Air injection system?

[guitardad]

I've started poking around at Hans, my R65, and it's becoming apparent it's a California bike.  Apparently it was originally fitted with an air injection system, even though it's a '79 and my Clymer says these systems were fitted to California models from 1980 on.  There is an additional air inlet port, near the exhaust pipe.  The system was intended to allow a little air into the exhaust gases, to let any unburned hydorcarbons finish burning.  You can see the air inlet here....



Thing is, the manual shows plumbing that connects the air inlets back to the airbox.  My airbox has noplace for a fitting to connect.  So what's the story here?  Should there be an air injection system, and I just can't find where to connect it?  Did BMW get ahead of the curve, and have a head design ready for '80 in '79?  Or do I have later model heads on this bike?  Any ideas?

[Justin B.]

These were standard on all (or at least most) Airheads starting in 1980 till end of production.  It's possible that your heads have been replaced with a later set of heads.  You can easily and neatly plug these ports with oilhead oil drain plugs.

[Bob_Roller]

What are the last 7 characters of the frame and engine VIN ? If it's original both numbers should be the same, the frame number is on the steering head area, and the engine number is over the engine oil dipstick hole. It's also on a label below the right cylinder, but from your picture, it probably isn't very legible. That will tell you for sure what you've got. Post them here, and we can tell you the month and year of manufacture.

[guitardad]

VIN Stamped into the frame is 6381394.  Numbers on the engine, above the dipstick, are the same.

I had an '88 R100GS for a while, and it had the airbox cover with the two "snorkels", an the flat air filter.  I could see on that one where the hoses should go into the airbox.  But this bike has the older aluminum airbox cover, for the tube-shaped filter.  I just can't see where there are any holes in the airbox cover for the other end of the air lines.

[Bob_Roller]

Your bike was manufactured in 03/79, so I don't think you have the original heads installed on your R65. Replacing the remnants of the air injection with a plug looks like your best solution. How did you come to get a west coast bike, out there on the east coast of the US ?

[nhmaf]

At least 50% of the airhead riders I've known have replaced/removed these air injection systems, so you're
ahead of the curve - I wouldn't try to retrofit one on your bike as the metal airbox wasn't intended to have the
plumbing for this system.   These air injection systems work OK when they work, but when they have problems they
can create a variety of annoying symptoms.    I'd just follow as Justin suggests at some point and get some clean
bolts in there to plug up the holes, though maybe you don't want to try to remove the old plug bolts if they've become too
corroded.   Put some Permatex Anti-seize on the new bolt threads first if you do replace them.

Your bike isn't in that terrible a shape, at least the pushrod tube seals and base gasket on the left side look fine in the picture.

Don't despair, we can help if you get stuck !

[guitardad]

Your bike was manufactured in 03/79, so I don't think you have the original heads installed on your R65. Replacing the remnants of the air injection with a plug looks like your best solution. How did you come to get a west coast bike, out there on the east coast of the US ?

The PO bought it sight unseen on ebay, back when his son lived in Oakland.  He kept it there for a couple of years, to ride when he flew out to visit.  Eventually he decided it needed more than 100 miles a year and shipped it back to Maryland.

I keep thinking there has to be a more elegant solution to plugging the ports than the squeezed-off tubes that are there right now.  But the head is threaded for a nut, not a plug, right?

[Bob_Roller]

The part that is threaded into the head is called a 'union' it is threaded on both sides, so if you can get the nut with the remains of the tubing off of the 'union' all you need is a nut or cap. To remove the 'union' may prove to be difficult after 28 years !

[Justin B.]

I have removed this crap from 4 bikes and have never had any problems with the "union", in fact I would say that 2-3 of them were actually loose!  I think what you need is two of the drain plugs and two associated crush washers, here are the BMW part numbers (somebody correct me if I'm wrong):

07119919117      PLUG, M16X1
07119963252      SEAL

I wouldn't worry about any anti-sieze as you don't want them to come out anyway!  I would install them, tighten the hell out of 'em, and then re-torque after 500 miles or so...

[Semper Gumby]

+1 what Justin said....

[tagordon]

I just found on my 91 R100. That the thread size for the union is not the same as the drain plugs. I ordered the drain plugs & washers for the heads. Also the rubber plugs for the airbox. Installing revealed that the drain plugs are a different size.
Will measure & post when size known.
Troy

[Justin B.]

Interesting.  I have used the Oilhead drain plugs on 1980, 1981, 1984, and 1995 Airheads.  [smiley=huh.gif]

[tagordon]

Opps!
I ordered the wrong drain plugs.

Justin,
Thanks for the reminder - OilHead not AirHead plugs.
There is a 2mm diff in thread size.
I was not paying attention. I know I have read this info several times.
And still, I ordered the wrong part. Glad they are cheap.

Troy

[Justin B.]

That'll do it every time!  They look like they practically belong there...

[guitardad]

OK, a follow-up here.  I got the unions out of the cylinder heads - after two weeks of dousing them with PB Blaster once a day, they came out easily.  Here's what I found:



And another shot from the ends:



Yep, that's right.  One is solid, so there's no way air was getting in anyway!  The left is solid, the right is hollow, so just the crimped-off air tube was blocking off outside air getting in.  When I pulled the spark plugs, the left was nice and tan, the right was a lot blacker.  Coincidence?