High Idle on DFI

Hi z1300 Fans

I have a 1300 DFI engine no starting KZT30AE The bike was custom built for me but after not having the bike for very long I seem to be running into an annoying issue the engine and fuel injection including all management systems are standard

The problem is when the bike is started cold it idles great at about 500rpm then as it starts to get warmer the idling will pick up to 1500rpm and not come back down from there. Then when you ride the bike and stop at a stop street or traffic light the bike will idle at 2000rpm making it difficult to select 1st gear without it obviously grating, the other problem is obviously the bike will be slightly over operating temp until it cools down again with a bit of a run and air flowing over the radiator until our next stop street or traffic light encounter

Now a couple of things that may help you guys with diagnoses is :

1)The bike runs a 3 into 1 std straight through exhaust system no boxes or baffles ( you got to have the music)
2)The Bone head that built the bike for me didn't bother to put a new air filter in until I did a couple of weeks ago
3)It was also suggested to me that I run the bike on a 25to1 ratio 2stroke mix while the engine is running itself in I have since obviously stoped this recently as the bike has done over 2000km since I got it and now runs just on unleaded fuel since doing this the rpm has picked up to 2000rpm idle
4)When the bike was in the process of being built I did raise the question to the builder of my concern because the engine was revving so high on idle 1000 to 1200 rpm after the builder did some fault finding he sais he found one of the circuit lines in the board had blown and that he had it repaired and that the idling was then better unfortunately the bike seems to be idling high again

Please send me your advice on how to correct this problem ! it would be greatly appreciated

Thank you

Chad Wilson

Chad:

In order for us to help you it would be helpful if you provided more information. Saying an engine was built does not provide enough information to assist you.......

1: Model year.
2: What was done to the engine.
3: Saying that a circuit was repaired in the DFI controller is a little concerning, and how he repaired it.
4: An open exhaust system will cause the engine to behave differently. Do you have the factory mufflers to put back on it?
5: Having a "25:1 two stroke ratio" are you saying you mixed the fuel?
6: Have you checked for Vacuum leaks?

T.

Hi T

Thanks for getting back to me its appreciated !

I will try to answer your questions accordingly

1)Model year 1984 according to licence registration paper but after my local Kawasaki shop did some research for them to order me workshop manuals it looks like the chassis is a 1979 according to chassis no ZGT30A000838 and engine may be 1985 according to Engine no KZT30AE020476

2)As far as I know the engine was rebuilt some new parts some reconditioned parts some second hand parts I would have to go back in past emails to check what parts were which

3)According to him he had a mate put the circuit board under a magnifying light and do the soldering weld repair it was that small of a repair (not sure if I believe that bull)

4)I do have the mufflers he built for the bike but not the standard factory mufflers I would really like to keep the exhausts open though as it sounds really good without mufflers

5)Yes the fuel was premixed in the fuel tank 25:1

6)No I have not checked for vacuum leaks as I have only recently received the bike from the builder and have not purchased any tools as such yet and obviously didn't think I needed too so soon

I hope these answers will help you with your diagnosis

Thanks

Chad

Hello there
I had the same issue with one of my KZ1300 1981, it was as stupid as the throttle cable being compressed under the tank not fully releasing the detent once the bike was warm, Took the tank off the bike and re routed the throttle cable in the right passage way and that was it.
I cannot guaranty that it will be same for you but its worn fiddling around with the throttle cable, now since you have a DFI it also an issue with your mother board, I once consider buying one of the Injection Z1300 but my mechanic told me that once the mother board is acting up its better to change it and its costly....
I wish you good luck as those bikes can be very demanding and after going through four of them I finally gave up could not afford the expenses and time involved in figuring it out, my heart still beats for these Bitchy bikes but finally converted to a 2010 VRF/Interceptor 1200 with all the modern components, ABS brake and no mor issue at cold start and I am thrilled about it....
Good luck to you

What the other guys said with the throttle cable routing & making sure the throttle mechanism returns to it's stop, also checking you have freeplay on the cables & checking for air leaks. Also making sure the fast idle lever is shutting off fully. I've never heard of adding 2-stroke oil to the fuel to aid running in, that would have the effect of weakening the fuel mixture as well as introducing unwanted carbon into the combustion chamber & fouling the plugs.
On the air leak front I found that the hose clips clamping the rubber manifold rubbers to the throttle bodies need to be tighter than you think as the rubber stiffens with age.
Also check you haven't got any air leaks on the vacuum pipe to the fuel pressure regulator.

Phil wrote: What the other guys said with the throttle cable routing & making sure the throttle mechanism returns to it's stop, also checking you have freeplay on the cables & checking for air leaks. Also making sure the fast idle lever is shutting off fully. I've never heard of adding 2-stroke oil to the fuel to aid running in, that would have the effect of weakening the fuel mixture as well as introducing unwanted carbon into the combustion chamber & fouling the plugs.
On the air leak front I found that the hose clips clamping the rubber manifold rubbers to the throttle bodies need to be tighter than you think as the rubber stiffens with age.
Also check you haven't got any air leaks on the vacuum pipe to the fuel pressure regulator.

Ditto! :woohoo: