High Idle Speed - cant figure it out!
- H-Bomb
-
Topic Author
- Offline
- User
-

Registered
- Posts: 16
- Thanks: 0
High Idle Speed - cant figure it out!
25 Sep 2015 03:10
Hi all,
My KZ750Twin starts and runs perfectly - apart from one thing...when she starts she runs at a normal idle, but once warmed up the idle rises to rest at circa 3000 rpm.
I have added pods - but it was in fact doing this before I made the change.
I am assuming I have an air leak somewhere so have bought some starter fluid that I am being very sheepish with -thing is if she is already at 3000 rpm its hard to know if it goes higher from just starter fluid - is this problem likely to be down stream of the engine block around the carbs? of the engine or could it be near the front of the engine too - say exhaust or gasket or something leak or something.
Could I tune it out by adjusting the carbs? I thought it unlikely to be that given she idles fine cold, but then goes high when warmed up..
All feedback welcome. FYI I could not find any info in the manual to help sort this out.
Cheers!
My KZ750Twin starts and runs perfectly - apart from one thing...when she starts she runs at a normal idle, but once warmed up the idle rises to rest at circa 3000 rpm.
I have added pods - but it was in fact doing this before I made the change.
I am assuming I have an air leak somewhere so have bought some starter fluid that I am being very sheepish with -thing is if she is already at 3000 rpm its hard to know if it goes higher from just starter fluid - is this problem likely to be down stream of the engine block around the carbs? of the engine or could it be near the front of the engine too - say exhaust or gasket or something leak or something.
Could I tune it out by adjusting the carbs? I thought it unlikely to be that given she idles fine cold, but then goes high when warmed up..
All feedback welcome. FYI I could not find any info in the manual to help sort this out.
Cheers!
Please Log in or Create an account to join the conversation.
- martin_csr
-
- Offline
- User
-

Registered
- Posts: 7993
- Thanks: 1648
Re: High Idle Speed - cant figure it out!
25 Sep 2015 03:22
When starting the bike cold, are you using the choke & are you touching the throttle grip?
I would get it running right first with the airbox --- adding the pod filters kinda complicates matters. Troubleshooting this sort of thing isn't my forte, but you may need to rejet the carburetors & do some tuning for the pods.
I would get it running right first with the airbox --- adding the pod filters kinda complicates matters. Troubleshooting this sort of thing isn't my forte, but you may need to rejet the carburetors & do some tuning for the pods.
Please Log in or Create an account to join the conversation.
- H-Bomb
-
Topic Author
- Offline
- User
-

Registered
- Posts: 16
- Thanks: 0
Re: High Idle Speed - cant figure it out!
25 Sep 2015 03:26
Thanks martin.
I am just using the choke, no throttle needed when starting cold.
I am just using the choke, no throttle needed when starting cold.
Please Log in or Create an account to join the conversation.
- Nessism
-
- Away
- Sustaining Member
-

Registered
- Posts: 8205
- Thanks: 3577
Re: High Idle Speed - cant figure it out!
25 Sep 2015 03:33
Pods require major rejetting. Not just upping the main. If anyone sells a jet kit you should consider buying it. Dynojet for example.
A high idle suggests a vacuum leak. The carb boots are often the culprit. A high idle could also be caused by poor carb sync or a lean mixture at idle. I'd go through the carbs and replace all the various O-rings, install a jet kit to compensate for the pods, vacuum sync, and set the pilot screws for the highest idle methodology.
Good luck,
A high idle suggests a vacuum leak. The carb boots are often the culprit. A high idle could also be caused by poor carb sync or a lean mixture at idle. I'd go through the carbs and replace all the various O-rings, install a jet kit to compensate for the pods, vacuum sync, and set the pilot screws for the highest idle methodology.
Good luck,
Ed
Carb O-ring Kits : www.kzrider.com/forum/14-vendor-forum/62...rburetor-o-ring-kits
www.kzrider.com/forum/faq-wiki/618026-new-owner-things-to-know
1981 KZ750E2
www.kzrider.com/forum/11-projects/604901...z750e-project-thread
Carb O-ring Kits : www.kzrider.com/forum/14-vendor-forum/62...rburetor-o-ring-kits
www.kzrider.com/forum/faq-wiki/618026-new-owner-things-to-know
1981 KZ750E2
www.kzrider.com/forum/11-projects/604901...z750e-project-thread
The following user(s) said Thank You: H-Bomb
Please Log in or Create an account to join the conversation.
- Patton
-
- Offline
- KZr Legend
-

Registered
- Posts: 18564
- Thanks: 2103
Re: High Idle Speed - cant figure it out!
25 Sep 2015 04:00
Perhaps the carb butterflies could be adjusted and synced toward slightly more closed at idle position.
The following links should contain a downloadable manual -- free -- which will hopefully include some helpful info as to carb adjusting on the KZ750 twins.
kz750twins.com/?p=15
biquetoast.com/cgi-bin/750ManualList.cgi
Good Fortune!
The following links should contain a downloadable manual -- free -- which will hopefully include some helpful info as to carb adjusting on the KZ750 twins.
kz750twins.com/?p=15
biquetoast.com/cgi-bin/750ManualList.cgi
Good Fortune!
1973 Z1
KZ900 LTD
KZ900 LTD
The following user(s) said Thank You: H-Bomb
Please Log in or Create an account to join the conversation.
Moderators: Street Fighter LTD
