Jetting 45 deg. VS. 85 Deg. air temps ?

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Oldschool
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Jetting 45 deg. VS. 85 Deg. air temps ?

Post by Oldschool »

Hello
(Last jetting question,I Swear)!
In the past (MX_ WOT)I have only had to change the Main leaner one size for every Ten degrees @.
How often do you (If at all) guys change your Pilot and Needle as the Temps Rise / Fall ?

Thanks
Tony
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bradf
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Post by bradf »

I change main at 20 deg. I also change pilot, I use 40 for 55-85 and a 42 for below 55.
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canyncarvr
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Post by canyncarvr »

20º sounds about right, main and pilot. Clip/needle stays the same.

Keep in mind that an average riding day 'round here will see temp changes of 40-50º to start with.

No. I don't rejet in the middle of a ride because the sun came out. I do change the airscrew regularly (it works completely differently in a modified carb though)...maybe several times a ride.

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scheckaet
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Post by scheckaet »

Just to be sure, you all talking about celsius, right?

nevermind I just re-read the post...
Last edited by scheckaet on 12:17 am Nov 22 2006, edited 1 time in total.
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Post by AZRickD »

I'm running 150/38 CEK-3 right now and and have been since the temps dropped below 100F. When it was above that I would have a 148/35... right on the edge, lean-wise

I was considering dropping going to 152/40 as the temps get to under 60F around ride time, but I'm wondering if that will be too rich. QuailChaser did that last season I'm in no great rush.

Rick
Last edited by AZRickD on 09:47 am Nov 22 2006, edited 1 time in total.
I done KX-ed QuailChaser's KDX220R
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Indawoods
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Post by Indawoods »

That's uh, quite a combo there....
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Post by AZRickD »

Too cryptic, Inda.

Rick
I done KX-ed QuailChaser's KDX220R
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Indawoods
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Post by Indawoods »

Sounds pretty tight.
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Post by layoutd »

hmm, i feel pretty weak. My bike rides fine all year long with no adjustments. that's probably why a kdx is best for me, does it all, no matter what kind of moron you are. fortunately the guy who had the bike before me had the carb set up well before i got it.
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Post by KarlP »

I'm with layoutd. I don't make any changes through the year. Seems to run fine all around.
I do notice a difference, though, as the temperature changes. Clutch abuse makes all things equal. :lol:

One thing about a bike at a high state of tune, is that it is at a high state of tune and can come off of there pretty easily.

What do I know, my last bike was an XR400 and my first a CT70
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Post by AZRickD »

Indawoods wrote:Sounds pretty tight.
A'ight, Holmes. You got the shizzy on dat.

I think what you're saying, in your hep MX urban slang, is that it is jetted too lean and that the main/pilot combination are out of whack as I should be using a 45 or so.

Problem is if I go any higher in my RB-ed bike, the plug gets all gooky (during slow single-track) and my choke becomes useless (it wouldn't start with the choke on until I leaned out the jetting).

Keep in mind, in Phoenix, in the summer, I'm riding at 5am to avoid the heat and even then it's starting at 85F and climbing to 105F if we can manage to ride to 9am. As well, while Phx is at 1,200, where we ride can be up around 2,500.

Also, I ride kinda suckie, which we all know can be corrected with clever use of jets, needles, clips, and toluene.

Rick
I done KX-ed QuailChaser's KDX220R
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Indawoods
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Post by Indawoods »

Not saying it's wrong.... just sounds tight.
Running on the edge of lean like you said.

I don't have mine perfect yet with the DEK and Modified Head change but trying to get it dialed in. SO, I am reading all the jetting threads.....
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Post by IdahoCharley »

Comparing 220 to 200 jetting may not be the best thing to do. I've really got no clue since I haven't ever worked on a 220 but from what I've read on this forum..... :sad:
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Post by m0rie »

I seem to recall Ski's 220 running quite a bit leaner jetting than CC and mine 200's.
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Post by Indawoods »

I just thought the RB'd carb would end up being closer in jetting that the stock 33mm and 35mm. 20cc's ain't much.
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Post by m0rie »

20cc's ain't much, but the significantly tamer porting on the 220's is...

Ski also ran a FMF K-35 (Woods/Torque) pipe which generally takes a leaner setup than a K-30 Rev profile would.
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Post by 2001kdx »

>|<>QBB<
AZRickD wrote:
Indawoods wrote:Sounds pretty tight.
Problem is if I go any higher in my RB-ed bike, the plug gets all gooky (during slow single-track) and my choke becomes useless (it wouldn't start with the choke on until I leaned out the jetting).

Rick
The choke becomes useless? I believe my choke is essential to start the cold bike, and my jetting is 160/48. When I start the bike though, with choke, it revs pretty high without me touching the gas. Does anybody experience this?
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Post by m0rie »

Sounds like you might have an air leak somewhere.
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Post by AZRickD »

m0rie wrote:20cc's ain't much, but the significantly tamer porting on the 220's is...

Ski also ran a FMF K-35 (Woods/Torque) pipe which generally takes a leaner setup than a K-30 Rev profile would.
I also have a torque-pipe (PC Plat II) installed by QuailChaser. Maybe that's it? Perhaps SkiPro can shed some light on whether I should $wap my torque pipe for a rev pipe on my 220.
The choke becomes useless?
Indeed it did. During the hot summer month of July 2006 (highs of 115F & jetted 150/38/CEK-3), the bike would not start with the choke on, and if I started it with the choke *off* and then quickly put the choke *on*, it would stall. Power was a pit wimpy as well. I made the bold move of re-jetting to 148/35/CEK-3 and I got a nice ringa-ting-ting back in the exhaust, the plug wasn't all goopy and I actually *had* to use the choke to cold-start it. This temp extreme only lasts for a month, so I had to re-jett back to 150/38 by late August.

Keep in mind that while I did plug chops, I didn't cut the threads off to get a clear look at the deep part of the insulator. Next time...

Rick
I done KX-ed QuailChaser's KDX220R
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