DMM



16 replies to this topic
  • Taffy

Posted March 17, 2002 - 12:38 AM

#1

for those of you who DON'T want YZ timing and want that WR rattling stomp off the bottom i would recommend the DMM needle.

it could even be a better needle than the EMM that i recommend for YZ timing.

let me explain.

we all like that thin 'E' series needle. the bike gets more fuel and it goes like a rocket. so far so good.

after getting the jetting spot on though the 'D' needle doesn't appear to be the "blockage" it once was. the 'DMM' needle can be just as good and even better in wet grass etc where you want to do a 90d turn and not whizz into a 270d turn!!

the reason the DMM may be a better needle is because we have to set the needle for the midrange throttle. the second setting on the needle is the "straight". the one thing you can't dictate is when the taper starts. you're stuck with it.

take the point where a DMM and an EMM are the same diameter on the taper, now because the taper on the DMM is less it won't reach the start point for about another 3mm up the needle. i hope you follow.

this means that the DMM needle taper will start 3mm earlier than the EMM. this will help 0-1/8 and 0-1/4 throttle response and should make them wheelie monsters.

it needs someone who has the EMM needle to try the DMM back to back. a little low end work on jetting may be needed but it will be a question of which wins?

a gain in low end closed throttle snap and response versus any (if any) loss in midrange.

i hope someone will try it sometime.

Taffy

  • Tim_in_WA

Posted March 17, 2002 - 03:03 AM

#2

Good timing on this post Taffy. I was just getting ready to try an EKP in my '00 with WR timing. My current jetting is listed below. I'll order the DMM, but try the EKP in the mean time. I ride a lot of single track, and the more low end grunt the better.

  • Guy

Posted March 17, 2002 - 11:46 AM

#3

:D Taff, the DMM is nice, I am well impressed with it :D You are right in that, the bike wheelies and wheelies and wheelies or it would if I could do it LOL!, The bottom end is superb, and now I'm close with my jetting, I can't really fault it!
I may try the EMM later on when I've recovered from this! :)

  • James_Dean

Posted March 17, 2002 - 07:14 PM

#4

Taffy,
Good suggestion. I will be interested in hearing any results too.
Look back at your notes. Remember the day you lost 5th gear? Running DVP#7-8 is the same as DMP#3-4! Was that a coincidence?
Did you know I'm riding a '02 400EXC now?

Guy,
Would you mind sharing your current jetting?

Tim,
A close approximation would be to put your DRQ needle in clip #6 (DRQ#6=DMQ#4). This gets the taper to crest the nozzle nearly the same as DMM#4. If you like bottom end torque, this will make a bunch of it. Check if there is any 1/4 throttle richness too.

Back to back proposal: EKP#5 & #165 main vs DMM#4 & #170 main

Correct me if thats wrong Taffy...

James

[ March 17, 2002: Message edited by: James Dean ]

  • Taffy

Posted March 17, 2002 - 10:39 PM

#5

JD

good choice of machine james. i've got the husey and on my list of advantages and disadvantages the disadvantages read just one; no keihin carb!

you never used the MK1 carb on your Y2K WR so you'll have to do an APJ mod. i note that they like the EMN needle over at site orange. not so far from us.

it was a DXM i ran on clip 8. which is a DMM on clip 3.

ok lets get technical-

if you read up there are a few people going for the #160MAJ, the lean PC system etc and they really like it. the open pipes seem to need about another 5/8 on the MJ.

i feel that the 'D' needle isn't that restrictive if riders use the 160MAJ. this allows a lower MJ and a higher needle clip.

note; anyone with JD's needle comparison chart can compare a DMM to a EMM and see that the tapers start at different points on the needle.

i feel that the gain at the bottom will outweigh any (if any) loss in the mid-range.

if most riders trail ride, ride in M & S, then the actual riding benifits become probably treblefold. in all but the driest weather here in the UK i find that the midrange just ripped all the traction out. a WHIZZ it most definately was :) :D

unfortunately it was a whizz on one spot!

your jetting figures at the bottom of your post look good with the standard #200MAJ. with the #160MAJ it would be down 10-12MJ and up one or two clip positions.

Taffy

  • Guy

Posted March 18, 2002 - 09:13 AM

#6

:) My (nearly) final jetting is :_

MJ...162
MAJ...170
PJ....42
PAJ...75
SJ....62
PS...1.5 turns out
DMM on clip#1
White bros air filter, E-Series with 8 discs, and airbox lid ON! (water ingress problems...its wet over here!)
I have done the Taff mod to my APJ but I dont know the squirt/gap as I adjusted it yesterday to get rid of a hesitation, and I haven't checked it yet :D Oddly enough, I had to richen the squirt! :D

  • Taffy

Posted March 18, 2002 - 02:26 PM

#7

hello guy

it's been said by me before but you either lean out or richen up to get rid of that flat spot. time and again it has happened.

your MAJ could be a #160 which would lead to the MJ coming down to a 158/160 and the needle being lifted a clip to DMM #2. the PC could go the whole hog-but you knew that anyway. then your APJ could be backed right down.

Taffy

  • Rich_in_Orlando

Posted March 18, 2002 - 02:38 PM

#8

What flat spot? :)

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  • sbohanon

Posted March 19, 2002 - 02:05 AM

#9

anybody know the yamaha p/n for the emm needle?

  • Tim_in_WA

Posted March 19, 2002 - 03:24 AM

#10

And since we're talking p/n's, anybody know the # for the DMM???

  • Guy

Posted March 19, 2002 - 08:55 AM

#11

:) Taff, Thats why I had (nearly) LOL! :D
I know there is room to improve, but at least it is small bits now, fine tuning as it were, when I think back to how the bike used to be, it is hard to believe that changing a few bits of brass, for another few bits of brass would make soooo much difference,
I also must say ,I wouldn't have got this far without all YOUR help...cheers mate! :D

  • James_Dean

Posted March 19, 2002 - 09:13 AM

#12

Needles DMM and EMM are brass and are not sold by Yamaha. The needle codes that start with OC are made from brass. - OCDMx and OCEMx for example. These are only available from a Keihin aftermarket parts supplier (Sudco, Carb Parts Whse, DG).

There are Yamaha needles that will do the same thing. These are hard plated and start with OB - for example OBDTM, OBDVR, OBEKR, OBEJP.

If you want OCDMM and OCEMM, call an aftermarket supplier. These are usually out of stock because of our internet discussions. :)

If you want an equivalent Yamaha needle to OCDMM the closest thing would be OBDRM. The closest to OCEMM is OBELM.

OBDRM - p/n 5GS-14916-RM
OBELM - p/n 5NL-14916-EM

See www.carbparts.com for the needle code descriptions.

James

[ March 19, 2002: Message edited by: James Dean ]

  • okieguy

Posted April 03, 2002 - 04:08 AM

#13

James,
I went to yamaha to get the
OBDRM - p/n 5GS-14916-RM

They could only find the

OBDRN - p/n 5GS-14916-RN

Is this the correct # or are we looking in the wrong place or do I just need to contact Sudco for the brass needle?

Thanks for your help.

Guy

  • robman

Posted April 03, 2002 - 01:05 PM

#14

Who did you order the DMM needle from and what was the part # ? please

  • James_Dean

Posted April 03, 2002 - 07:56 PM

#15

The brass OCDMM needle is available from Sudco and you don't need a part number. 1-800-998-3529 or www.sudco.com or www.carbparts.com .

The OBDRM part number from Yamaha came straight out of the '00wr400 manual.

  • Taffy

Posted April 03, 2002 - 11:00 PM

#16

the DMM i recommend runs on a very high clip setting of either 1, 2 or at best 3.

if the DRM is available i would get it. it's hardened and the needle will sit two clips higher at clips 3,4 or 5. THIS WOULD BE PERFECT.

go for this one lads. i didn't know yam made this needle. which model and year is it off JD?

Taffy

  • James_Dean

Posted April 04, 2002 - 06:26 AM

#17

The needle OBDRM is shown as an option in the '00WR400 manual on page 7-8. I just purchased needle OBDRN (5GS-14916-RN) after the interest in needle OCDMN which is close to OCDMM. When there's a moving target, I like to pick in the middle of the scatter. :)

Based on that, OBDRM should be available also (5GS-14916-RM). It doesn't have to be in the fiche to be available. This wouldn't be the first time the parts dept was wrong. :D

[ April 04, 2002: Message edited by: James Dean ]




 
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