Damn air tubes!!!!!!!!!!!

[12960]

The one thing I always hated about the airheads was those lousy plastic air tubes going from the air cleaner housing to the carbs.

They never fit right and are a pain to get on and off.

I just finished going over an R75/7 engine and ordered new rubber manifolds for the carbs.

They are the exact length of the original ones.
I put them on, no problem.
Then I went to put on the plastic air tubes and they are way off.

If I force them on they push back the air cleaner housing about 1/2 inch.

What gives????

How do you get them to fit correctly.
I've been riding airheads for 20 years and am not new at this but I'm baffled.

Gerry

 

[sgborgstrom]

I think there's a "left" and a "right" air tube. Any chance you got one on the wrong side?

 

[12960]

air tubes,

No, It's hard to make that mistake but I did go back to the garage after some choice cursing and shaved some thickness off of the rubber manifolds and the plastic at the air cleaner housing and they fit pretty good.
I think the manifolds were a tad too long and perhaps the air cleaner housing was too far to the left.

I'm getting old and cranky.
Especially since all my wannabe biker buddies bought expensive Harleys and keep bugging me to do the same.

They keep asking me how I can stand the embarrassment of riding with them to
the Harley events , me being the only BMW there.

Well I reming them that when I say I was to Nova Scotia and Glacier National Park and other far away places, that I RODE there. Trailering doesn't count when you say I WENT somewhere on my bike.

Gerry



Gerry

 

[20774]

As mentioned, there is a left and right. Also, the one on each side can be turns 180 degrees...it makes a difference. The trick is to have everything loose and work all the pieces together to finally get them to fall into place.

 

[barryg]

Assuming they are lined up properly to start with this is a suggestion for the next time they are removed. Use a sharpie or magic marker and label them left and right . T hen mark them to the proper alignment to to the airbox on one end and carb sleeve and carb on the other end. This helps on reasembly. May not help this time, but maybe the next. Barry

 

[NEALART]

Sorry, there is no supplier for new, better tubes.

However, if you join airheads.org and attend a few tech sessions, you will have new better friends who tell stories about riding to Alaska.

As far as getting old and cranky, I feel your pain brother.

 

[AnnapolisAirhead]

Just an alternative idea, you could put K&N cone pods on each carb and do away with the rear tubes and airbox in general.

I put the tubes on the airbox, clamp them. Then tilt the carb such that the forward outter lip is tucked inside the cylinderhead tube and the rear, inner lip of the carb is tucked inside the airbox tube. Then, with a little wiggling, it walks right into the tubes. Hold the carb firmly with one hand and tighten the clamps completely.

Hope it helps.

 

[lkchris]

Been too long since I traded my '78 for an '84, but I can report for the '84:

The tubes are now same right and left.

The rubber sleeve at the filter end of the tube is simply pushed down onto the tube before placing the tube in position. When it's in position, simply slide the tube back up and onto the filter housing. Piece of cake.

 

[rocketman]

Just an alternative idea, you could put K&N cone pods on each carb and do away with the rear tubes and airbox in general.

I put the tubes on the airbox, clamp them. Then tilt the carb such that the forward outter lip is tucked inside the cylinderhead tube and the rear, inner lip of the carb is tucked inside the airbox tube. Then, with a little wiggling, it walks right into the tubes. Hold the carb firmly with one hand and tighten the clamps completely.

Hope it helps.

if you do that then you have to re-jet the carbs since the air flow intake is higher, or at least I did on my /5 when I went that route cause it was running lean, even at 3/4 to full open where the main jet is the main fuel regulator. I've also heard that the tubes work better because the volume of air in the tube acts like a sort or "ram air" effect. How true that is, well....? sounds good though!

The K&N's tend to fall off til you get it all clamped and sized right and in really hard rain if they they get really wet, performance suffers ( don't ask me how I know these things! Ha Ha!)

RM

 

[20774]

The tubes are now same right and left.

The fiche lists two different part numbers for left and right for an '84 R100RT. Because of the offset rods on the crank, the carbs are also offset with respect to each other. How does BMW make them the same part if they have to cover different distances to the air cleaner? Are the outlet holes from the air cleaner also offset the same distance?

 

[bikerfish1100]

i've found it much easier (possible vs impossible) if you loosen the carb to rubber hose clamp at the intake spigot.

 

[AnnapolisAirhead]

if you do that then you have to re-jet the carbs since the air flow intake is higher, or at least I did on my /5 when I went that route cause it was running lean, even at 3/4 to full open where the main jet is the main fuel regulator. I've also heard that the tubes work better because the volume of air in the tube acts like a sort or "ram air" effect. How true that is, well....? sounds good though!

The K&N's tend to fall off til you get it all clamped and sized right and in really hard rain if they they get really wet, performance suffers ( don't ask me how I know these things! Ha Ha!)

RM

Undoubtedly, it would change the mixture. It was just an extreme thought. Better yet, learn to wrestle the bastards back on and live with it. A small sacrifice for an amazing machine.

 

[lkchris]

The fiche lists two different part numbers for left and right for an '84 R100RT. Because of the offset rods on the crank, the carbs are also offset with respect to each other. How does BMW make them the same part if they have to cover different distances to the air cleaner? Are the outlet holes from the air cleaner also offset the same distance?

ETK shows one part number, 13 72 1 262 787 quantity 2.

Indeed the outlet holes in the air cleaner are offset to compensate. Not so good looking on the old style but not even noticeable on the new style.

 

[MOONDOG59]

If I remember right I had a devil of a time with my 1983 R100RT. And I don't remember exactly what I did but I think I changed the position of the rubber adapter at the airbox end. Once I got it to fit I thought about how the mech-n' nech at the BMw place had installed it wrong. The adapter was reversed or fit better on the outside or something. It has been awhile. I just remember how better it fit and what a "genius" I was......