any help on Keihin CDK2 jetting?
- Thread starter tor*p*do
- Start date
Your pilot will end up somewhere between 80-85 depending on your popoff and how rich you want to be at 1/4 throttle. A 165 main may be too big in the 40, try a 150 with the top needle open 2.5 turns and lean down. If it ends up over a turn out then step up to a 160. The stock 40 is very easy to tune but will limit power compared to a 42. The best single carb setup that I have run is a K42 on a PJS manifold but these are almost impossible to find. I tried a Mikuni 46 and it was better for freestyle but had problems going lean at full throttle.
shawn_NJ
Chasing waves.
- Location
- Daytona Beach
Call Groupk, Harry has the jetting for the 42 to the point that you will not even have to touch it. I lost the paper that I wrote the settings down, but my K750 ripped pretty good with it.
EDIT: Nevermind I just notice you have the 40 on there.
EDIT: Nevermind I just notice you have the 40 on there.
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N3vrSat1sfied
Military Member
- Location
- Fort Worth, TX
i dont remember what my main jet was but i know the low was a 72 in my 42 cdk. I should be able to look at my book with all my important stuff i write down tonight. I will let you know. I know i bumped up one size on my low and my main since i put all my new mods on but i havent tested that yet.
What i do is start with the stock settings on the low/high speed screws. i think its like 5/8 and 1 1/4. Then change the main jets untill you get it close(without changing the screws) then finish fine tuning with the screws if need be.
What i do is start with the stock settings on the low/high speed screws. i think its like 5/8 and 1 1/4. Then change the main jets untill you get it close(without changing the screws) then finish fine tuning with the screws if need be.
N3vrSat1sfied
Military Member
- Location
- Fort Worth, TX
ok never mind i got it right here. I ran a 140 main and 72.5 low when my only mods were the 42 carb and the same coffman exhaust you have. Seems low but it worked with no problems. I use Amsoil dominator at 40:1 as well
yours will be a little higher since you have a smaller carb. I say you will be about right on with 80-85low and around a 160. but each motor is diffrent.
whats going on with your cooling lines? the one right below the coffman logo should be a pisser. i beleive check my build thread for all the ways i have routed my lines
yours will be a little higher since you have a smaller carb. I say you will be about right on with 80-85low and around a 160. but each motor is diffrent.
whats going on with your cooling lines? the one right below the coffman logo should be a pisser. i beleive check my build thread for all the ways i have routed my lines
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craig -thanks for the tips. I ordered a 80 and 85 lo and a 165 hi
so I have 75/80/85 and 155/165 so I should be able to dial it in.
Start fat and lean it out a bit at a time:scratchchin:
same order should have my bypass fitting to tie in the pisser
from below the coffman logo
second output on head will go to the ebox overtemp sensor
then this thing should rip!
so I have 75/80/85 and 155/165 so I should be able to dial it in.
Start fat and lean it out a bit at a time:scratchchin:
same order should have my bypass fitting to tie in the pisser
from below the coffman logo
second output on head will go to the ebox overtemp sensor
then this thing should rip!
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WFO Speedracer
A lifetime ban is like a lifetime warranty !
- Location
- Alabama
Contact coffman and see if they can provide jetting specs for that pipea
BruceSki
Formerly Motoman25
- Location
- Long Island
coffman wont give you jetting specs... ive tried before..
they say oh we cant recommend a starting point because every motor/setup is different.
they say oh we cant recommend a starting point because every motor/setup is different.
I tried that, Pam Coffman wrote back,
"This is the very original Hurricane 750SX system. Basically in the archives at this point. Don't know what the jetting would be with your carbs. Might want to take it to a professional. No matter what, start rich.
Kind Regards,
Pam Coffman"
but I think I can get her dialed in. Carb that came with it was 75/155
and I am going richer so I should be OK.
cant be as efficient as a FPP and they say 88/155 for it, so . .
N3vrSat1sfied
Military Member
- Location
- Fort Worth, TX
ya just start rich for sure! easier to go down the up. if you start to lean you will think the thing just rips and wont want to riching it to safe running. Lol
Mark44
Katie's Boss
- Location
- 100% one place
o
Start with this and put a tach on the motor and change from there you can't go wrong.
Mark44
Start with this and put a tach on the motor and change from there you can't go wrong.
Mark44
ran it yesterday with a 85 lo/165 hi and 1 1/4 turns each.
ran great, nothing I could do to tweak it one way or another
to make it run better
runs strong and added more than 5 mph to the ski
will pull plugs and check piston wash tonight, but it wouldn't bog or hesitate at all! :Banane01: :Banane01:
ran great, nothing I could do to tweak it one way or another
to make it run better
runs strong and added more than 5 mph to the ski
will pull plugs and check piston wash tonight, but it wouldn't bog or hesitate at all! :Banane01: :Banane01: