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[SIZE=14pt]All righty then![/SIZE]
[SIZE=10pt]Warsw has posted how gas is distributed in a NEW THREAD! [/SIZE]

Thank YOU Warsw for creating a new thread to discuss gas distribution based upon your experience in the industry. Others, please feel free to post there after you read; I'm actually looking forward to this. So, give some credit where it's due, Warsw has stepped up and delivered details which can be debated/refuted/approved.

and NOW, back to my sick little FJR! :rolleyes: :glare:

 
Jebus, Carver... just shoot the mutha and put it outta it's misery, make an insurance claim of a drive by (those gangs in Creston are vicious) and buy another Harley. Problem solved. ;)

:bleh:

 
Jebus, Carver... just shoot the mutha and put it outta it's misery, make an insurance claim of a drive by (those gangs in Creston are vicious) and buy another Harley. Problem solved. ;) :bleh:
City slicker.. they ain't called gangs.. theyze called 'Millitias' as in the Creston Militia. :comando: :trinibob: :comando: ...and, have you seen those new Harley UltraClassics? :rolleyes:

 
Latest update.

Head pulled, problem found.

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flecks, e.g. small particles of carbon under 3 & 4 valve seats preventing sealing. Tech says it would have gone away on it's own and must have just happened. So, on with a light seat dressing, clean up, and reassembly. At least this makes me feel somewhat better in that I didn't notice a lack of power because it most likely was running just fine until right before taking it in for service.

I'm not a tech but I remember dear old dad pouring water down the carb to make steam in the cylinders for the purpose of cleansing.. Makes me wonder if it would work here too. Or maybe just a 10k rpm tune up?

Also makes me wonder what caused the carbon build up; I run regular gas as recommended, only name brand service stations unless in Death Valley where I ran whatever I could find. Shit, I'm old, knit sweaters while wearing granny glasses and all, but the bike does see regular upper rpm use. Never lug, the minimum rpm while in motion is above 3k so I'm saying I don't dog the engine nor red line it either.

Thoughts anyone?

 
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I've read about this in the past, seems that plenty of WOT is whats called for.

 
Doesn't have to be "carbon buildup", at least not in the way it's phrased. Deposits are part of combustion, period. Ever notice piston crowns, once run, are always black? Carbon. Very tough stuff, carbon down the road a bit does become diamond after all. A little bit caught in a valve seat can dump cylinder pressure very nicely. Usually, though, the carbon that causes this problem comes from the exhaust valve, more specifically, the exhaust port, valve guide, or the backside of the exhaust valve. Some dislodges, hold the exhaust open just a tad, and whammo, burnt valve. One never sees the intake valve with this kind of problem, if the intake has debris keeping it from sealing, it's dirt from a improperly sealed, or none at all, air filter. At least I can't say I've seen it. It's possible some flaked off of the piston crown, and in the very short period of time the intake valve is open as the piston begins to travel up on the compression stroke it found it's way there. For two cylinders to do this though, borders on the most improbable. Was intakes, right? Sure it was carbon, or was it crud? In any case, it helps the case for using a fuel additive occasionally (Chevron Fuel System Cleaner, Sea Foam, etc), or even a tankful now and then of premium fuel, which tends to have a bigger detergent load than regular (here it comes). And yes, water injection does clean chamber deposits nicely, but can also cause the very problem we speak of-carbon once dislodged can find it's way into a valve seat, and no more compression. Also, once something has lodged in the seat-valve face area, it is usually there for good, and/or a burnt valve quickly follows, there's no "blowing it out", as combustion heat will weld the particle to the surface it has landed on. Prevention is the best policy, but even with that, sometimes luck just plays a part-good or bad.

 
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WOT plus buy some mid grade for your baby every once in a while you cheap bastard!!

 
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DC,

I think Crazy8 thinks it's a Harley - after all, it's parked next to one, right?

Glad it wasn't more serious - I was getting nervous. For that matter, so was Wonky.

I'm gonna go out front and buzz the neighborhood at 9K for a bit ........ it's work, but somebody's gotta do it.

 
edited to remove potential political content

 
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Frequent bursts of throttle, however, are best for keeping the chambers clean ......and most fun. Flog it, it needs it.
I am going to print jestal's response out for the next LEO I meet, will store it right under the seat. Jestal, can I have your full set of credentials so that when I go to court... :biggrinsmiley:

 
Glad it isn't more serious and especially that you're going to be back in the saddle soon. :yahoo:

Jestal -- always an enjoyable read and an education. Thank you, sir. :clapping:

 
WOT and high RPM will usually keep the chambers pretty clean and the rings moving. High RPM alone doesn't do it so riding around in first gear at 9000 at part throttle or revving the engine in neutral is pretty pointless. The motor needs the chamber pressue, heat and extreme turbulence of WOT operation to really clean things up.
One thing common in high performance, compact combustion chambers (like the FJR) is dedicated squish areas..i.e...where the combustion chamber matches the piston shape and the piston comes very close to the cylinder head. So.....the take-away here is that high performance engines with a lot of squish do not like to be babied. They need to be exercised regularily at high RPM and WOT to keep carbon buildup at bay.

Some high RPM probably would, though. Frequent bursts of throttle, however, are best for keeping the chambers clean ......and most fun. Flog it, it needs it. One purposeful maneuver that is relatively safe and benign is to leave the trans in 2nd gear, hold full throttle as the engine runs up to high RPM then let off and let the engine decel or engine brake back to a reasonable RPM then whack it open again and run it...then engine brake down. Do this a dozen times or so. Cleans the chambers, moves the rings around on the piston (high RPM and light throttle will cause the rings to flutter and rotate on the pistons) to keep the ring grooves free and is an excellent way to load and unload the engine to effect breakin when new.
I hear that Yamaha is looking for a new technical writer, especially this kind of advice for it's customers. :yahoo:

Very informative post Jestal, that I quickly translated into a good run up and down one of the High Sierra passes close to my home. :D Carbon build up, what carbon build up? ;)

Them damn CBA guys, sheesh. :p

 
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Frequent bursts of throttle, however, are best for keeping the chambers clean ......and most fun. Flog it, it needs it.
I am going to print jestal's response out for the next LEO I meet, will store it right under the seat. Jestal, can I have your full set of credentials so that when I go to court... :biggrinsmiley:
Reminds me of an old Bill Cosby comedy routine. :D

 
Rad- Thanks for your comments. I see you edited yours which is a shame since you had some excellent thoughts. Now I wish my memory was better. :unsure: I wanted to wait to respond until I had a high speed connection, remember you had asked something and now I can't recall. Hey Rad, anyway to convince you to repost? :rolleyes: I won't re-post what I think I remembered you said in case you don't want it here, it's a respect thing.

Jestal -

"Do you remember running the motor relatively easily for a long period and then giving it some high RPM WOT just prior to the issue surfacing?"

The day before the service, I had ramped up to a buckthirty on my favorite 'racetrack'. It was not held there for any great length of time; just enough to touch the stars, see the twinkle, then decrease back to the bounds of earth. The bike was ridden for perhaps an hour after that, at normal speeds of 60-85 then taken in for service. Never noticed any 'performance' problems which is why I was shocked that 3 & 4 were found with low compression. I did notice a decrease in gas mileage about 5k ago, from low 40's to low/mid 30's but blamed our lousy Ca fuel.

"Regarding material/carbon getting from the piston/chamber back under the intake valve seat. Entirely possible. Things go back and forth thru the valves like you would absolutely not believe. There are very strong positive and negative pressure pulses that resonate thru the exhaust and intake system that can easily carry foreign material back into the intake tract so it could be caught under the intake seat.

This makes me feel better. I have to admit my warnometer was going off wondering if this wasn't simply a fleecing of the Yamaha warranty. I'm suspicious by nature, not a good trait, and the fact I didn't personally see the leak down test performed, or visually get to inspect the valves, even though I had asked to see all parts, gave me that 'I wonder if' feeling. Then again, this shop has never fleeced me on any other service, did a great job diagnosing my yz426 bak crank balancer bearing, the tech is Yammie 5 star rated. Still, being anal and all, I would have loved to seen it with my own eyes. That's the good thing about doing your own work.

"They need to be exercised regularily at high RPM and WOT to keep carbon buildup at bay."

Most all of my time is spent at 4-6k rpm. I never operate at less than 3k with load on the engine, and found that mpg went up a few if I kept the engine at no less than 4k loaded. I attribute this to more efficient combustion due to higher intake velocity and better flow. But, honestly, very rarerly does the bike see redline. Guess that will change now and I'll follow your advice to "Flog it, it needs it. One purposeful maneuver that is relatively safe and benign is to leave the trans in 2nd gear, hold full throttle as the engine runs up to high RPM then let off and let the engine decel or engine brake back to a reasonable RPM then whack it open again and run it...then engine brake down. Do this a dozen times or so. Cleans the chambers, moves the rings around on the piston (high RPM and light throttle will cause the rings to flutter and rotate on the pistons) to keep the ring grooves free and is an excellent way to load and unload the engine to effect breakin when new."



"I would guess that some carbon built up due to moderate operation, a burst of throttle along the way unseated some carbon that got trapped under the iintake in this case."

Geesh. Guess I'll have to loan my bike out to SkooterG for one of them incognacio rides.. :rolleyes: (I like the way I got Ignacio's handle in that word :yahoo: )

So, how often should one do the 2nd gear rev 'er up tuneup? Or run some Techroline thorugh the tank? Will the Techroline affect the fuel pump windings, e.g. start to eat them? If so, then is it simply ok to but some Techroline in, then run the entire tank down to refill with 'regular' fuel? Would it help to run a tank of premium once and again?

 
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Thanks Dcarver, Rad, Jestal for this interesting writeup.

Made me go out and blow some carbon out on the freeway!! I hope it is all gone now and promise I will never lug again.

Carver, may your engine get back into shape soon.....that had to be frustrating.

 
edit due to political content

 
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