Running a bit lumpy at low revs...

[Sideshow]

Hi all and greetings from Scotland.... !!!

I never thought i'd be on a Busa website looking for some advice or help but needs must !! Anyway, i gotta 2002 Hayabusa (UK spec) which has recently started running a bit "rough" when slowing down (10-20mph - in 1st / 2nd gear) with the throttle shut. I get a quick pulsing/pumping, almost stuttering sensation from the engine which disappears when i open the throttle again. The bike runs perfectly otherwise and has just had an oil change recently but not a spark plug change. I've just come back from a 1200mile round trip to the MotoGP at Silverstone and during the trip down, after two long stints (2 x150miles @ 90-100mph) the bike was really hesitant to start after filling up but this cleared later on (coincidence??). Also towards the end of the trip (just before i made it home) the bike started this "stuttering" (at low speed)whenever i shut the throttle off........any suggestions/advice would be greatly appreciated !!!

Slainte Mhath...

Sideshow

 

[cipher5791]

Maybe your idle is adjusted too low. Try changing the spark plugs also. Won't hurt.

 

[BusaWhipped]

Sync the throttle bodies and adjust the idle.

 

[DaCol.]

Sync the throttle bodies and adjust the idle.

And check plugs first. Do you know how to read them ?

Check Plug Heat Range: If the electrode is wet appearing or dark color, replace with a hotter type. If it is white or glazed, replace with colder one.

Hotter Type NGK CR8E
Standard NGK CR9E
Colder NGK CR10E

Check Plug Gap: I know but these do change with deposits
Plug Gap 0.7mm to 0.8mm

Throttle Bodies: Fast idle (after warming up) 3,500 rpm
normal idle 1,150 (+or- 50 rpm)
Cable Play 2.0 - 4.0mm (0.08-0.16 in)

It really sounds like you just need an Ole Time Tune Up

Hope we can help you

 

[IG.]

There are a couple of pretty simple things to check.

1. Like someone pointed out, if your idle is below 1200 rpm, raise it higher. I personally try to keep it at around 1400 - 1500.

2. There is another small thing which will make your bike idle really crappy - that's if your TPS is off. Switch to dealer mode, and look at the display. The dash should be in the middle as "-C00". If the dash is on the bottom (like this "_C00"), the bike will idle like crap. Adjust it so it stays in the middle. Let us know if you need to know how to do it.

I personally don't think throttle bodies being out of sync can cause what you are describing. The idle will go up and down (i.e. the engine doesn't hold a steady idle rpm), but not stuttering.

 

[KvHotDog4]

Do you have a power commander? Mine was doing the stuttering lunging thing in traffic about 5 - 20 mph. and would be a little hesitant in 6th at 4k rpm. Thought I had a bad map, I reinstalled the new map still did the same thing then I just tried it with out the power commander, everything is good now. I guess it just went bad who knows??? but its runs good now

 

[Peregrine Falcon89]

im not going to thread jack and im not going to start a new one, but my bike has been having a similar issue. idles at 900 RPM and it sometimes has a random stall when downshifting.

whats the easiest way to resync or do that dealer thing that IG was talking about? I think i need to raise mine up a bit..

 

[IG.]

Your idle is definitely low. Up it to at least 1200 rpm. Also, here is what I just PM'ed to another member...


Here is the link to the manual hosting if you don't have one.

Page 4-29 tells how to switch to dealer mode - find the free hanging connector on the left side of the tail section, closer to the battery end (look between the subframe and the plastic) - pretty much put the pin in so you short the contacts on the connector (they call it a special tool). I actually installed a microswitch to make things easier.

Second half of page 4-30 explains how to adjust TPS. It's on the left side of the bike, almost under the throttle body #1. You need to lift the tank.

The procedure is very simple. If you switch to dealer mode, it will show "-C00" on the display. Pay attention to the dash. If it's in the middle, then your TPS is OK. If it's on the bottom (like this "_C00"), or on top, then you need to adjust. Just losen the screws of the TPS, and wiggle it just a tad until the dash is in the middle. Tighten the screws and you are done. Check again.

You don't need to start the engine to do all that. Just turn the key to ON.

 

[Mr Droo]

Hey Colton, we'll adjust your idle before Hayas in the Hills. We're meeting at Greg's house before heading out.

 

[Peregrine Falcon89]

okay sounds good drew.

thanks.