I had a previous thread https://www.wristtwisters.com/#/topics/80019. I replaced the tank, fpr, pump, all fuel lines, and spark plugs. My idle is set between 11-1200. The only other thing I did was add a Speaker led headlight. So.....I got it all back together, filled the tank with ethanol free and seafoam, and went for a ride.

When I first give it throttle in first gear, it has like a “chatter” and the exhaust sounds really throaty before it goes into the power band, otherwise it ran fine. I jumped on the interstate and it was running ok, no one around, so I opened it up a little. At around 90, I shifted into 6th, got to 100 and then no matter how much throttle I gave it, there was no added power. It sloowwllly climbed to about 110. It didn’t bog at all like before, but I don’t really know where to go from here.

Is your tank venting correctly? Next time you go for a ride and it starts bogging, pull over and carefully open the tank cap. It should open quietly. No suction or movement of air.

I went through things today, there is no vacuum issues with the tank. It rides fine, it just won’t go over 110 even with the throttle buried. It’s like I’m getting no power in 6th. It shifts in solid. I did replace the tie rod between the shifter and pedal but the spline is at 11 oclock and it shifts through all the gears

Perhaps dirty injector/s from all that rusty crap. There is a basket mesh filter/screen in each injector.

My ZX10R did that. I replaced the fuel pump after thinking about if for quite sometime. Cured.
Just a thought.
Good luck.

I changed the FPR a few months prior to replacing the tank and pump. Should I change it again? Is there anything to clog in the FPR, or should I just clean the injectors

You can't clean an FPR. If it's new it should be good.
You did remove to black rubber transit bung from the main port before bolting it down?
Before pulling the injectors check the plugs. They may show which injector is playing up.
Inspect your injectors for obvious blockages.
The best way to clean injectors is by taking them to professionals. They'll test em too.
Before going to the effort of removing your injectors eliminate everything simple first.
Check your plugs, coils, wiring etc. Recheck the fuel delivery system, all your recent work etc.
Feel the headers when the bike first fires up, to be sure all cylinders are heating equally.

I know I can’t clean the fpr, but could I have ruined it using it with the crap tank?

My bad, I misread your post. I got it in my head you had asked about cleaning the FPR.
I wouldn't have thought you could have ruined it. As long as fuel is running through it it should work. Can you see if the fuel return hose is doing what it should?
Just to eliminate you could replace it.
Is your fuel pump a new OEM?

Brand new oem pump assembly and return hose. I took the fpr off today just to make sure I hadn’t been drinking when I installed it and all looks good. The exhaust smells like unburnt fuel. It was acting worse than ever yesterday, super jerky and sputtering in first at take off, almost didn’t make it home. My battery light flashed once and my Speaker headlight was strobing everytime I took my hand off the throttle, so I started thinking it was battery related...like maybe the pump wasn’t getting enough juice, battery tested 13.11

Fuel does shoot out the return side of the fpr with the bike running. I don’t know what it means, but cylinders three and four get alot hotter, faster than 1 and 2, but they eventually even out.

With fuel in the return line I'd say your FPR is fine.
OEM fuel pump should be fine.
All four headers should heat up equally. So somethings not right there.
You should check your plugs. Is there a difference between all four?
I don't think it's coil related since one coil runs plugs one and four and the other coil two and three. Yet you say headers one and two are slow to heat. Does this mean they aren't getting enough full? Perhaps.
Injectors one and two are at the "dirty end" of the common fuel rail. When your bike is on its side stand leaning over the fuel rail is tilted down, any crap in your line will settle down that end, at one and two. I'm thinking injectors one and two are dirty.
Check out the last couple of posts in this thread... First two cylinders not firing Help https://www.wristtwisters.com/forums...ad.php?t=29366
Just make sure your plug leads are fine too.
My bike sat for years before I got my hands on it. It had a rusty tank, filters full of a fine red crap, like mud. Bike still ran OK? But after I stripped it down I found the mesh strainer basket on injector full of the same red crap.

So, I finally got sick of messing with it, called the local Honda dealer and they told me to bring it in. Managed to make it there ( bike actually was great up until the last 3 miles) and when I got there, they said they didn’t have the expertise to diagnose it (and tried to sell me a 500). Called the only other Honda service center around and they won’t touch it either. They said (without looking at it) it’s probably a piston. It’s going to get the injectors cleaned at a mom and pop place and if that doesn’t work, here comes an MT09 or Speec Triple

I tested the battery at 13.11 and running at 14.4. The spark plugs look lean, but it’s running at low end like it’s flooding. My guess is a stuck injector. Today, all cylinders heated equally except 3 heated up twice as fast

Maybe 3 heats up fast cause it's running lean. Lean for hot, rich for cool. Perhaps the no.3 injector is partially blocked causing a lean condition.

Update: Local shop had it for 3 months, said they couldn't figure it out. Got it back, searched forum, on a whim I pulled out the thermostat.......intermittent stuck open....never even thought of that

That's interesting, I'm running without ANY thermostat at all in mine and she has tons of power. Even if you're in very hot or cold areas, this shouldn't cause the problem you describe. The system will simply alter the fuel ratio and she'd run as if cold for longer. Mine was in the middle just as if I had the thermostat in there once it got hot.

I'm looking at over 100 F today and have ridden in over 105 F.

I removed mine because she wasn't opening and was overheating.

I'd be very surprised if a stuck open thermostat would cause the bike to not have enough power to go over 100.

Was the slow high RPM power still there? Meaning if you're in 3rd and mid way up the power band, did she pull hard all the way to the red line? I know it's hard to tell because you're talking about 80HP vs 110HP or whatever the ratio is, but seems very odd.

You could test this by removing the thermostat and see how she runs, then compare to it being in there.

A stuck open thermostat can mean that the bike's fuel map stays in quick-warmup/cold engine mode and runs over-rich because the coolant is not reaching normal operating temperature, no matter what the outside air temperature is. Too much fuel can cause loss of power and breaking up, especially in higher RPM ranges.

That was what I was thinking, but now I that I ready KarlJay's post, I don't know what to think. I'm in Florida, it's hot. I left for work after getting the bike back from the shop, rode great and full power. Bike sat for 8 hours while I was at work, and went to start it up to go home and it didn't want to start. It idled at around 900 instead of the 1200 from earlier in the day. I just let it sit and idle and noticed that the temp needle barely budged. Normally when it's just idling it will go up about half way and drop once out and running. Anyway, on the ride home it was blubbering during low idle and I really had to give it throttle where it would finally break through the blub, blub, blub at about 3500rpm. It would accelerate but very slowly. I smelled like I dumped gas all over me by the time I got home. I pulled the thermostat and it was stuck open about a 1/4", wouldn't budge in or out of a pot of boiling water. My above post about finding the problem was a little premature. Using your logic above, I was sure I had found the problem, but won't have the new thermostat until tomorrow.


List of things done so far:
New Tank OEM
New Fuel Pump OEM
New fuel lines OEM
New FPR OEM X 2
New Yuasa Battery
New plugs, changed 2x now


Shop:

swapped tank/ plug wires from another bike to see if that made a difference
said they did the injectors and they were fine, not entirely convinced though

Like you said your thermostat has crapped out. Once that is sorted the bike may be fine.
If not perhaps consider swapping out the temp sensor.
Are your coils good?

Couple things missing from the list that can affect fueling: The engine temperature sensor and the air temperature sensor. The former is the most critical as it is what determines base fueling for the bike and their typical industry lifespan is about 10-15 years. I don't see any mention of you testing or replacing these.

I bet lunch money that you could remove the thermostat and the bike would run the same. I've been running without one and we're expected to hit 104F today. I've been running several days like this and at least one was over 100F.

If I didn't remove the thermostat myself, I wouldn't know it's not in there working perfectly.

I'm not saying it won't matter, but I really can't see it causing the problem that you describe. Maybe if you were in a very cold area it would be different.

One thing that was interesting, and you should look closer, is that it worked great then it didn't. The other is the smell of gas. I have that now too after I removed the tank. She was actually leaking all over from that rear tube on the left under the tank. The one that's low pressure, seems it didn't seal properly and I "fixed" it, but I still smell the gas.

One other thing, you can have more than one problem. The stuck open tstat was one, the gas smell another... that doesn't mean they are related to the power loss issue.

Finally, did you check for proper ground? When I hear of these issues, I think something electrical. Given that you replaced most everything concerning fuel (except you didn't list fuel filter), I'd start looking at the ground connections (including that one under the tank, I broke that one removing the tank). The power to the computer, etc...

I had a battery cable that looked perfect but was rotted inside. You couldn't SEE it, and it still worked sometimes, but you could FEEL it, it was rotted inside and it was so bad you could feel it. That can happen to any wire.

I'm not sure how to test how much amperage a wire can pass, I think there's a safe way, I just don't know what it is.

Well, that didn't work. I went through the wiring, cleaned ground under the tank, cleaned contacts. My jw speaker headlight has been flickering, put a multimeter on it and am getting 11.9 volts at the light. I'll post a video of what the bike is doing, it's also making a clicking sound from the case while idling, no idea.

https://youtu.be/j1nFIkvpQzE

Failed voltage regulator?

Shop said it tested fine, said charging system was good, I'll have to check it myself. I'm still leaning toward an injector problem, 1&2 heat up way slower than 3,4. Three heats up faster than all of them...this with a laser thermometer on the pipes.

Yeah I've never heard of a 919 regulator failing.
If your problem is injector related how does that explain the flickering headlight? not enough rpm?
The way the injector rail is setup cylinders 1 and 2 are at the far end. This end angles down when bike is on sidestand. Crap in the fuel system can settle at this end. Did on my bike which had sat for years. I found rusty crap in the filter baskets on injectors no1 and 2. I replaced these two injectors.

Yeah not enough rpm I guess on the headlight, when I rev it, light comes on solid

1. you have 11.9 at the headlight, that's not enough. What do you have at the battery? You should be 12.6~12.8 or whatever it is.

2. IIRC, you replaced a whole bunch of things (tank, pump...). Did you remove the injector rails and clean out the injectors?
Some injectors have small filters at the top that can clog up.

If you don't want to remove the injectors and clean/check them, you can also remove the plugs after doing what you just did in the video (hold it stead at 3000 RPM, or wherever it sputters), then kill the engine, remove the plugs and compare. This isn't easy, but it's an old trick. You create the problem, kill the engine and read the plugs to get clues. Hard to read them because it's a very short run, but it can be done.

Personally, I'd tear down the injectors and clean them. You can have them rebuilt or get a $20 high pressure fuel pump and see if they are spraying correctly. You can also use a battery and a can of carb cleaner. See YouTube for home made fuel injector cleaners.

One other thing to look at might be timing. I don't know how it can be off, but IF timing can ever get off, It can sound like that. Long shot because I don't think the timing can even be adjusted, but IDK.

On another long shot, disconnect the headlight and shut off any other electric drain and see if the voltage has changed at the battery and if that changes how it runs.

Some systems just can't work properly if the voltage is down by very much. 11.9 might seem fine, but the system might not function properly below 12.6.

You can put a fully charged car battery on there with jumpers and see if that changes anything. Even a strong battery charger can pump the voltage up while it's running and see if that changes how it runs.

Some things (injectors, pumps, etc...) really need all the voltage of a fully charged system, so if you have a small problem with charging, that could be the problem. Pretty easy to check with a strong car battery and/or charger.

Do NOT use a battery charger or a car's electrical system while it is running to help power a bike's electrical system. Your voltage regulator will freak out and probably fry. A battery is fine, a strong (50A+) charger is NOT.


Also, how old is the battery? Have you had it load tested? A battery can show as fine on a voltmeter but have problems (or even be shorted internally) that result in problems like this.

Battery is a brand new Yuasa, bought on Amazon last week. Runs no different with the headlight disconnected. I tested again with the probes directly to the lead and got 14 volts. Anyway. Tried to warm it up today, only had a few minutes to mess with it, cylinder 3 heats up stupid fast, like 400 degrees on the pipe when all others are at 250. I pulled the plugs and did a compression test ( not very accurately because the bike only warmed up for like a couple minutes, then took me another 30 mins of it cooling down to get everything ready. Compression was consistent across all at 115-120. I know it's supposed to be 180 but assume not warming it up fully could affect that. Pics of the plugs: these were brand new a week ago.

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Is one of those plugs wet? Bit hard to tell.
Just maybe no.3 header gets hotter cause it's injector is partially blocked causing a lean issue or its getting extra air from somewhere. Vacuum hose leak?

Those plugs do look wrong. One is wet and two are leaner. Is the wet one also the cold exhaust?

If you have a multi meter, you can check the plug wires. IDK how to test the coils off hand, but I'd look at them.

I'd probably start by cleaning the plugs and running the engine for a few min then pulling them. Paying close attention to the wet one. I looks like the fuel isn't getting burnt. So if they coil isn't firing all the time or at full power, that could be the problem.

Maybe a local shop has a spare set of coils they can put on and see if that changes anything. I used that trick on someone's bike that wouldn't start.

It's the 1 injector that looks wet. Probably won't get much done until next week with this hurricane coming.

So if the plug from cylinder 1 is wet...maybe no spark. Do you have spark at no.1?
Could your starter valves, on throttle bodies, be way out of sync?
FWIW you can listen/hear the injectors with a long handle screwdriver.

Good questions, i'm figuring out how to test this stuff as I go. I'm pretty confident at this point that my injectors were never touched by the shop. I'll check the spark again. Shop told me they swapped wires with no change.

"shop told me they swapped wires"
There might be something to this.
So they swapped out the ignition wires? with what?
If your plug is wet that kinda tells me the cylinder is getting fuel. Next I would make sure that cylinder had spark. If no spark go over the shops work. Most likely a bad connection.
Putting this out there for everyone.
What's a safe way to test for ignition spark at the plug for these bikes?
I know what I'd do if it was my lawnmower or chainsaw.

I've been around for a good while, I've learned not to trust shops. Harbor Freight sells a cheap spark tester, but I'd be concerned that it might be an intermittent type problem. Borrowing a known good set of coils/wires makes the test pretty easy.

The HF tester is just a wire gaped inside of a plastic case. Not hard to make one, you run a wire to ground, wire to end of plug, then have a gap between them where you can see the spark. You can also ground a spark plug to the engine and see what color the spark is (best done at night).

Remember, the engine block is a grounding point, IDK where the engine ground is, but it needs one somewhere.