High Altitude Switch???

[Warthog]

I have heard about the high altitude switch on the older K bikes on this forum and have just now got around to getting serious about finding out more.

I was at my BMW dealer this weekend and asked about and they said that they knew about it and that there was a chip of some kind that plugged into a socket and they had only sold a couple over the years.

I got home and dug into the Clymer manual and found a short paragraph about it and managed to locate the plug on the left hand side. The manual mentions a loop plug. It also said that this for use when riding abouve 4000' . I'm in Colorado Springs and we are a little over 6000' so I figure I should consider setting the bike up for high altitude.

Questions:

1) Is it worth the effort?
2) Do I really need to purchase another part from the dealer.
3) is there a way to wire a switch so I can switch back and forth between modes?

[Burnszilla]

There is no chip in the part. It is just a loop that plugs into that socket. If you are at over 4000 ft than I would get it. I plugged the loop in and cut the wires and ran them to a switch. Whenever I'm riding in the Sierras and my GPS says greater than 4000 feet elevation I flick on the switch. At higher altitudes your bike will run rich since there is less oxygen. IIRC, the loop tricks the EFI and allows more air in. Without the loop/switch the K75 chokes riding over the passes.

part#
1131459504 contact ring $8.00

[soldemall]

It is nothing but a little jumper harness. Just went out to look again at mine to be sure. Check www.maxbmwmotorcycles.com website. Their parts catalog is online. See the chassis harness, item #8;
part #61131459504 contact ring.

[Warthog]

Stephen I remember you mentioning the high altitude switch before and that is the way I need to have mine set up. Am surprised the dealer had not sold more of them.

Thanks for the help

[PHMarvin]

Re: High Altitude Plug

What they said! The only reason I don't have the altitude plug wired to a on/off switch on Harriet's K75 is all the switch locations in the dash plate are being used! So I have to remember to remove the plug if I ride much under 4000ft - not too likely around El Paso!

[Burnszilla]

I thought it would be cool to find an alititude switch that senses the elevation automatically closes when above 4000 feet.

[Eric1514]

The "switch" might also be overkill. I live at 4500ft and my k75 runs fine. When I go to Flagstaff, 7000ft, the bike idles a little slower at stop lights but runs fine at speed. YMMV.

The switch causes a lean condition and I'm afraid that if you run it on when you don't need it, you might cause engine damage. Installing a real switch like Burnzilla did with, perhaps, an indicator light would be the way to go.

Eric

[Warthog]

I saw a dash pad on Ebay that had an extra switch and I was out bid by a buck a the last second. I also need a replacement ABS switch because my light in mine is burnt out. I have not been ale to find the bulb nor the dealer so it looks like I have to do the entire switch. Will probably order two switches and anABS switch for the pad. Want to add a witch for driving lights.

Colorado Springs is 6035 and most of my riding is local between here and Denver and the mountains so I think I'll give the switch a try.

[breyfogle]

The "switch" might also be overkill. I live at 4500ft and my k75 runs fine. When I go to Flagstaff, 7000ft, the bike idles a little slower at stop lights but runs fine at speed. YMMV.
Eric

I have to second Eric's opinion. When my K75 was new, I bought the high altitude plug and carried it everywhere until I finally realized that I could not tell the difference when the plug was in or out. If it has any effect at all, it is subtle, definitely not a "must have" mod.

[PHMarvin]

Hi, Eric, Breyfogle, et al,
I'm glad to see that your bikes don't stumble and give you problems at altitude when not using the high altitude plug. I keep the plug in Harriet's bike most all the time (El Paso is near 4k ft. and traveling in any direction, you are at that altitude or higher for quite some time) and it, too, runs fine. Maybe the plug isn't a necessity, but I feel better using it. The good thing is, though, we're discussing it. That way, newer owners discover the plug exists and is still available from BMW. After all, the newest bike which uses it is almost 12 years old and even if the bike does get dealer service, the dealer may not remember the plug exists or may not remember to discuss it with the newer owner. And for any who don't know, the plug is for all 2-valve K-bikes (K75 and K100) used at altitudes of 4000ft and above.

[Warthog]

Thanks for the discusion. I guess for $8.00 I can give it a try and see how it affects my perfomance. I am especially interested when I head to the mountains which rapidly goes from 6 K to 8-9K.

[RICHO2006]

Will engine damage occur if the bike is operated under 4000 ft. with the plug installed?

[PHMarvin]

Will engine damage occur if the bike is operated under 4000 ft. with the plug installed?

Hi, Rich,
We once rode to Tucson (the late Rob Lentini's Memorial) and forgot to switch the plug off once we were lower than 4000 ft. Tucson is about 2400 ft. altitude. We discovered the error while in Tucson and took the plug out of the system. There were seemingly no ill effects. I don't know what would happen if the bike were run for an extended time with the plug in the system at, say, sea level.
Ride Safe,

[breyfogle]

Will engine damage occur if the bike is operated under 4000 ft. with the plug installed?

IMO, ... no

[Burnszilla]

Will engine damage occur if the bike is operated under 4000 ft. with the plug installed?
I accidentally left my switch on for a week. I always wondered if that is was caused my #1 exhaust valve to burn out. It was either that or an air leak in the throttle body tube. Both can cause a lean mixture.

[wmubrown]

I figure I should consider setting the bike up for high altitude.

Questions:

1) Is it worth the effort?
2) Do I really need to purchase another part from the dealer.
3) is there a way to wire a switch so I can switch back and forth between modes?

The "device" is a loop of wire that plugs into the socket you found, nothing more. 1) YES it is worth the effort, especially where you live! 2) It would be a cleaner install to buy the part from the dealer, it's cheap as I recall 3) yes you can wire a switch!

As others have pointed out, you do not want to accidentally leave this thing in the lean (switch closed, in the ON) position. You cut the loop on the plug you will buy from the dealer, and solder the ends to the switch. Get a toggle switch that locks into the OFF position. Check out www.mouser.com p/n 611-7101-031 You have to pull the lever out before you can flip it up in the ON position. I did this on my last K100RT bike and ended up never using it (it's flat here in MI and I did not get back out to CO on it as expected).

John A. Brown
Kalamazoo MI 49009
'95 K1100LT

[Warthog]

The part came in on Friday. :newtoy The guys at Colo. Springs BMW are quick..

Unfortunately, a little thing called snow put my road trials on hold thru the weekend. Forcast for tomorrow looks promising so I have my fingers crossed.

Of course it I was Burnszilla that would not stop me.....

[cjack]

The "device" is a loop of wire that plugs into the socket you found, nothing more. 1) YES it is worth the effort, especially where you live! 2) It would be a cleaner install to buy the part from the dealer, it's cheap as I recall 3) yes you can wire a switch!

As others have pointed out, you do not want to accidentally leave this thing in the lean (switch closed, in the ON) position. You cut the loop on the plug you will buy from the dealer, and solder the ends to the switch. Get a toggle switch that locks into the OFF position. Check out www.mouser.com p/n 611-7101-031 You have to pull the lever out before you can flip it up in the ON position. I did this on my last K100RT bike and ended up never using it (it's flat here in MI and I did not get back out to CO on it as expected).

John A. Brown
Kalamazoo MI 49009
'95 K1100LT

I wondered about leaving the switch on. I used to have it wired to a BMW switch on the dashboard. I heard once that it leans 10%. I don't know from what, but my K100 engine always seemed reasonably rich and I figured that 10% lean would not kill it at sea level...probably. It worked well to turn on the switch in the mountains, otherwise the bikes ('86 K100RSes) would backfire frequently. I never was able to detect any performance difference with the switch on or off.

[SIBUD]

I thought it would be cool to find an alititude switch that senses the elevation automatically closes when above 4000 feet.

There is, at least some form of it. I tried to buy a jumper for my K1100LT and the dealer said the bike already knows and adjusts on its own.

[cjack]

There is, at least some form of it. I tried to buy a jumper for my K1100LT and the dealer said the bike already knows and adjusts on its own.

The Motronic has a sense of air pressure and adjusts accordingly. Different from the LE Jetronic in the K100s.

[Warthog]

Well the weather cleared - sunny and around 60 degrees. Took the K bike out for a spin and while not an expert I noticed improvement in the low end acceleration. The bike always seemed a little slugggish starting from a complete stop.

Does running an overly rich mixture cause the engine to be sluggish?

[wmubrown]

Well the weather cleared - sunny and around 60 degrees. Took the K bike out for a spin and while not an expert I noticed improvement in the low end acceleration. The bike always seemed a little slugggish starting from a complete stop.

Does running an overly rich mixture cause the engine to be sluggish?

Yes. Ever leave the choke on when an engine is warmed up? It lacks power, smokes bad, smells worse because it's running too rich. Lean it out and it runs smoother, faster, cleaner, and obviously uses less fuel.

[Warthog]

Was working on my bike this weekend and had the lower fairing off and decided to check the plugs. Pulled them and they all looked pretty carbon fouled which according to the Clymer book indicates a rich mixture. I suspect this is the result of running the bike at 6K feet without the high altitude plug installed.

[wmubrown]

Was working on my bike this weekend and had the lower fairing off and decided to check the plugs. Pulled them and they all looked pretty carbon fouled which according to the Clymer book indicates a rich mixture. I suspect this is the result of running the bike at 6K feet without the high altitude plug installed.
That would do it...

[mcassoccpa]

I accidentally left my switch on for a week. I always wondered if that is was caused my #1 exhaust valve to burn out. It was either that or an air leak in the throttle body tube. Both can cause a lean mixture.


I was blissfully ignorant of this high altitude loop until today, when I saw one for sale on eBay. "Hey, my bike has one of those..." I bought mine in Albuquerque last year, and have been running with it installed in Dallas [elev. 470 ft.] ever since. I had noticed the wire loop, but it looked like someone had defeated a sidestand switch, to me. Needless to say, I'll be checking my sparkplugs. And removing the loop.
FWIW, the bike has been running just fine, and that includes two-up rides to Austin and Eureka Springs, AR., and the solo ride home from Alb. I haven't noticed any difference in engine performance wherever I've been, so hopefully this is a non-issue. [Fingers crossed...] It does backfire from time to time when decelerating, but from what I've read that is a common k75 complaint...

[mcassoccpa]

Well, I'm sure everyone's been on the edge of their seats :rolleyes , so I'll end the suspense. The plugs looked just fine. I removed the plug, and the bike started as usual, and performed as usual. Actually it seemed to have a little more snap, but I'm going to attribute that perception to the new seat I installed, and also rode for the first time. The bike fits me so much better now that it feel like the bike behaves better. I guess I broke the "assess one change at a time" rule...:laugh

[HFbmw]

I always look forward to riding above 4000 feet! Soon as I plug that thing in the mileage jumps from 40 to over 50mpg! Leans out the injectors. Blasting thru the curves on I-70 west of Denver and doing it without stopping for fuel as much!

tim lindstrom
91 k100lt