Major Stutter 2000-4000rpm

[MrGixer]

First of all Hi everyone!!

I am haveing a bit of trouble with my Busa. I noticed a while back that my Busa had a stutter between 2000-4000rpm, this was with the bike totally standard.

I won a few goodies on Ebay so now the bike has a Full Akro Evo system and a PCII fitted. I also have done the small airbox mod and removed the PAIR valve. I also have a smart TRE fitted. I was hoping that once a custom map was completed that this problem would have gone, but it hasnt!!

The bike runs fine once past 4000rpm which is a bit odd. The guy at the dyno centre said he could feel it (I had told him there was a problem before he started working on it) but no matter what he did to the fuel/air ratio the stutter would not go! I have looked at the fuel/air ratio graph from the dyno printout and it looks pretty good to me.

I have pulled the fuel pump apart and ditched a few filters and cleaned the others, though I will be checking the injector ones a bit closer I think. I have also synched the throttle bodies but they were only out a smidge and nothing changed after doing this. Sparks are iridium ones and have only done 4000miles so I woulda thought they be ok but they are another item i will look at.

I did use the search function but could not find a conclusive answer as noone ever seemed to reply with how they actually solved the problem in the end lol!!

Its almost unrideable on small/part throttle though. Makes riding through town a bit annoying. Any help appreciated!!

Many thanks

Paul

 

[cache]

First of all Hi everyone!!

I am haveing a bit of trouble with my Busa.  I noticed a while back that my Busa had a stutter between 2000-4000rpm, this was with the bike totally standard.  

I won a few goodies on Ebay so now the bike has a Full Akro Evo system and a PCII fitted.  I also have done the small airbox mod and removed the PAIR valve.  I also have a smart TRE fitted.  I was hoping that once a custom map was completed that this problem would have gone, but it hasnt!!

The bike runs fine once past 4000rpm which is a bit odd.  The guy at the dyno centre said he could feel it (I had told him there was a problem before he started working on it) but no matter what he did to the fuel/air ratio the stutter would not go!  I have looked at the fuel/air ratio graph from the dyno printout and it looks pretty good to me.

I have pulled the fuel pump apart and ditched a few filters and cleaned the others, though I will be checking the injector ones a bit closer I think.  I have also synched the throttle bodies but they were only out a smidge and nothing changed after doing this.  Sparks are iridium ones and have only done 4000miles so I woulda thought they be ok but they are another item i will look at.

I did use the search function but could not find a conclusive answer as noone ever seemed to reply with how they actually solved the problem in the end lol!!

Its almost unrideable on small/part throttle though.  Makes riding through town a bit annoying.  Any help appreciated!!

Many thanks

Paul

remove the TRE and have the PCII remapped.

I did this, and it was night&day difference.

 

[cache]

and welcome to "THE" board.

 

[The Big Red One]

First of all Hi everyone!!

I am haveing a bit of trouble with my Busa.  I noticed a while back that my Busa had a stutter between 2000-4000rpm, this was with the bike totally standard.  

I won a few goodies on Ebay so now the bike has a Full Akro Evo system and a PCII fitted.  I also have done the small airbox mod and removed the PAIR valve.  I also have a smart TRE fitted.  I was hoping that once a custom map was completed that this problem would have gone, but it hasnt!!

The bike runs fine once past 4000rpm which is a bit odd.  The guy at the dyno centre said he could feel it (I had told him there was a problem before he started working on it) but no matter what he did to the fuel/air ratio the stutter would not go!  I have looked at the fuel/air ratio graph from the dyno printout and it looks pretty good to me.

I have pulled the fuel pump apart and ditched a few filters and cleaned the others, though I will be checking the injector ones a bit closer I think.  I have also synched the throttle bodies but they were only out a smidge and nothing changed after doing this.  Sparks are iridium ones and have only done 4000miles so I woulda thought they be ok but they are another item i will look at.

I did use the search function but could not find a conclusive answer as noone ever seemed to reply with how they actually solved the problem in the end lol!!

Its almost unrideable on small/part throttle though.  Makes riding through town a bit annoying.  Any help appreciated!!

Many thanks

Paul

Like Cache said it sounds like the TRE....I had similair probs with mine.

 

[MrGixer]

Doh! I just payed £150 for a custom map too lol. Though they did say come back if it was really bad so I might pull it out and go back.

I did try pulling it out when the bike was standard and it didn't stop it, but like u guys said maybe if its re-mapped it will! will let you know how it goes.

Thanks for the advice guys.

 

[MrGixer]

Ok, just back from the dyno centre and we still cant gte rid of it

I removed the TRE and rode down there. There was no difference which I would have thought there would be. Had a play on the dyno again and what ever they did it would not go.

The stutter only happens when on part throttle (i.e. just a really small amount) as soon as u apply a little more to accelerate it goes silky smooth!! It also is worse when under load, i.e. if I have a pillion it is amplified.

One thing I forgot to mention was when I was synching the throttle bodies the other day I was listening to it whilst it was on tickover and number one cylinder seemed to cut out and spit at me then run again? it sounded like it lost its spark for a second. Anyone had any problem with the iridium plugs? they lasted great on my old bike.

 

[CorrodedAlien]

I had/have the same issue. The unfortunate thing is it is most apparent at highway speedin 6th. That is 90ish mph around my area. An after market can or full system w/ map will clean un the "mid rev stutter"

I had the same issue on my old ST1100, a set of 2bros cans did away w/ it. I asked around a lot and the answer I got had to do w/ the mid pipe/baffle messed w/ the mid range.

 

[jwcfbd]

Have you done a dyno run on it?  What kind or power are you pulling and what does the power curve look like?  The reason I ask is because of the picture below.  This is what mine looked liked like when I found out that the cam chain was off by a tooth.  The two lines are a before and after shot. As you can see it had a major stumble point and a major lack of power.



<!--EDIT|jwcfbd
Reason for Edit: None given...|1121430575 -->

 

[cache]

good call jim.

 

[MrGixer]

Thanks Jim I did read about your problem already when I was using the search function.

My power curve is silky smooth and so is my torque curve. Even with the Dyno being over 100f inside the bike still put out just over 170hp!! I reckon it will be good for 174hp if the air was cooler.

 

[carbusa68]

First of all Hi everyone!!

I am haveing a bit of trouble with my Busa.  I noticed a while back that my Busa had a stutter between 2000-4000rpm, this was with the bike totally standard.  

I won a few goodies on Ebay so now the bike has a Full Akro Evo system and a PCII fitted.  I also have done the small airbox mod and removed the PAIR valve.  I also have a smart TRE fitted.  I was hoping that once a custom map was completed that this problem would have gone, but it hasnt!!

The bike runs fine once past 4000rpm which is a bit odd.  The guy at the dyno centre said he could feel it (I had told him there was a problem before he started working on it) but no matter what he did to the fuel/air ratio the stutter would not go!  I have looked at the fuel/air ratio graph from the dyno printout and it looks pretty good to me.

I have pulled the fuel pump apart and ditched a few filters and cleaned the others, though I will be checking the injector ones a bit closer I think.  I have also synched the throttle bodies but they were only out a smidge and nothing changed after doing this.  Sparks are iridium ones and have only done 4000miles so I woulda thought they be ok but they are another item i will look at.

I did use the search function but could not find a conclusive answer as noone ever seemed to reply with how they actually solved the problem in the end lol!!

Its almost unrideable on small/part throttle though.  Makes riding through town a bit annoying.  Any help appreciated!!

Many thanks

Paul

My stocker did the same thing 2000-3000 rpm loaded and here was what helped to make it very very acceptable but not perfect during all conditions.
I set the idle speed to 1150 and then performed the TPS adjustment by jumping the dealer connector and obtaining the center bar -COO on the clock which is the Suzuki method. Mine was right on the center bar...but..I could roll the throttle a bit and it would stay on the center bar (the range that I rolled the throttle was the range that it chugged, chain slapped like mad on the street). I loosened and played with the TPS and found that the center bar has "room" so as an experiment I advanced the TPS so that when the throttle is opened .010 inch or .254 mm it will jump to the upper bar on the clock. My TPS voltage on the signal return wire at the switch when done was 1.18 volts and I used feeler gauges in the fast idle cam area to obtain measurement.
It cleaned up the problem for me.
Your tuner may not be addressing the low throttle position, low rpm area of the map since most Commander maps from Dyno Jet don't make changes below 2500 on any bike. It's hard to simulate the street on a dyno that low... and under many conditions perfect A/F ratios do not make a perfect running engine.
I don't see any device on the busa that determines engine load? On automotive you would generally have a MAP or MAF that would input with the TPS, rpm, road speed, gear range, etc. to determine engine load...... so..... without this "digit" in the equation on a small engine with cam overlap, big head ports, flowing exhaust and the horsepower to cc ratio that is like a 5.0 liter naturally aspirated car motor making 600 hp that meets emission standards!!!! we may have a glitch somewhere, especially down low.

Hope this at least helps as a conclusive answer. Good Luck and I would like to hear your results good or bad.
Collin

 

[MrGixer]

So by the sound of what you have just said you have richened things slightly by adjusting the TPS.

I will double check the setting of the TPS and that it hasnt come loose. By moving this though it will effect the whole rev range so I am a little wary of doing that.

I think I will maybe try adding 5% extra fuel to the first 5% and 10% throttle movements at low rpm and see what happens first, that should be doing a similar thing to what moveing the TPS did! I will keep you updated as to if this helps!

Many thanks again