05 VFR, increseased vibration/VTEC Clatter

My bike has just under 12K on it. All I have done to it since I bought it with 6.6K miles on it is change the oil, tires and do the basic flapper valve and pulled the snorkle for a little more intake noice. I have recent;y been commuting 80 miles a day on the freeway and as of a bout a week ago, I spilled a good amount of gas from the tank down the left side. I have noticed since then that my bike has developed a very coarse vibration when running. My chain is set to about 1 1/4 inch sag and I thought it may be bad gas, as I filled up at a United OPil station that was much chea[er than everyone else. I have since run the tank down to about 1 gallon left and refilled with Shell gas, which my bike seems to prefer and I added an ethonal fuel treatment.


The vibration really seems to resonate throughout the frame. I reved it up and you could actually hear the resonation move through the frame.It sounds like there is something loose, CCT or something. I am going to ride it for a while tomorrow and see if running different gas helps. My chain is lubed up and not kinked anywhere. I do rev it up and bounce it off of the rev limiter, but most of the time I am around 5.5 to 6.25K rpom on the freeway and 4-5 around town.



Ideas? I did notice the other day that the VTEC rattle at light throttle sounded different. AGain, it sounded loose. I also changed the oil today with newCastrol Power Racing RS 10w40 which is what I have run since I bought it. My last oil change interval was approx 4.5 to 5K miles while on a Wix filter. This oil change I have switched to a Mobil1 M110 filter because it is a little higher volume. My oil level has always been where it needs to be, at least on the upper edge of the two lines on the oil sight window, taken with th bike on the center stand.



Could bad gas cause an increase in vibration? Really, it is the same as it always has been, just more coarse. Fuel mileage and power is the same. I'll update tomorrow after I have ridden it a bit more.



Ideas? I really need this bike to be ok, it is my commuter.

 

Bad gas could be one of the reasons. I know you lubed and adjusted the chain, but does it have 'flat' spots?

 

How old are the tires?

 

I didn't notice anything unusual in the chain, it is a pretty uniform. The tires were new in August 12 and have about 5-6K on them. I am goiong to lift the tank and see if perhaps a vacuum hose came loose, look for anything obvious. I'll post back after.

 

Check the intake boots on the throttle bodies as well. if they aren't seated one cylinder might be firing off and could cause a bit more vibration.

 

I ended up running three tanks of good gas with 5 ounces of Seafoam per tank. It was running pretty rough while it was on the first and second tank, surging throttle and kind of jerking on the initial throttle. By the third tank it started smoothing out quite a bit. Now, I am on the second or third tank without it and it's running a lot better. Just before I used the Seafoam I changed the air filter, not the combo has got it running very well and my fuel mileage has come up about 3-4 mpg.