnt firmly planted and washed out, I cart wheeled into a tree while in the upper range of 2nd gear. My thigh (main part of my body that hit the tree) was swollen to about twice it's normal size and I had very little mobility in it for most of the week. Painfull stuff... I also have a video of me hitting the jump in one of those pictures below, I'll have to find it first...

http://i33.photobucket.com/albums/d93/j ... G_0624.jpg
http://i33.photobucket.com/albums/d93/j ... G_0617.jpg
http://i33.photobucket.com/albums/d93/j ... G_0616.jpg
http://i33.photobucket.com/albums/d93/j ... G_0614.jpg
http://i33.photobucket.com/albums/d93/j ... G_0612.jpg
http://i33.photobucket.com/albums/d93/j ... G_0618.jpg (yes that's me, I've cut my mop since then, I'm twice as fast now! )