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raYzerman wrote: ↑Thu Dec 02, 2021 9:52 pm I don't think there's much indication of a fuel pump/pressure regulator issue at this point. Symptoms would be different and more widespread, like losing power at higher rpms and accelerating.

Clearly this is not a linear problem. Not an inability to provide sufficient fuel at peak demand but somewhere something is not providing correct fuel or ignition or air under what should be an easy state to maintain.

The problem has been ongoing for over a year unsolved? Its time to bring a shotgun to the party. Buying and installing a new fuel pump would be costly but swapping a gas tank only requires friendship, trust, beer+pizza, and perhaps 30 minutes. I'd swap gas tanks with someone long before I'd let you borrow my TPS, APS, or ECU.

Plus, if the problem moves to the other FJR you really know you have found it.

And problems tend to hide where everyone knows simply can not be the source of the problem.

In my career I have come across situations where oscillations appeared where one would think should have been the easiest conditions to regulate. Stable and steady is pretty hard because only small corrections are desired. Acceleration and deceleration are easy because you accept whatever rate of change you get.

I'd sure like to get my hands on this bike after the first of the year.

I'd also like to ride VA after the first of the year.

Hmmmmmm

Sooooo, my 06 was driving me KrZy8-Banannas. Long of short? Intermittently failing fuel pp. Not a full failure, but partial... just enough to reduce minimum fuel pressure/volume.... and just once in awhile. Took forever to find that easy fix (swap 2013 tank onto 2006)

Good luck..

Just catching up on this conversation, thank you all for your input! Festus rebuilt Jolene and then I bought her, rode her for almost 2 years before this surging issue showed up. Since the surging began, it's been over a year and we have thrown so many parts at her:

- TB sync (twice)
- Fuel injector cleaner (twice), the kind you add to the gas tank
- Seafoam in the gas tank
- Oil change
- Air filter change
- Coolant change
- Fresh fuel from numerous gas stations
- Vacuum lines all removed, cleaned and inspected
- Throttle body removed and cleaned, then re-synced
- Throttle Position Sensor replaced (original was in spec anyways)
- Acceleration Position Sensor replaced (original was in spec anyways)
- Spark plugs changed less than 3,000 miles ago
- New OEM battery
- Never seen an error code
- The bike is totally stock

At this point I'm done throwing money away, especially on those expensive sensors. Yet the surging remains, always around 3K RPMs and until I power out of it. Hold the throttle in that position, or slightly higher RPMs, and she bucks like a bronco.

Swap tank (and fuel pump) with someone to see if that is the issue.
Swap out entire fuel rail (including injectors) with someone - injector cleaner may not be enough.

An afternoon with someone with a suitable donor bike could eliminate fuel delivery as an issue...

I too suggested the trivially easy gas tank swap.

Even easier, test the 3000 RPM surge with the gas cap open. Best attempted with half tank of gas or less.

Maybe your bike hates carrying you around.

I have a spare tank. I'll have to check and see if the fuel pump is on it. If not, we'll swap mine out over the holiday.

Good point on the gas cap open, the vent system can get crudded up a bit, but I still don't really think that's the issue..... unless the pressure regulator (integral to the pump) isn't working properly....
The interesting part is it is at a certain rpm..... and seemingly nowhere else.

Festus wrote: ↑Thu Dec 23, 2021 12:05 pm Maybe your bike hates carrying you around.

I have a spare tank. I'll have to check and see if the fuel pump is on it. If not, we'll swap mine out over the holiday.

Well, at least his bike looks good on a calendar.

wheatonFJR wrote: ↑Thu Dec 23, 2021 5:43 pm Well, at least his bike looks good on a calendar.

Thanks! I actually took the picture LOL

Well, those who said fuel pump might have nailed it.

Went by Viper Dad’s this afternoon, swapped tanks and the problem went away!

Pulled his fuel pump and cleaned the filter best we could. Put it back in, he took it for a test ride. He said it was better. So fixed with swapping tanks, better with cleaner filter.

I think he’s got the new pump inners coming.

Hopefully we can put this to rest.

I hope you were taking notes from Wheaton Jr.'s episode..... same basic pump....
How bad was the filter?

PITA (you have to make a test hose), but you could check pump output, spec. 43.5-56.6 psi, although there is no flow spec I'm aware of. Fuel pressure regulator valve is part of the entire pump assembly, FYI. Higher pressure would be a good thing.

You might want to have a look at the inlet filter baskets on your fuel injectors. If the filter was that dirty, there is a good chance injectors are as well. Not that expensive to refurb.

It looked like a used tea bag. Not really any crud stuck to it that you could rub off. Probably a new filter would work but we couldn’t see how it comes off and didn’t want to break anything poking around.

It's basically a screen to weed out the big pieces... pump might be OK. Typically just a friction fit onto the pump, might have a clip to keep it from coming off. Can clean with vinegar, it will clean up iron oxide.
Worth checking the screens in the injectors as Ross mentioned. If your second tank/pump 'fixed it' then that may not be the issue, but I'd clean/replace screens anyway.
Screen and O-ring kit for Yamaha outboard F150..... https://www.ebay.com/itm/203132174846?h ... SwN2Rffl7k

raYzerman wrote: ↑Fri Apr 08, 2022 10:15 pm Screen and O-ring kit for Yamaha outboard F150..... https://www.ebay.com/itm/203132174846?h ... SwN2Rffl7k

Are these the ones that fit the FJR injectors? Yamaha says to replace the o-rings if you take them out...

Yes, as reported by a forum member somewhere in the past..... contains complete o-ring kit. I've had injectors out before, if you're careful you won't lose one or damage it... wee smear of silicone grease, should be good.

Festus wrote: ↑Fri Apr 08, 2022 8:40 pm Well, those who said fuel pump might have nailed it.

Went by Viper Dad’s this afternoon, swapped tanks and the problem went away!

Pulled his fuel pump and cleaned the filter best we could. Put it back in, he took it for a test ride. He said it was better. So fixed with swapping tanks, better with cleaner filter.

I think he’s got the new pump inners coming.

Hopefully we can put this to rest.

Thanks for the update Festus. So good to hear. I'm sure ViperDad was so frustrated with the surging all this time. I'm happy to hear you guys finally got to the bottom of it. Congrats!

See what happens when you celebrate too early? Viper Dad and his son installed his fuel pump replacement motor today. Still surges.

He said he noticed that when they opened the tank, twice (don’t ask), it seemed to release an excessive amount of pressure. That has me questioning if it’s a vent issue.

Not that many moving parts in a tank so it’s odd that switching tanks worked but changing fuel pumps didn’t. Only thing left is the vent, right?

Go for a ride with the gas cap unlatched and less than a half full tank. Problem will go away if it is a venting issue. I think this was suggested earlier.