engine quit just after starting

[RayMCannon]

Has anyone had problems with the new ethanol type gasoline.. They put 10% in in De. and I suspect it is the problem since my bike sat for 4 weeks. It is a 1988 K75S

[cjack]

Has anyone had problems with the new ethanol type gasoline.. They put 10% in in De. and I suspect it is the problem since my bike sat for 4 weeks.

We ran two K100RSes on it for 10 years or so with no issues.

[PGlaves]

Since this is in the K bike forum I assume we are talking "K" bike. But I don't know which "K" bike.

Classic K bikes, including the K75, K100, and K1100 are prone to damage from the use of gasahol. The damage occurs in the form of softening and dissolving the rubber mount that holds the fuel pump in place in the tank. This is not a hugely expensive part until the black goo gets sucked into the fuel pickup, accomplishing some or all of:

- clogging the injectors
- clogging the fuel pressure regulator
- clogging the fuel pump

When all of these things happen at once you will spend more for replacement parts and labor to fix the bike than some of the asking prices for classic K bikes in recent marketplace ads.

You can avoid the big problem by biting the bullet and periodically checking and replacing (if needed) the rubber mount for the fuel pump. About a $60 part if I recall correctly.

Once a year might be often enough to remove the pump and check the mount. When it feels spongy or gooey get it out of there. If you use gasahol all or most of the time, or store the bike with gasahol over the winter, then checking before you do anything else in the spring is essential.

The state of Kansas adopted a law last year or the year before, that eliminated the requirement that ethanol adulterated fuel be labeled at the pump. At the time I sent photos of a new pump mount and a blob of goo pump mount, as well as the prices for the mount, pump, regulator, and injectors to the Governor and the legislative leadership. I never got a response, but didn't really expect to get one. They are far more interested in the donations and junkets from the corn lobby than the problems of a mere motorcyclist, I'm sure.

And - so as not to spare anybody - BMW has been aware of this problem since at least 1990 and has had ample opportunity to alter the spec for the rubber used in this part. As far as I can tell they haven't done that yet, and probably never will.

They seem to have avoided the problem on the Oilhead and later bikes, so maybe only those of us who are dinosaurs will continue to suffer the problem. I'm sure BMW figures I just ought to buy another new bike.

As an aside, there are other items which will be affected by gasahol. Both the fuel pump and the injectors are lubricated by the fuel. The ethanol in the fuel causes it to be less effective as a lubricant. So, the injector pintels and the fuel pump are more prone to mechanical wear. Most folks get rid of their bikes before this is likely to be an issue, but high mileage bikes will have worn more due to the adulterated fuel. Injector wear is a key cause of old K bikes running richer than when new. Bigger hole - more squirt - richer!

Avoiding fuel "adulterated with alcohol" was a recommendation contained in the first Haynes K75/K100 manual I bought back in 1986. Still true today!!

[cruise_carter]

Good info Paul.

When the fuel pump mount dissolves, does fuel leak out or is it just a mount internal to the tank?
When I was looking at the Max BMW parts fiche, are you talking about the vibration damper attached to the pump?
Dale

[98lee]

Paul was talking about the vibration damper. And yes, it is inside the tank around the fuel pump. Would not cause leak. Just gums up the internals of the injection system.


:dance :dance :dance

[mrich12000]

Here in Ontario,Canada we have 10% in regular 87,89 But not in the higher grades which I use, and as recomended I use sh#ll (91)
But I do monitor for my little water problem and the internal tank pump mounts..

[deilenberger]

Has anyone had problems with the new ethanol type gasoline.. They put 10% in in De. and I suspect it is the problem since my bike sat for 4 weeks.I might suggest you check the "Z" crankcase hose - it's behind the rearmost throttle-body. When these crack they allow unmetered air into the intake, and stalling at idle when cold is a symptom.

Just a FWIW - it may be a coincidence.. it's been known to happen.