Gen 3 surging

[Festus]

I have photos from the scope. I’ll have to get them uploaded. Two valves in every cylinder and only 1 of the 2 in that one cylinder was gunked up.

[FJRoss]

I have photos from the scope. I’ll have to get them uploaded. Two valves in every cylinder and only 1 of the 2 in that one cylinder was gunked up.

Odd - probably not caused by fuel injection if only one of two intake valves.
I would still do the compression/leakdown. Might not tell you why there is a problem but will tell you IF there is one related to valves.
I wonder if a valve clearance adjustment error was made somewhere along the line and that intake wasn't closing???

[Festus]

I checked the valve clearance about 20,000 miles ago. It was good then, but I also wonder if 1 is out. It’s at 70,000 miles or so, I think. Probably never adjusted, only checked.

[raYzerman]

Carbon on an intake valve not unusual as they run colder than exhausts. Does piston have carbon on it? Inspection camera may be magnifying an issue that isn't there. A bad clearance wouldn't likely have caused carbon, riding like grandma does, but odd that one has carbon and the other doesn't. If it's the outside one perhaps it runs colder. A leakdown test will confirm if that valve is sealing, note a certain amount of leakage is allowed.

Coils - FSM page 8-169 describes resistance check of primary and secondary... where the red/black wire connects to each, put your positive meter lead on it. Negative lead on the other terminal, primary resistance should be 1.19-1.61 Ohms. To check secondary put negative lead on the sparkplug connector, secondary resistance should be 8.50-11.50 kOhms. If that is wrong on conventional spark plug adapters, it is most likely a corroded/oxidized connection of the spring/resistor/spark plug fitting... do not know of coil on plug has removable parts... if you look up the spark plug end and see a screwdriver slot, remove it, clean it, reassemble, recheck secondary resistance.

[Festus]

I didn't do any leak down test. I don't have the tools to do that, but we can certainly get them.

In my opinion, riding these bikes back to back, is that this bike is running a little rough. It's very small, but it's noticeable when swapping from bike to bike. Accelerating, you can't tell it, it feels the same, but just tooling along at one speed, there's a little vibration in the seat that I don't feel on my bike and at idle, I swear I can tell a difference. Viper Dad says he doesn't notice it, but he hasn't ridden both bikes.

Here's a few random photos. Sorry for the poor quality. I didn't think they would be relevant so I wasn't paying as much attention to them as I should have, I was just snapping photos because I hadn't poked a camera into an engine before.


Piston top - Piston Top - Side view of open valve
intake valve on far left of bike - same - random cylinder wall and bottom of different valve
A little crud - pretty clean - crud

[FJRoss]

I have seen worse but not sure what to expect on an FJR.
Go at it with a few tanks with Yamaha Ring Free. I think it is more effective than Seafoam.
I would still like to know if anything is leaking past...

[1911]

^^^^^what he said^^^^^^

viewtopic.php?t=5178

[raYzerman]

Referencing 1911's post, I mentioned I'm not sure RingFree is the answer, or any fuel additive.... to remove carbon without disassembling the head, either remove airbox and spray atomized water..... or (in former days... and I can't find anything suitable now), one could spray a combustion cleaner directly into a hose attached to the sync port (I wouldn't necessarily recommend that with water). Seems all the good combustion chamber cleaners were discontinued......
Seafoam is mostly naptha, need something stronger with benzine or harsher chemicals in combination......

As for leakdown, I recently bought a compression tester that had various size spark plug hole adapters and a long nipple that would accept an air hose fitting.... this is what you use to do a leakdown test. Piston at TDC and say 90 psi or so of air, if a leaking valve it will come back out the intake port... normally you would warm up the engine and do the compression test first...

[Festus]

We will work towards that as time permits. He's getting the bike back this week some time and is going to ride it for a little bit to see if the problem is still there. I couldn't replicate it, but maybe he can.

Do you think that the the one valve being cruddy could be a result of a miss? That would back up the bad or weak coil theory?

[Powerman]

You must have infinite patience. I would work on it intensely for a week and then set it on fire.

[FJRoss]

We will work towards that as time permits. He's getting the bike back this week some time and is going to ride it for a little bit to see if the problem is still there. I couldn't replicate it, but maybe he can.

Do you think that the the one valve being cruddy could be a result of a miss? That would back up the bad or weak coil theory?

So, any news? Just when it seems to be narrowed down to one or two possibilities, a bunch of new issues come up. Going around in circles! Carboned valve could be nothing or the smoking gun.

I still think you need to nail down compression/leakdown. After that, I would want to see fuel pressure. Try running with O2 sensor disconnected.
I thought the coil swap didn't help?
Still a possibility of a bad TPS replacement?
Vacuum leak or air leak at the throttle bodies?

[Festus]

He picked it up last night and rode it home. Said it was running and idling smoother than he remembers. No issues on surging but also didn't do a lot of testing in the RPM range. That's my test ride on it and his ride on it without it happening, so that's good, but not conclusive. It could be we just haven't met the conditions for it to happen.

I have his coils in my bike and I think it's fine. I'm going to ride it like that some this weekend and see if I can make it happen on my bike.

We have a short trip coming up soon so at this point, we're going to ride them as is until after that trip. If it requires further investigation, we'll do the leak down test.

One thing I noticed that caught my eye, visually, when I had the throttle bodies off cleaning them and all the little ports, I noticed the adjustment on the Throttle Sensor, the one on the far left end of the throttle bodies, was at the extreme of one side of the slots. It's got the slots for adjustment and these were at the far end. I know when he put that on at Intech day, they went through the diagnostics and it met the specs, but I thought it was unusual to have a sensor be at the extreme of that adjustment. Normally factory stuff is really close to the middle of the slots, so that's something I'd like to mess with in the future as well.

Maybe it's a combination of that being off, 1 injector being heavy, 1 spark plug with a gap larger than spec, and a dirty intake valve, any maybe a weak coil? Who knows at this point. Maybe we fixed it, who knows?

[FJRoss]

Give a Ring Free enema and ride the snot out of it. If problem persists, I would still check compression...

I would check out the throttle sensor too - sounds a bit odd to me. The sort of thing I would question if installing it myself but either the tech knows far more than I do (likely) or didn't want to take the time to investigate as long as it met "spec". Could be hiding an unrelated issue.

[Festus]

Give a Ring Free enema and ride the snot out of it. If problem persists, I would still check compression...

I would check out the throttle sensor too - sounds a bit odd to me. The sort of thing I would question if installing it myself but either the tech knows far more than I do (likely) or didn't want to take the time to investigate as long as it met "spec". Could be hiding an unrelated issue.

He's running some LiquiMoly intake valve cleaner in it this tank and the next and we'll see where that leads. We have photos so we can easily check it again and see if it's any cleaner.

The "tech" that installed it would be Viper Dad, assisted by Blind Squirrel, and maybe Powerman, so there's that

[raYzerman]

Prior to Gen3, TPS angle was adjusted so both ends of the scale were in range..... for this one, the FSM only mentions the lower scale, adjust between 12 and 21. Iff'n it were me, I'd check where the new one was installed, and set it say 12-14 for a new TPS. Later one day when it gets worn, one can re-adjust higher and get out of the worn spot...... never saw one at the extreme of adjustment.... worth checking......

However, as I recall, changing the TPS did nothing for the surging, but I would check where it's at.

[wheatonFJR]

Give a Ring Free enema and ride the snot out of it. If problem persists, I would still check compression...

I would check out the throttle sensor too - sounds a bit odd to me. The sort of thing I would question if installing it myself but either the tech knows far more than I do (likely) or didn't want to take the time to investigate as long as it met "spec". Could be hiding an unrelated issue.

He's running some LiquiMoly intake valve cleaner in it this tank and the next and we'll see where that leads. We have photos so we can easily check it again and see if it's any cleaner.

The "tech" that installed it would be Viper Dad, assisted by Blind Squirrel, and maybe Powerman, so there's that

Did Mike leave any extraneous guns at your place? Were one of his side cases open when he left? Just curious.

[bill lumberg]

Nice.

Give a Ring Free enema and ride the snot out of it. If problem persists, I would still check compression...

I would check out the throttle sensor too - sounds a bit odd to me. The sort of thing I would question if installing it myself but either the tech knows far more than I do (likely) or didn't want to take the time to investigate as long as it met "spec". Could be hiding an unrelated issue.

He's running some LiquiMoly intake valve cleaner in it this tank and the next and we'll see where that leads. We have photos so we can easily check it again and see if it's any cleaner.

The "tech" that installed it would be Viper Dad, assisted by Blind Squirrel, and maybe Powerman, so there's that

Did Mike leave any extraneous guns at your place? Were one of his side cases open when he left? Just curious.

[Festus]

Give a Ring Free enema and ride the snot out of it. If problem persists, I would still check compression...

I would check out the throttle sensor too - sounds a bit odd to me. The sort of thing I would question if installing it myself but either the tech knows far more than I do (likely) or didn't want to take the time to investigate as long as it met "spec". Could be hiding an unrelated issue.

He's running some LiquiMoly intake valve cleaner in it this tank and the next and we'll see where that leads. We have photos so we can easily check it again and see if it's any cleaner.

The "tech" that installed it would be Viper Dad, assisted by Blind Squirrel, and maybe Powerman, so there's that

Did Mike leave any extraneous guns at your place? Were one of his side cases open when he left? Just curious.

Might have dropped a Glock but everyone just stepped over it. After all, it's a Glock, right?

[blind squirrel]

Give a Ring Free enema and ride the snot out of it. If problem persists, I would still check compression...

I would check out the throttle sensor too - sounds a bit odd to me. The sort of thing I would question if installing it myself but either the tech knows far more than I do (likely) or didn't want to take the time to investigate as long as it met "spec". Could be hiding an unrelated issue.

He's running some LiquiMoly intake valve cleaner in it this tank and the next and we'll see where that leads. We have photos so we can easily check it again and see if it's any cleaner.

The "tech" that installed it would be Viper Dad, assisted by Blind Squirrel, and maybe Powerman, so there's that

Did Mike leave any extraneous guns at your place? Were one of his side cases open when he left? Just curious.

No. He only deposits those on the side of the freeway.

[FJRoss]

Update?