Top end surging:

Yesterday I was being bad and trying to top my bike out, however, once I approached 125mph I noticed the bike starting to surge, naturally I backed off. This wasn't vtec kicking in as I was at 10k rpm. It was pulsing and definitely making more power during the surges, it wasn't clutch slipping as the rpm was stably climbing. I have suspected my bike was a little under powered compared to what it should be but had no way to be sure so there might be something a little wrong on the inside of the bike.

What do you think could cause this? I was thinking spark plugs as they might be original to the bike but only have 3.5k miles on them now.

 

I'd give air filter and plugs a look-see first if it was mine and the same thing was happening. Possible a quality fuel system cleaner treatment also, I believe in Chevron Techron and feel that most of those cleaners are "Snake-Oil". I've seen a few engines before and after being treated with Techron and the stuff did make a difference. I bought my '07 last year with 3350mi and when I gave it a look through I found a rodent nest on top of the air filter. Mine ran fine but that's an example of what you don't see can still hurt.

 

Another thing I noticed is the bike will not hold a steady RPM at a constant throttle position, will move around by as much as 1k rpms. No idea what can cause though unfortunately.

I will say this bike is a joy to work on, everything seems easy to get to, however, I still can't figure out how to get the fairings... Gave up once I realized I didn't need to.

 

Sounds like you're running out of fuel. Getting in to a lean condition will cause surging. I would start with that assumption and start looking in to the fuel system and or mapping.

 

Think I might have found the problem. One plug looks really bad so I assume I was running 1 cylinder down a good chunk of the time, also explains my shitty mileage. When I put the new plugs in and started the bike it blew white smoke for a good 10 minutes, I assume that was from burning off all the carbon buildup in the misfiring cylinder. No idea why the FI light never came on and threw a misfire code though...



New CR9EHIX-9 plugs replaced all 4 and I may or may not have done a vtec wheelie which the bike could not do before. Bike feels way more lively.

 

Okay just to prepare me for the worst how long should a front head gasket replacement take? 10 hours?

 

Who is doing it? Are you able to do it yourself? Is there a mech. in the picture?
A mechanic will have a book that tells them time to do projects. IMO a untrained person could do the jobs faster then they say.

 

I am going to do it myself. Never done a head gasket before but having done everything else on my bikes before I see no reason to not do this myself. Service manual does not say how many hours to do it as far as I can tell.

 

It seems extreme to assume the head gasket to me considering how much of it's life the bike has sat, unridden, poor lil thing. Are you going to run with the new plugs for a while and re-inspect before doing the big job?

Here's a link to "reading" a spark plug. Seems to me the plug wasn't burning at full pop and simply fouled. The build-up looks consistent with any fuel fouling or build up from E-10 fuels.

NGK Spark Plugs USA

 

At this point I am more inclined to think it is a stuck piston ring. But yes I am going to run the plug a while and see what happens.

 

Check the ignition coil for that plug. A friend's ZX6R did the same thing when one of the coils died.

 

Before you tear anything apart do a compression test. Warm motor, throttles wide open.