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K75RT altitude plug

tullypilot

New member
I bought an altitude plug (contact ring) for my trip through the mountains but it came with no instructions. Where does it plug in?
 
On my '87 K75S, it was under the rear of the seat on the left side.
But it really didn't seem to make much difference, it still idled poorly on Mt. Evans...
 
Probably too lean at 14,200 feet; but it ran quite well lower down. Many of the bikes (and cars) up there wouldn't run at all, especially the carb'd ones, so they'd coast down for a bit & then start! :D
 
Probably too lean at 14,200 feet; but it ran quite well lower down. :D

Just the opposite. The higher the altitude, the thinner the air (less O2). Less O2 for a given amount of fuel = too rich. Exactly what the altitude plug is meant to help with. If your bike is running on the rich side to start with, then even with the altitude plug at altitude it will still be too rich.


Easy test:

1. Get your bike fully warmed up at the altitude where you live(ride it around for 15 minutes).

2. Let it idle, note idle speed.

3. While it is still idleing, push the starter button. Note idle speed.

4. While it is stil idleing, install altitude plug. Note idle speed.

If your mixture is correct, both #3 and #4 should cause the idle to drop and about the same amount (around 50 rpm). If starter button drops less or actually increases idle, you are running too lean. If altitude plug drops less or increases, you are running too rich.



:dance:dance:dance
 
'Twas a long long time ago with several bikes in between... :gerg
All good info nonetheless.
I've been looking on the A&S and MAX parts fiches - what page is it on? Ya got me curious now.
 
'Twas a long long time ago with several bikes in between... :gerg
All good info nonetheless.
I've been looking on the A&S and MAX parts fiches - what page is it on? Ya got me curious now.

61_2725 Chassis Wiring Harness

See link in post #3 above for link to picture of where it plugs in.



:dance:dance:dance
 
Altitude plug location

On my '92 and '95 K75's the plug is on the left side zip tied to the frame behind the side cover at the rear portion of the fuel tank. An exact type plug (low altitude plug) already plugged in.

Charlie
 
You have other problems if it idled poorly. Chances are your base mixture is wrong or the valve adjustment is wrong.

Back in the day high altitude problems with K-bikes were the result of vapor lock due to the superheated fuel.

In any event, don't think there's any such thing as a "low altitude plug." It's either no plug for low altitudes or the special plug for high altitudes and if something's in there it's a high altitude plug.
 
There is a dust cap (shown in the previously reffered to pictures) that comes inserted in the socket when the altitude plug is not being used.


:dance:dance:dance
 
Many of us also did the spliceroo and installed a rocker switch in the dashboard where the key is. Then we could just toggle it into the circuit or not, depending on altitude. It did make a difference on my '85 K100RS.
 
Many of us also did the spliceroo and installed a rocker switch in the dashboard where the key is. Then we could just toggle it into the circuit or not, depending on altitude. It did make a difference on my '85 K100RS.

They ONLY way to go if you live in California and ride the Sierra passes alot!



:dance:dance:dance
 
Yes, and with a little artistic creativity one could convert a switch with triangle logo to look like picture of a mountain!
 
BMW used to offer a switch with a mountain emblem on it. NLA. I just used a pilot label maker and put ALT on the switch.



:dance:dance:dance
 
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