Idles at 1800 when warmed up... why ?

gpwrinkled

Registered
I'm new to Busas. Sold the ZX9R and love this '01.

Here's the idle scenario... when the engine's cold it idles at a normal 1150 rpm. Once it's warmed up it will idle at the normal rpm as long as the clutch is pulled in.. but when in neutral letting the clutch out to idle hands free at a stoplight the rpm bumps immediately to about 1800. Pull the clutch in and the idle drops immediately to normal, even before putting it in gear. This seems bizarre to me. The engine temp is slightly below the half mark, and the only mod to the engine is a Yosh tri-oval titanium pipe and jets. I can't get the straight scoop on what jets were installed as it was done 2 owners ago. The bike has 5k miles on it and accelerates smoothly. Any tips on this are appreciated...

Also - is there an online owner's manual available somewhere?

Many thanks,
Greg
 
Uhhhh, I don't think you would have jets installed... the Busa is fuel injected... no jets bro. Not sure on the idle issue though, I would try turning it down first....
 
Uhhhh, I don't think you would have jets installed...  the Busa is fuel injected... no jets bro.  
The doctor is IN!!

haha...

Wasn't there something about doing that mod that tricks the bike into thinking it's in 5th all the time that had to do with the idle speed?

Just a thought.. maybe somebody else can clear that up.

let it get warmed up good and then adjust the idle with the clutch out... then see what happens..
 
does the idle go up if you turn the handlebars all the way to the left? if so, choke cable is too tight(not really a choke but idle control, check that too).

The 5th gear thing is the TRE mod. You can tell if it works by idling at 2500rpm and pull the clutch, idle should drop few hundred rpms.

Sounds to me like the choke lever is not being pushed back up.
 
You will find when the engine gets hot the sensor which is located above the engine is not getting a true read. Could be that. I would turn your idle down once you are at the 1800 to 1500 and see where you are at when cold.
 
Thanks for the suggestions - I've tried what ya'll have suggested. Turning the handlebars makes no difference so I'm confident it's not a binding situation. Hey Cache, you may be on to something with the TRE theory because when I hold the idle at 2500 and pull the clutch in the idle immediately drops about 600 rpm. I don't know how the TRE is installed but I did find a place on a 3 wire harness under the tank on the left side where two of the 3 wires were spliced into 1. What else should I look for mechanically to verify the TRE is installed ? many thanks, Greg in Mesa, AZ
 
Thanks for the suggestions - I've tried what ya'll have suggested.  Turning the handlebars makes no difference so I'm confident it's not a binding situation.  Hey Cache, you may be on to something with the TRE theory because when I hold the idle at 2500 and pull the clutch in the idle immediately drops about 600 rpm.  I don't know how the TRE is installed but I did find a place on a 3 wire harness under the tank on the left side where two of the 3 wires were spliced into 1.  What else should I look for mechanically to verify the TRE is installed ?  many thanks, Greg in Mesa, AZ
Greg in Mesa, AZ...
hmmm.gif
hope you are enjoying your nice weather!!!

Under the tank, the 3wire connector(white), you say two wires are spliced together. If the pink wire has been altered, then there is either a tre resistor hooked up, or the pink wire is connected directly to the black wire(ground).
If you don't mind having the tre, just adjust your idle at normal operating temperature. 800rpm is a good speed. Just make sure the bike is fully warmed up, and the choke lever is all the way forward.
If you are uncomfortable with the tre mod, and you are good with your hands, rewire that spot so the wires all match in color, ie: pink/pink black/black and forgot what the other one is, but is not used for the tre mod. Hope this helps.
 
Thanks Cache. Now I'll embark on figuring out the pro's and con's of the TRE mod. I'm sure I can find some threads in this forum that cover that, so I hesitate to ask here and bother you guys with rehashing stuff that's already available. If, however, someone knows of a link to a good summary of it I'd appreciate it.

Cheers - and thanks again,
Greg
 
Thanks Cache.  Now I'll embark on figuring out the pro's and con's of the TRE mod.  I'm sure I can find some threads in this forum that cover that, so I hesitate to ask here and bother you guys with rehashing stuff that's already available.  If, however, someone knows of a link to a good summary of it I'd appreciate it.

Cheers - and thanks again,
Greg
You can also make a swith to shut the TRE on and off.
 
).
If you don't mind having the tre, just adjust your idle at normal operating temperature. 800rpm is a good speed. Just make sure the bike is fully warmed up, and the choke lever is all the way forward.
I'm sorry, but I have to disagree with you about the 800rpm on idling Cache. A good idle should be anywhere from 1100 to 1300 rpm. I have found and have heard from many others that idling below 1000rpm will cause the bike to inadvertantly shut down when running at high speeds and quickly pulling in the clutch. Just my .02



Brian
 
Take this bike to someone that knows what a stutter box is. It sounds like someone tried to install one incorrectly. This is a box that kills 2 spark plugs until the clutch is let go. unfortunantly they don't work the same on 4 coil bikes. They are designed for ease of launching bikes at the draag strip. There isn't a lot that is wired to the clutch start safety switch from suzuki.
 
Back
Top