yet another no idle thread.

so i raced the bike yesterday (saturday race!)

once it got hot, it would get real flat/lose power/stop accelerating on uphills if i was about 1/2-wot. so i would constantly upshift and try to run 1/4-1/2 throttle...where it ran the strongest, and didn't give me the unnerving is this gonna blowup? feel... i pulled the plug today, it's lighter than i would like. i'm thinking i have the float set too low (i had it at about 18-19mm), as i lowered it in the past to eliminate pulling over. i'm doubting that 180 main/jd red #4 is lean. i'm resetting the float height, and gonna give it a try. it's really hard to jet for race conditions in your yard. no matter how much space you have. any suggestions?

i can go to 182 main, but i would think that is obnoxiously rich? with the ddk i was on a 172 main in hot weather. i don't know taper/spec on the jd needles to compare...
 
First stick to your plan and set the float, then main if needed. Somewhere deep in the KTMTalk archives from a few years ago he discusses in a post that the Blue and Red needles are based on existing needles with additional or relocated tapers. I'll look as its possible I have this saved in my notes somewhere. I know the Blue is DDK based but the Red is based on some other OEM needle. You know that the straight section is correct. If its the needle then the taper is the problem, so you need a more aggressive taper from 1/2 throttle up. You can get clever with a good caliper or micrometer and get a rough idea of the dia at that mid to full throttle area, and compare that to some known C and OEM taper needles with the same straight dia. JD isn't going to tell you anything if you ask about #s, that's why the needles are omitted from his spreadsheet.

At one time we had an optical comparator here at work. I could have figured that needle profile out in no time with it.
 
i've tried richer and leaner on main, and on the needle. where i was at is right. fixed the float and it helped, but there is still this unnerving lean bog/flat spot at say 3/4 throttle - its hard to pin point. i am going to see if i can figure the taper and the transition points (these are 3 taper right?) with my mic. as you said, i'm assuming the bottom taper is too long, not aggressive enough. i'm gonna mark where the problem is on my throttle, and then mark the needle position, then start measuring.

i liked the ddk because it is so linear. the red needle has nice hit at the right points, but if it's not gonna work, it's not gonna work.
 
stainlesscycle said:
i've tried richer and leaner on main, and on the needle. where i was at is right. fixed the float and it helped, but there is still this unnerving lean bog/flat spot at say 3/4 throttle - its hard to pin point. i am going to see if i can figure the taper and the transition points (these are 3 taper right?) with my mic. as you said, i'm assuming the bottom taper is too long, not aggressive enough. i'm gonna mark where the problem is on my throttle, and then mark the needle position, then start measuring.

i liked the ddk because it is so linear. the red needle has nice hit at the right points, but if it's not gonna work, it's not gonna work.
Click to expand...

I agree set the float and then investigate. I experienced the same thing running N3CH 1 clip higher than usual. Power flattened out and some light pinging experienced at part throttle and only under load (ie hill). Still pulled well bottom and top. Had to drop the clip again. All good.
 
i tried going to #5 on the needle and it didn't seem to help. maybe i'm too rich on the top and too lean on the needle with 180/#4. maybe 178 and #5 - although that sure don't sound right. kinda hard to pull the choke when i'm at 3/4 throttle to see if it's a lean condition. i can't get it to ping with 110 in it so i can't use that indicator.....
 
Can't wait for direct injection.

Being a triple taper needle these things can happen. I find the same thing with some of the N3 range being that to get it right at 1/4 throttle I then get too lean around half throttle.

Have you tried the richer JD needle?
 
ordered 4 needles today.

ccm,ddm, cel, and den. they are all very similar to ddk after 3/8 throttle. they all should idle in hot weather (cel may not), they just have slight rich/lean adjustments at 1/8 - 1/4 throttle...


we will see what happens..
 
pwkchart.jpg
 
FWIW

Jim provided me with Swiss Army Knife jetting when he shipped my 2001xc300. When I am disciplined enough to keep my carb clean instead of painting polka dots on stuff, this setup was good enough for reliable fun riding in a variety of conditions.


So, just for another baseline to run off of:
New England - three seasons - 0-1,000 feet and then some.

#7 slide (stock, I believe)
180 main
48 pilot
mystery needle - I can only read CC on the needle. There's a scuff on the needle before the CC, but I don't think it's hiding anything. If I'm reading my micrometer right, the straight diameter is ~ 0.1052 inch or 2.67462mm. So maybe that's a CCH?
Clip in position 2


http://www.carbparts.com/keihin/needles_tuning/jet_needles/pj_34_39_jn.html

**************
In any case, I'm taking this thread as an opportunity to finally understand that device I avoid adjusting.
So, thank you for your agony. ;)

You have probably already tried this, or it's way off where you're headed. But I would not want to be sitting on the hot setup and not share. YMMV.

-dean
has never been very sophisticated about carbs. But I'm willing to learn.
A 300 that is not quite maximized remains quite potent. All I need is a shiteating grin. :D

Mediocre stereos sound OK too, if the music is good enough.

P.S. I will try to dig up my Idaho jetting - 7,000 to 10,000 feet closer to Heaven.
 
stainless,

Thats a good plan, lean straight dia and richer tapers. The JD Red is a triple taper but it very subtle. All his Red option needles are typically used for higher altitudes.

If you start getting off the map though, with less leaner straight section needles available, lean the slide to a #8 and you can go back and work with the more normal/richer straight sections that are more plentiful in choice.
 
the problem i found with tapers is there's a big jump from 1.45(D) to 2.00(E) degree tapers - i don't think anyone is running e series needles....right? i could go with a shorter needle to achieve similar effect - but shorter needle affects earlier in throttle position right?? i'm gonna experiment with the strange needles (like DEN) and see what happens..
 
DDM #3, 45, 2.5, 175 main gets me very nice idle, and very smooth power delivery. no lean spots like the jd red. i like the jd red for the hit, but the ddm is so predictable and smooth. now if i could just get a little bit more outta the mid like the jd red had, that would be nice. i'm not sure which needle would have another taper so i get a little more juice out of the mid - the ddk/ddm are basically the same - and have a nice feel, but it would be nice if they didn't feel flat at the mid/top - don't get me wrong - the power deliver is electric smooth, which is great for the woods, but i'd love to have a small hit at 1/2-3/4 throttle...so i can loft the front wheel at speed and clear ditches/logs, without shifting/changing up.




.

i will play with den/ccm/cel when i get a chance.
 
Last edited:
stainlesscycle said:
DDM #3, 45, 2.5, 175 main gets me very nice idle, and very smooth power delivery. no lean spots like the jd red. i like the jd red for the hit, but the ddm is so predictable and smooth. now if i could just get a little bit more outta the mid like the jd red had, that would be nice. i'm not sure which needle would have another taper so i get a little more juice out of the mid - the ddk/ddm are basically the same - and have a nice feel, but it would be nice if they didn't feel flat at the mid/top - don't get me wrong - the power deliver is electric smooth, which is great for the woods, but i'd love to have a small hit at 1/2-3/4 throttle...



.

i will play with den/ccm/cel when i get a chance.
Click to expand...
remind me what carb and slide you're on? If I could get mine running and idle I'd be pretty happy. If not I think I'm going to go the squish mod route.
 
38mm/#7 slide / 00 300 motor, 2k2, 9 oz fww, messico pipe... 1.2ish squish (via thinnest base gasket..), timing retarded 1 degree.
 
Tuning limitations among other things. Swaping them out for PWKs on Huskys is a nice improvement.
 
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