jetting changes?

Nic · Post by **Nic** » Mon May 24, 2004 10:41 pm

Is it necessary to change the jets from glamis jets to run here? If so does anybody have any recomendations on what to run on a cr250 with and also a crf250?

Washroad · Post by **Washroad** » Wed May 26, 2004 7:05 am

Since the Coral Pinks are at about 6000 feet elevation, you may need to go down in size on your main jets. I would get a few sizes smaller for each of them and then see how they perform. Can't recommend a particular size as you'll have to see how they run, and do a few "plug chops" on the 2 strokes to get an idea of what to do.

RichB · Post by **RichB** » Thu May 27, 2004 4:01 pm

My experience is as follows:

Modern Thumpers need to be leaned out at least 1 main jet size and 1 position on the needle clip position. Also, adjust the fuel screw (leaner)
as needed. Note: You can probably get away with your stock jetting w/out fouling but they'll run pretty fat and sluggish.

Smaller 2-strokes i.e. 200cc and below are ok to be left at your closer-to-sea-level type jetting because the sand at CP is so deep and taxing. The smaller 2-strokes have to work really hard to plow around through that particular type of sand and as such they will run hotter than what you'd think.

Medium-to-Big Bore 2 Strokes. A 250 MX bike may or may not be good (depending on each engine/riding style of the rider) with your sea level jetting. I would roll up with the stock jetting and ride around a bit to see how it acts. Big bores (500s) you can lean out 1 main increment and call it macaroni.

Again, these are just my experiences coupled with the other folks we roll up there with. With that said, I think the bottom line is you shouldn't have to carry a sack of jets and be spending a huge amount of time tweaking your stuff to be able to ride there.

Good luck, be up to speed on the rules there before you go and have a great time!

OBSESSED · Post by **OBSESSED** » Thu May 27, 2004 9:06 pm

I agree with Rich.

And I'd like to add,
when I had a 250r, I did nothing to the jetting. I just ran it, yes it had less power than at sea level, but, you'd be on it for a shorter distance also.

St Anthony is another story. 4800-5200'
We actually ran leaner in our rails because you'd be on it for such a long time, boosting, that you'd run out of fuel!

Glamis you might be on boost for 7 to 10 seconds at a time.
St Anthony you might be on boost for 30-40 up to 60 seconds at a time!
Coral Pink 2-3 seconds of boost.

My worth nuthin' 2 cents.....

iggys-amsoil · Post by **iggys-amsoil** » Fri May 28, 2004 1:12 am

Stock jetting is ok. I ran with my Glamis jetting it was a little fat with the richer 1369 needle third notch. #52 pilot and 175 main.

the rest here.
http://www.iggysoil.com/cr1.html