Can a 6th gen burn a valve?

[FearIsGood]

Couldn't find an answer to this question with the search function, hopefully it wasn't right under my nose. There's a friend of the family that I talk to every once in a while and every time I see him he says I'm losing power and that I'm going to burn a valve. Today he decided I was probably losing 35hp (exact number) by not mapping the bike. I do respect his opinion because he has a lot of drag car experience and I've only been riding since May. However, I'm quite sure he hasn't tuned any bikes with oxygen sensors and quite possibly none that are FI. I've had a few friends ride it and we all seem to agree it isn't slower than it was (if we take off down the road I'm not getting left behind). Also, I've put 2k plus miles on it since the new exhaust and it runs the same as it did then. I'm no expert so I bring it to you guys.



Anyway . . . thoughts?

[nvoges]

This does apply to a carburated bike, but the FI system should account for any loss in backpressure. I wouldn't be concerned if I were you.

[pjvtec]

I'm sure you're not losing any power. I've have Dyno training, and Honda ProTech Certified. I would love to custom map my '04 VFR, but I chose to leave it stock. If Honda's FI map was burning valves, they would do something about. Please, this is just plain silly. Throw your bike on a dynomometer with an exhaust sniffer that tests for air/fuel ratio. If your bike is too lean, something is wrong.

[Action]

First, 35hp is silly. Thats like giving up a third of your total horsepower. Second, that cat thats sitting up stream of you pipe is giving you plenty of back pressure. Thats why putting a slip on exhaust on an otherwise stock bike gives little to no performance improvement. I would just tune this guy out all together.

Action

[FearIsGood]

Oh, forgot to mention...when I took the exhaust off I hogged out the cat. I'd say it's approx 70% unplugged.

[John451]

Have you tried anything to tidy up the Undertail ?

Have seen Gen 6 VFR with a similar USeat exhaust removal although rather than an aftermarket end can he had only a straight through trumpet with staintune spud welded in the end sounded good if a little loud but when following the huge underseat gap looked very very odd....

[FearIsGood]

I still can't figure out what to do there . . . defninitely not going back to undertail because I must have dropped 20+ lbs.

[Lgn001]

Burned valves caused by a lean fuel condition are kind of a thing of the past. It can still happen, I'm sure, but it must be very rare and would most likely occur in air cooled motors.

The biggest contributor to burning a valve is inadequate seat-time, as in the valve not being in contact with the cylinder head long enough to dissipate heat. If your valve clearances are where they need to be, it is generally not an issue.

Valve materials, and metallurgy in general, have come a long way. Older exhaust valves, when they overheated, used to stretch. When they would stretch, the valve clearance would tighten up, and the valve would lose seat time, which would make it hotter, and it would stretch more, etc. etc.

We have probably all known somebody with a 60's VW that burned up cylinder #3. It was common practice to adjust the valve clearances on that cylinder .002 looser than the other three cylinders to prevent the afore mentioned failure.

So in short, it is probably not an issue. You could pull a spark plug or two to see what they look like. That will give you an indication of any mixture problems.