Engine studder below 2000 RPM

[hinglby]

Ok, short update...

Wasted $177 on new O2 sensor and $12 on Seafoam. Still stumbling! The K&N filter is cleaned regularly, but to eliminate I cleaned it again yesterday.

I can't afford to keep shotgunning parts, the only remaining items are expensive. I know the only reputable shop and the owner is very knowledgeable. He is stumped as well. This is one of those issues that makes me ride ever harder, preying for a hard failure.

Any more thoughts?

 

[Willtill]

Ok, short update...

Wasted $177 on new O2 sensor and $12 on Seafoam. Still stumbling! The K&N filter is cleaned regularly, but to eliminate I cleaned it again yesterday.

I can't afford to keep shotgunning parts, the only remaining items are expensive. I know the only reputable shop and the owner is very knowledgeable. He is stumped as well. This is one of those issues that makes me ride ever harder, preying for a hard failure.

Any more thoughts?

Seafoam is $7.99 at Walfart (Walmart). Just for future reference.

Have you though about getting the ECU reflashed by the dealer; with the original Triumph maps?

Fuel pump going tits up?

I do feel your pain. It is maddening to go through all of this troubleshooting, only to arrive at the same result.

 

[pjsmithres]

We are all trying to help.

After re-reading the first post, I'll offer, that a friend with a rocket had a fuel pump problem with a similar but more pronounced problem.

After a long diagnosis, heartbreak of replacing things, the dealer found an O-ring on the fuel pump connection had begun to fail and the bike didn't get "ENOUGH" fuel unless the pump was "in high gear". Not sure which O-ring, but a check of it can be done for labor. Check the tank (open) with a flashlight. Have the fuel level below the pump.
It was found with the tank half full, that a stream (like a squirt gun) pumped fuel back into the tank.

Since the pump is IN the tank this problem may go un-noticed for a while.

Flashlight and a look is free?

 

[barbagris]

The symptoms cam on suddenly but intermittent. She would run fine for a week or two then the symptoms came on suddenly with the same severity every time. Now its constant.

Not sure if it's relevant but I've found that when the ambient outside temps are hovering around a certain temperature the ECU seems to jump from lean to rich (or something) instead of gradually adjusting. And I get a sort of "carb' poor pickup" stutter. With the Stock ECU and tune only this was about 20ºC on mine. Changed the tune and the temp threshold moved to closer to 25ºC. Drove me crazy one spring where temps were rising and falling across the threshold daily. The PC5 seems to have cured it.

 

[Boog]

Hinglby, my 2014 R3T had a stutter, different from yours that I think. I induced my problem by over filling the gas tank. I know this does not fit your situation, but on very hot days, with an overfilled tank, my bike would give me fits. Since then, I only filled it the bar and not the top of the neck, and I have not had the problem.

For your matter, and reading all that you have done, I think the fuel pump may be the issue whether it is an "O" ring or just the pump is going out. It doesn't sound like you let the bike sit for long periods of time so I wouldn't necessarily think it is getting 'gunked-up' with ethanol issues or other 'old' gas problems.

 

[pjsmithres]

Boog
I have also had the over fill problem twice. Must be the vent and vacuum at the top gets stupid.
Now I only fill to the neck guard or less.

 

[hinglby]

This is great information! Thanks!

I have a new fuel pump, pressure regulator and filter in my shop. I'm thinking about pulling the tank and swapping these parts, but I'm curious how an over filled tank would cause a problem? Can I open the tank and blow through the vent lines?

The temp here in Arizona fluctuates. Last Saturday when I left the house it was 85F, 90 minutes later I was in 60F and filled the bike. Two hours later I was in 105F and filled the bike. The problem was there all the time.

I've reflashed the computer with different tunes. I had my friend (owned a shop) reflash the stock tune, no help.

I'll try some of the suggestions above over the next day or two and will post any results. Keep the ideas coming though. I still love my Rocket, even with this problem it's still the best bike for me.

Thanks again everyone!

 

[hinglby]

Well I did the fuel pump test and it revealed nothing as described by Pjsmithres. It did reveal another problem though.






I'm not sure this is a cause of the hesitation or studder, but it surely isn't helping anything. I will figure out how to get the rust out and replace the bad parts.

I'll post more later today.

 

[Willtill]

Uftttt.... that doesn't look good. One of the reasons why I always keep a full tank of fuel in my bikes. That helps negate any room for condensation in the tank.

 

[hinglby]

I ride every day and fill the tank whenever the idiot light comes on. The bike has never been in storage and has never gone more than 2 days without being ridden.

I think the biggest problem and cause is the new fuels. The fuel tank frame that holds the fuel pump, regulator and filter has a thick white corrosion with some rust spots. If I remember correctly, steel and iron rust... Aluminum corrodes with a white residue. The only piece not corroded is the pressure regulator. As far as I can tell the pressure regulator is the only aluminum part in the tank.

I'm leaning toward some bad fuel. This amount of rust can't be just condensation.

Now, how to clean and get it up to speed.