The Yamaha Road Star Warrior Forum

I think there was someone else here with off-idle sputtering but it was posted 4 years ago. 

It sounds like it's sputter out of the front left side of the tank:

My first impression is was that there's bubbles in the gas line because I just rerouted the fuel line:

I put in the Big Shot with quiet baffles and my old map was Pro Pipe with no baffle.  So I thought I was running rich and I just bumped down the PCIII a notch for the low and middle.  I checked the plugs and they were black but it ran ok until I could get a custom map.  (I've been waiting for a Twinmax for 3 weeks and it finally is coming this Saturday.  I have been messing with the brass throttle body sync screw.  Hissing sound is loud.)

How do I make this sputter less until I can take it to the Dyno place? 

I'm guessing it's either:

A.) the new exhaust

B.) messing with throttle body sync

C.) the new fuel line

D.) that check valve at the end of the gas tank vent

E.) Leaning out the external PCIII

What do yall think? 

 What do I think? I think I'm in love with the girl in your post. lol

My bike loses it's mind at 1800 to 1900 rpm. It either backfires or

stumbles. I'm just practicing ignoring it since I can't figure out

what's causing it. 

Got the same thing here. It sounds like it's backfiring through the throttle-body. 

HOLY CRAP!!!!!

 Mine does that too.  I've been messing with the PCIII in that range for some months now and can't figure it out.  It usually happens when I upshift (I roll off, shift, then reengage the clutch and roll on - then it sputters, normally around the 1750-1900 range).  If I'm accellerating like a bat out of hell, then I never have the problem because I'm upshifting at 3500 RPM and it never gets to drop as low as 2000 RPM.

 Any suggestions out there?

 and yes, it's out the throttlebodies.  It began after I installed my VBAK, so I'm wondering if that's a factor (disclaimer: I'm not blaming anything on Churchkey!  Keep up the good work on your product.)

SWODude:

 Any suggestions out there?

 

Fresh injectors, synced TBs, fresh fuel, and a good map. My bike sounds like a kitten at 1900. A bright red 600 pound kitten.

What are your PCIII values for the 1750 and 2000 rows?  I have the issue between 2% and 10%.

 Exactly,

 Right. The bike runs perfectly EXCEPT at low or no throttle and 1800/1900 rpm.

I have cleaned, adjusted etc.till I'm blue in the face.

Paid $250 for another custom map.

Paid another $120 to let the dealer screw around with it. Finally left the custom map on

the pcIII but bumped the ecu 3 points.

Believe it or not, this helped quite a bit.

Correct me if I'm wrong, but that seems to indicate a lean condition at that rpm only. 

I still get occasional exhaust pops when upshifting at low throttle or a puff/stumble  

from the throttle body off idle.

This is definately NOT because of the Vbak.

I've had the Vbak for three years and these problems started just in the last year. 

SWODude:

What are your PCIII values for the 1750 and 2000 rows?  I have the issue between 2% and 10%.

Mostly... +10s.   I use Jody's map with some small changes.

It would be helpful if you would all compare your mods and recall status since some gallery pages don't exist. For example, how many have this exact trouble and:

• Have re-routed their fuel lines or changed to different dry breaks.
• Have not done the TPS recall.
• Have not done the CPS recall.
• Have not installed a PC3.
• Have installed a PC3 but not dynotuned?
• ?etc.

The most common trouble here is the TPS or CPS however most everyone knows about these so comparing your mods and recalls could point the way to the light.

Arizona Warrior:

It would be helpful if you would all compare your mods and recall status since some gallery pages don't exist. For example, how many have this exact trouble and:

• Have re-routed their fuel lines or changed to different dry breaks.NO
• Have not done the TPS recall.DONE
• Have not done the CPS recall.DONE
• Have not installed a PC3.INSTALLED
• Have installed a PC3 but not dynotuned?CUSTOM MAP
  
• ?etc.

The most common trouble here is the TPS or CPS however most everyone knows about these so comparing your mods and recalls could point the way to the light.

I think the problem started shortly AFTER the cps recall was done. 

 

patriotins:

 What do I think? I think I'm in love with the girl in your post. lol

Dude, know you not Jessica Alba?

You haven't seen Sin City?  It's da bomb.

Anyhow,  yeah when I'm accelerating and I suddenly pull in the clutch, the engine sometimes dies because the rpm dips too low.  Weird huh?!

I have a stock 07. I have had the same probem since I bought the bike new. It happens when I am at 1900-2000 RPM which just so happens to coincide with the on-off throttle position. One hair forward and the throttle is off and decelerating and one hair back and the throttle is open and accelerating. There is no problem on either side of this on-off threshold. the sputtering hapens when I try to maintain a low, steady neutral throttle postion. I assume its the TPS but havent done anything about it.

Arizona Warrior:

It would be helpful if you would all compare your mods and recall status since some gallery pages don't exist. For example, how many have this exact trouble and:

• Have re-routed their fuel lines or changed to different dry breaks.
• Have not done the TPS recall.
• Have not done the CPS recall.
• Have not installed a PC3.
• Have installed a PC3 but not dynotuned?
• ?etc.

The most common trouble here is the TPS or CPS however most everyone knows about these so comparing your mods and recalls could point the way to the light.

 

Okay so that was a bad idea on my part.  Now I have even more questions. 

By any wild chance are some of you using the same map from Dynojet's website?  Said another way, I wonder if the air:fuel at 2000 rpm in a series of maps has faulty data? 

Considering the basics, I wonder if everyone has set the zero throttle position in the PC3 to warm idle 900rpm, and I wonder if all maps start at 500rpm to cover the warm idle 900rpm. 

Well hopefully you guys can post a bunch of details about PC3's and recalls and maybe someone will notice the common link.  It has to be there.