poor intermittant performance

A month ago I got some BP 89 octane and the next day the bike ran rough and the FI light flashed. I put cleaner in and some 93 octane and things corrected themselves.
Last week I got more BP 89 octane (the stations are everywhere up here in the yoop) and the bike started running rough, cutting out and hesitating for a second or two as I rode along. It has lasted for several days, 3 bottles of isopropyl water remover, and one visit to the dealer where two mechanics rode it and declared it cured. Indeed it seemed cured ... until I had ridden about 50 miles and then it started cutting out again as though I were letting off on the gas quickly for an instant. I'm stumped.

The 89 or 93 octane gas doe's not perform any differently in the Silverwing than the standard 87 which it's designed to run on. The extra octane is not used, and goes right out the exhaust. I know I'll get some feedback on this, but ask the experts, and I think you'll find that they agree that paying for higher octane on an engine that doe's not require it is simply a waste of money.
The 87 has the same additives and cleaners that the higher ones do, the only difference is in the octane rating. OK let me have it!

I too think (or believe) that paying for higher octane than 87 is really quite foolish. Anecdotal evidence is not empirical data, so save the trouble of stating your observed conclusions.

u p tom,

Not sure, what codes were in the system as a result of the flashing FI light? It may be that you've got some fouled injectors, or slogged up fuel filter.

I too think (or believe) that all octane does for fuels is correct pre ignition or knocking. If the engine you are running is not knocking... higher octane is not needed. If it knocks ... boost the octane.

I am sure we have an oil baron on here that can explain it better than I can...

I found this article ... chemist with a Vett... good discussion...

Hope link helps... (and works) ... Gary

Tom:
Did you purchase the gas that gave you problems from the same station? From what you described and how you fixed the problem, it sort of sounds like they may have some water in their storage tanks.

I am not being critical of anything anyone has said about this subject... only adding a little personal experience to the blend so to speak.

I owned an Exxon station for a dozen years and learned a few things about water in gas. One, there is a 4" stand pipe on the bottom of the tank. That means the tank has to have a major amount of water in it before any water is actually pumped to the customer. Moisture does accumulate and collect on BOTTOM of tank due to condensation and occasionally a leaking tank. Did you know that that is the first means of checking for a tank leak? Water will seep into the tank, gas does not leak out (in most cases). I stuck my tank every day putting a moisture indicator on the end of the stick. When the indicator showed 2", I would pump the water out. A trace would be left because of the inability of the pump to actually get it all. I would always request my load of fuel be delivered to me late in the day to allow the tank to settle overnight after the fuel was dumped into my tanks. Second, each pump had a filter on it that would shut the pump down if there was ANY moisture making contact with it. A VERY MINUTE amount of moisture would shut that filter down. Third, if you did get water from the pump, you will not get more than a block or two before something is noticed. And there is usually a line of multiple vehicles with the problem. I am not saying that it is impossible that you can get water in your gas, but not likely if you are going to a branded station that is moving a lot of product.

Are there any experts on here that know of a way to drain the gas tank and lines on a swing? I wouldn't even know where to start, but, if the problem persists, draining the fuel line and checking for contamination would be my suggestion.

Sorry to be so wordy here.

Gary

No worries Opalsboy. I used to live in Michigan (near where Tom is) a long time ago and on several occasions I did get "bad gas" (water in the gas) from a service station there. Maybe things are better with the modern fueling systems, but it is pretty easy to get water in a tank due to the ridiculously high water table (less than one foot in many places). In fact many if not most tanks in Michigan need to be held don using straps so they don't float out of the ground when they get empty. Also, I don't know for sure, but there used to be a lot of "mom and pop" stores in that area that sold gas and maybe they have all had to change out their tank systems, but maybe not. Tom's problems may not be related to the fuel storage tanks at all. The humidity is high enough in Michigan that it is pretty common to get condensation in your gas tank in cooler weather, especially if your tank is pretty empty.

You wouldn't by any chance be having this problem while running about...say... 90+mph indicated on the speedo?

The bike does have a high end governer that cuts out fuel at a certain point.
Although I don't have the details on it, I have hit it many times.

Most people who have not modded their bike for speed never know its there..

Dan:
Isn't the power shut off more of a "rev-limiter" as opposed to a speed limiter. I realize at some point (when the motor is completely wound out) these two parameters may merge into one, but I have hit an indicated speed of 113 and my speed was still slowly climbing (a little bit).

The Scootist wrote:

Dan:
Isn't the power shut off more of a "rev-limiter" as opposed to a speed limiter. I realize at some point (when the motor is completely wound out) these two parameters may merge into one, but I have hit an indicated speed of 113 and my speed was still slowly climbing (a little bit).

I believe you may be correct, sir.
An unexplained cutout of any kind is often blamed on fuel.
And FYI, the speedo typically indicates about 10% over actual.
Where the revs fall in relation to actual speed can depend on load, incline, etc., so 90+ was a catch-all understatement.

Dan