Hello
I recently bought a 72 R50/5 (first BMW)
It had sat for a little while so I disassembled and cleaned the carbs (deluxe rebuild kit)
I have a question (issue) with what is the correct float height?
The Bing book and Clymer say to adjust the height so float arm is parallel to carburetor base (~0.4" from base). This is significantly different then how the old floats I took out were set. They were set so the floats were at about a 15 degree upwards angle (as seen on bike). My issue is that if they are set parallel to the base then the Ticklers (fuel enrichener) do not reach the top of the float So they can not be used to add additional fuel for cold starting (ie no "choke')
This seem to me like there might be something is wrong (eg tickler to short?) or I am misinformed
FYI, I also installed new coils, plugs, wires, points and condenser and have had it running (a little rough) with both old float height and 'correct' height I say running a little roughly as in I have not had much experience balancing the carburetors and that may take a little practice to get correct I have not checked the value clearance and know I need to. It is the next thing I am going to do
But back to the float height, any advice? or any thought?
thank you for your time
cheers malcolm
If you hold the carburetor upside down with the float resting on the needle and seat, the feature line should be parallel to the bottom of the carb body, which would now be facing up. This is your baseline setting. Those Bing slide carbs can be difficult or impossible to restore when let to sit with old fuel for a very long time.
former Airmarshal, IL.
hello,
I think I found the issue (someone pointed me in the correct direction)
In the No 1/1984 Bing tech-bulletin there is an explanation of how with the newer floats "the tickler becomes ineffective as a starting aid"
This matches what what I observed and so I will be resetting the float height, checking the value clarence and then work on synchronizing the carburetors
Any thoughts on the "no choke"
I could maybe have longer tichler rods fabricated or try a pair of Mikuni carburetors (granted $500 just to have carburetors with working chokes is a bit)
thank you
-m
The 1 owner I know personally who went to Mikunis is very pleased with them. However there are negatives associated with the install. The kit has 2 identical carburetors, so the adjusting screws will be inboard on one side.
That bike, (an R60/6) had been left parked and un-ridden for decades. The half a tank of gasoline had ruined everything in the fuel system.
former Airmarshal, IL.
I found the issue (someone pointed me in the correct direction). In the No 1/1984 Bing tech-bulletin there is an explanation of how with the newer floats "the tickler becomes ineffective as a starting aid". This matches what what I observed and so I will be resetting the float height, checking the value clearance and then work on synchronizing the carburetors.
Any thoughts on the "no choke"? I could maybe have longer tickler rods fabricated, or try a pair of Mikuni carburetors (granted $500 just to have carburetors with working chokes is a bit).
OK, so you like to use the "ticklers" to start the bike, I get that. But if you raise the float level to make that possible, then you've also made the bike run "richer" across the entire RPM spectrum. The float brings the liquid level up to a position that works with the jets. If the liquid level goes higher then it's going to be like you took a drill to all the jets. Your plugs will be black and may foul out.
It will be so rich it will certainly crank easier, but you'll be fixing the 1% at the beginning of the ride and ruining the 99% to follow. In my book that's not a solution.
You really should extend the shaft of the tickle button.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Advertisement
