Hayabusa idle increased on it's own?

cq90stang

cq90stang

Registered
I've had this bike since about 14,000 miles. Currently has 26789 miles on it. After letting the bike sit for about a week I drive it to work today and it is idling about 1700 rpms (usually idles at 1400, ever since I've owned it). Below is a list of Mods (not all but some that may have an effect on the idle issue)

Mods that were on bike when I purchased it:
Yoshi RS3 exhaust
1 inch bar risers
Lowered 3 inches

Mods I put on bike:
grips
clutch and brake levers
clutch and brake lever covers
HID lights
K&N air filter
new battery installed september 2012 (YUASA brand YT12A-BS)

Last service was done at Suzuki dealer, had them inspect/adjust valves. I did the new plugs and the air filter when I got it back. It was serviced either in june or july of 2012. had somewhere around 23000-24000 miles on it. The motorcycle always idled about 1400 rpms since I've owned it. I live in Florida so I don't use the fast idle lever (and made sure it wasn't on). and there is slack on the throttle itself (so it's not an improperly adjusted throttle cable). All mods were on bike before I started having this issue.

When bike is first started (no fast idle) it idles at about 900-1000 rpms (no fast idle), after the bike warms up it idles at 1700 rpm's? Ive done nothing mechanical wise to the bike since the last time I rode it and it idled at 1400 rpms. So just curious as to why the idle would increase. The bike doesn't search at idle...just gained rpm's at idle some how.

Would the valves being adjusted tighten the motor that much to cause a 200 rpm variance after they've been worked in a little?
Bad or going bad TPS (no lights lit up on dash)?

any help appreciated
 
How does the bike run, otherwise? Maybe something is causing the fuel to lean out or perhaps a vacuum leak? Have you tried to readjust the idle? My busa idles all day long a 1000 RPM.
 
SoCal Blur said:
How does the bike run, otherwise? Maybe something is causing the fuel to lean out or perhaps a vacuum leak? Have you tried to readjust the idle? My busa idles all day long a 1000 RPM.
Click to expand...


+1 on adjusting the idle.. when the engine is warm enough adjust the idle around 1200-1250.. that hopefully take care of the problem.. in case if you don't know where the idle screw is on gen1, take the seat off unscrew the upper screw of the gas tank and lift the tank, the idle screw is on upper right..
 
It is possible that they did a TB sync during the service... could have raised the idle that way... Another method of adjusting the idle is simply pulling the right side fairing away from the takn, you can reach the horizontal adjustment screw (phillps) with a long screw driver - recommend that after you make any adjustments, you rev the throttle to see where it settles back out.
 
My Gen I does this about once a year. Just raises (or lowers) for no apparent reson. I just turn the idle screw and it fixes the issue.

Make the adjustment after a ride, not before. :thumbsup:
 
The first thing I thought of was a lean condition but Im more familiar with carburetor systems than FI. I would make sure all your intake boots are tight and on all the way before you start adjusting the idle just to be on the safe side.
 
SoCal Blur said:
How does the bike run, otherwise? Maybe something is causing the fuel to lean out or perhaps a vacuum leak? Have you tried to readjust the idle? My busa idles all day long a 1000 RPM.
Click to expand...

The bike runs as normal as the day I got it...just a higher idle. Didn't get a chance to adjust the idle because I got off work around 1 am yesterday so I just parked it, and hit the forum up.
 
shawnski said:
+1 on adjusting the idle.. when the engine is warm enough adjust the idle around 1200-1250.. that hopefully take care of the problem.. in case if you don't know where the idle screw is on gen1, take the seat off unscrew the upper screw of the gas tank and lift the tank, the idle screw is on upper right..
Click to expand...

Thanks, I knew where it was (but it will serve for a reference for those that stumble on this thread who don't know where it is)...just never adjusted it before because the 1400 rpm idle speed didn't bother me, 1800 rpms does bother me
 
MC MUSTANG said:
It is possible that they did a TB sync during the service... could have raised the idle that way... Another method of adjusting the idle is simply pulling the right side fairing away from the takn, you can reach the horizontal adjustment screw (phillps) with a long screw driver - recommend that after you make any adjustments, you rev the throttle to see where it settles back out.
Click to expand...

Not really sure what all they did in the service. I paid 585 (if I remember right) for the valve adjustment. They tried selling me new plugs at $16 bucks a pop and a new air filter at $80, I declined both as I told them I could get the plugs at the auto parts store for $4.00 a plug and a total of $16 (instead of $64 for plugs) and I told them there was no way I was paying $80 for a paper air filter when I could get a K&N filter for the same price. The bike didn't get done when it was supposed to be done, and I also had them fix the 2 front brake calipers that were dragging. At first they tried saying the brakes weren't covered in the warranty I have, but then I went down there and told them that Brake Pads aren't covered, but that calipers should be and talked with the service manager, and he said they would send it off to the warranty company and see if they accept. by the time it all was over, the warranty company accepted the claim for the brakes, so I ended up getting:

2 new front calipers
All new brake Pads (because it was the calipers that killed the brakes)
A new Brake Master cylinder

I got free plugs and air filter(because the original service writer didn't send it off to warranty first, I guess for the added hassle I had to go thru)

If I remember right the bill for brakes alone was around 1400 dollars. thank GOD for warranties :laugh:


I only asked for a valve adjustment, so I don't know if they would have adjusted anything else along with the valve adjustment
 
voodoolord said:
The first thing I thought of was a lean condition but Im more familiar with carburetor systems than FI. I would make sure all your intake boots are tight and on all the way before you start adjusting the idle just to be on the safe side.
Click to expand...

Thanks, I did a check on everything. boots were tight on the airbox.
 
So before I went to work today I worked on the busa. Propped the tank up, pulled out the air filter to check just in case. It was clean, so not an Air filter issue. The boots are definitely seated from the airbox...because I had to pull the whole airbox off because like an idiot I dropped a screw that secures the filter to the box and it went down below the box...lol :banghead:

Started the bike up let it idle (cold idle 1300) till it warmed up and got nice and warm, right around 20-25 minutes. While it was warming up I was loosening bolts, Anyways the bike was warm enough that the frame was noticeably hot and the temp gauge showing about 1/2 on the gauge. By this time it was idling about 1700-1800 rpm's. Shut the bike off and checked the air filter, put it back on. fired up the bike again and adjusted the idle with the set screw. Didn't take anymore than about 1/4 turn to adjust the idle. Blipped the throttle 4-5 times let it settle. let it idle for 4 more minutes and blipped the throttle to make sure that everything was good. Shut the bike off, and put it back together. At this time my bike idles some where in the neighborhood of 1200 rpms when warmed up and about 1000 rpms when first started.

Rode it into work (keep in mind I weigh about 160 lbs) I was running close to being late to work from doing the work on the bike. Take out the driveway and click the bike into second, guess I gave it a little more throttle than the shinko stealth rear can handle, dry pavement second gear at 40 mph, just twist the throttle and break traction, 3rd gear 70 miles per hour twist the wrist and break traction...no clutching, and I'm not hammering on the throttle just gradually twisting it further and further till about 1/2 a twist of throttle (I only post this as SoCal Blur asked how my bike was running). I haven't rode anybody else's hayabusa and this is the only Hayabusa I have been on, so no reference as to how other busa's run/ feel other than the one I own.

Came back from work tonight, and all is still well with the idle so hopefully this cured the bike of the high idle.
 
Also while I was digging around for the screw I notice a line that was plugged with a screw (I imagine it's been that way since before I owned it) and a black cylindrical object with a nipple on it (I'm presuming that the plugged hose, which isn't long enough to connect to the cylindrical object with the nipple, used to be connected). I tried looking for the items in my clymer manual, I can find a diagram for the throttle bodies that shows the hose...but not where it connects. I cannot find any reference to the cylindrical object with the nipple on it.

Is there any reason these would be disconnected...some type of mod...or just someone rigged it. Well when I went to get the pics, I figured I'd adjust the slack in the throtle cables, so now that is done to.

Thanks for all your help with the previous matter and any info you can give me with the hose (that is plugged) and the cylindrical object with a nipple on it. Both items are on the left side of bike. Hose is coneected to throttle body and the cylindrical object is on the same side under the airbox.

IMAG0911.jpg


IMAG0912.jpg
 
cq90stang said:
Also while I was digging around for the screw I notice a line that was plugged with a screw (I imagine it's been that way since before I owned it)
Click to expand...

looks like a "marble mod" done using a screw...cures decel pop which may occur when running a full exhaust with stock tune
 
kromdom said:
looks like a "marble mod" done using a screw...cures decel pop which may occur when running a full exhaust with stock tune
Click to expand...

Thanks for the reply, not so sure it is a marble mod when I look at this thread, but I've been wrong brefore.

https://www.hayabusa.org/forum/general-bike-related-topics/139166-marble-mod.html

The line on my bike is on the Left side of motor and is small (marble wouldn't fit in it), and the other black object with the nipple on it appears to be apx the same diameter to couple a hose to as the one that is blocked off by the screw (which also just happens to be too short to plug in. On the pics I see of the marble mod, they are doing it on the right side of bike in the tube that is closest to the frame, which is opposite from where the components I am talking about are.
 
Last edited:
Hello I recently joined this forum and I have been reading a lot of threads and I noticed your question about the blocked hoses could it possibly be the valve pair block off mods im not saying that is what it is but from what I have read on here it could very well be that mod hopefully someone with more knowledge will be able to say for sure
 
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