Selecting a jet needle

kyan44
Topic Author
Offline
User
Posts: 38
Thanks: 1

Selecting a jet needle

27 Jul 2017 15:07

Hello guys! My carbs are running lean on 1/4 to 3/4 throttle. I have a:
jet needle: #6F5 on #4.
How do I know which needle to get to make the carbs run richer.? Any suggestions?

Please Log in or Create an account to join the conversation.

Nebr_Rex
Offline
User
Posts: 1887
Thanks: 295

Re: Selecting a jet needle

27 Jul 2017 17:56

#767851

Download the Sudco catalog.

2002 ZRX1200R
81 GPz1100
79 KZ1000st daily ride
79 KZ1000mk2 prodject
78 KZ650sr
78 KZ650b
81 KZ750e
80 KZ750ltd
77 KZ400/440 cafe project
76 KZ400/440 Fuel Injected

www.dotheton.com/forum/index.php?topic=39120.0

.

Please Log in or Create an account to join the conversation.

KZB2 650
Offline
User
Posts: 1475
Thanks: 265

Re: Selecting a jet needle

27 Jul 2017 18:32

#767855

Maybe save the money and time and try the 5th clip..... I went from the 4th to the 5th groove on my 24s before I went with my 29s and it seemed to go good.

1978 KZ650 b-2
700cc Wiseco kit 10 to 1.
1980 KZ750 cam, ape springs, stock clutch/ Barnett springs.
Vance and Hines Header w/ comp baffle and Ape pods, Dyna S and green coils, copper wires.
29MM smooth bores W/ 17.5 pilots, 0-6s and 117.5 main
16/42 gearing X ring chain and alum rear JT sprocket.

Please Log in or Create an account to join the conversation.

SWest
Offline
Sustaining Member
10 22 2014
Posts: 23168
Thanks: 2804

Re: Selecting a jet needle

27 Jul 2017 21:26 - 27 Jul 2017 21:27

#767859

The needles are for fine adjustments. They run best in the center positions. If the next step up on the mains is too rich, you can set the needles down to lean it out in the mid range.
BTW, you have to sync the carbs every time you adjust the needles.
Steve

Z1b1000 1975 Z1b
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882
kzrider.com/forum/2-engine/597654-poser?start=240#704229

Last edit: 27 Jul 2017 21:27 by SWest.

Please Log in or Create an account to join the conversation.

CoreyClough
Offline
User
GPz550 Addiction
Posts: 1094
Thanks: 80

Re: Selecting a jet needle

28 Jul 2017 04:57

#767863

What carbs are these?

'85 GPz550(ZX550-A2)

GPz550 Base Manual --> tinyurl.com/ze5b3qo
GPz550 Supplement Manual --> tinyurl.com/h34d2o6
GPz550.com --> www.nwsca.com/scripts/gpz_forum_2005/default.asp
First Race Win GPz550 --> tinyurl.com/o5y3ftp

Please Log in or Create an account to join the conversation.

KZB2 650
Offline
User
Posts: 1475
Thanks: 265

Re: Selecting a jet needle

28 Jul 2017 07:01

#767868

Check out Jets R us...... they show a 6F4 so I'm "guessing" this is the next step richer but would he start off on the 3rd slot?

1978 KZ650 b-2
700cc Wiseco kit 10 to 1.
1980 KZ750 cam, ape springs, stock clutch/ Barnett springs.
Vance and Hines Header w/ comp baffle and Ape pods, Dyna S and green coils, copper wires.
29MM smooth bores W/ 17.5 pilots, 0-6s and 117.5 main
16/42 gearing X ring chain and alum rear JT sprocket.

Please Log in or Create an account to join the conversation.

SWest
Offline
Sustaining Member
10 22 2014
Posts: 23168
Thanks: 2804

Re: Selecting a jet needle

28 Jul 2017 07:24

#767870

I'd ask them.
Steve

Z1b1000 1975 Z1b
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882
kzrider.com/forum/2-engine/597654-poser?start=240#704229

The following user(s) said Thank You: Buxvan

Please Log in or Create an account to join the conversation.

kyan44
Topic Author
Offline
User
Posts: 38
Thanks: 1

Re: Selecting a jet needle

28 Jul 2017 11:50

#767881

I have a pair of Mikuni VM30. When I open the throttle between 1/4 to 3/4 and I check the spark plugs, It is very lean. I have the clip on the 5th grove, it should make the needle rich. BUt I see no effect

Please Log in or Create an account to join the conversation.