New Airhead

kmkahuna · Mar 2, 2011

Vacuum ports on flat head Bing CV Carburetor

Hey, Kurt: Mike V. has the same carb and he pointed out that the vacuum take off is right next to the idle mixture adjustment screw... So I am going to make that homemade manometer:

Although yesterday I took the bike to San Diego BMW to show the parts guys what all the time and effort did over the past 7 months, and one of their mechanics, Phil, just had to get out a screwdriver and a 10mm and tinker... Within a few minutes he determined my left Idle mixture port was clogged, which, after I took it home and opened up....had some gunk that was keeping the needle from seating.
Anyway, my neighbor Marc helped me with the delicate operation of scraping the gunk off without damaging the metal, and last night I started her up again and she really, really purrs now...no hesistation from idle to rolling on the throttle, very responsive.

20774 · Mar 2, 2011

kmkahuna said:
Hey, Kurt: Mike V. has the same carb and he pointed out that the vacuum take off is right next to the idle mixture adjustment screw...

If you would have taken a picture of the bottoms of the carbs, we might have been able to see that!!

bob_m · Mar 2, 2011

http://forums.bmwmoa.org/showthread.php?t=34111&highlight=bing+potato

I couldn't help but think of this old thread. To add just another level of detail you could easily paint the lettering on the carbs.

lmo1131 · Mar 2, 2011

So I am going to make that homemade manometer:

We'll be waiting for the photo-documentary that ensues. :lurk

Although yesterday I took the bike to San Diego BMW to show the parts guys what all the time and effort did over the past 7 months, and one of their mechanics, Phil, just had to get out a screwdriver and a 10mm and tinker...

Funny how bringing around an old motorcycle brings out the best in most real mechanics ... they just can not keep from touching them!

And if you think she's running smoothly now, wait till you get those carbs sync'd!

kmkahuna · Mar 2, 2011

Bob_M said:
http://forums.bmwmoa.org/showthread.php?t=34111&highlight=bing+potato

I couldn't help but think of this old thread. To add just another level of detail you could easily paint the lettering on the carbs.

Thanks Bob, what a perfect thread! Great idea, will have to try it.

kmkahuna · Mar 2, 2011

20774 said:
If you would have taken a picture of the bottoms of the carbs, we might have been able to see that!!

Oh...so it's the PHOTOGRAPHER's fault, eh? ha ha hah.... Dude, 1220 pictures and counting. You'd think somewhere in there there'd be a picture of a mixture screw but NO!

bikerfish1100 · Mar 2, 2011

20774 said:
I've heard that slightly tilted in at the top is the best position. A slight tilt shouldn't affect the float action.

As it has been pointed out to me- the tilt that some add in is to give a straighter line for the throttle cable and avoid an extreme bend right at the ferrule. However, the greater the tilt, the more it messes with an appropriate float level. I give very little tilt, deferring instead to keeping the float level consistent left-to-right inside the float chamber. i thought the pics looked to show the carbs as being tilted a bit much.
However- there does seem to be a bit of "acceptable variability" between techs/wrenches.

kmkahuna · Mar 3, 2011

Final pictorial tour...

Last series in this thread....
It has been a pleasure and a privilege to share this experience with you guys, and will post more pics and more wrenching stuff as this new addition to my man-cave continues to evolve, but I thought after 17,000 plus views, it's time to put her to bed...
Total time of restoration (from first wrench to today)
27 July 2010, to 03 March 2011...7 months, 3 days...what a cool ride!
Thanks again for everyone's help and I plan on taking a little victory lap after I get through the CHP and DMV hoops to thank all the shops here in San Diego who helped me get this project done...

Before:

After...

bikerfish1100 · Mar 3, 2011

Kurt-
Nice job, and thanks for the thread. Inspiring.
2 things you still want to do (and i'm sure there are more)- swap valve covers to the other sides. those tilted fins just look WRONG! and there is (was?) a handlebar pad available that nestles into the area between the rises of the h-bars. Really cleans up the appearance.

johnkuhn · Mar 3, 2011

I think the mufflers may need to be swapped as well. They look upside down. Perhaps that was mentioned in an earlier post. I like them that way too, but they may not clear the side cases.

kmkahuna · Mar 4, 2011

johnkuhn said:
I think the mufflers may need to be swapped as well. They look upside down. Perhaps that was mentioned in an earlier post. I like them that way too, but they may not clear the side cases.

John, you're right, they don't clear the side cases! I was wondering about that...The valve covers will be swapped at 100 miles, when I change the oil, check the torque values and adjust the valves again. After that I'll do the manometer synch and the rest of the tinkering will just find it's own path, I'm sure. I did get my powerlet hookups yesterday and will attach the female to the bike...then I will be able to use the same floater with all three bikes.

photorider · Mar 4, 2011

Outstanding job, man!
Thanks for the great thread.
BTW, how do you like your seat?

mymindsok · Mar 4, 2011

johnkuhn said:
I think the mufflers may need to be swapped as well. They look upside down. Perhaps that was mentioned in an earlier post. I like them that way too, but they may not clear the side cases.

You beat me to the punch!

Please either remove those cans and install them correctly or buy me some new glasses.

Theyre making my eyes hurt!.

boxermaf · Mar 4, 2011

But if you stand on your head the mufflers and valve covers don't look so bad!! ;-)

johnkuhn · Mar 4, 2011

I kinda like them upside down. I ran my airhead the same way for several years. The new Moto Guzzi cafe classic has a very similar look.
Obviously, Kurt and I are at the forefront of motorcycle design.

kmkahuna · Mar 6, 2011

photorider said:
Outstanding job, man!
Thanks for the great thread.
BTW, how do you like your seat?

It's comfy, but to be honest, I think the driver's part is almost worn out; the foam might need to be replaced in the future. That is.....after I change out the damn valve covers and the mufflers!. :nyah

kmkahuna · Feb 28, 2012

kmkahuna said:
The plan is to do two rides this month for our club and pull the tranny then. .

Well, my bike has a rebuilt transmission (630$), rebuilt engine seals and a new resurfaced clutch (655$), and a new electronic ignition (220$) for a grand total of 1505$ this time around... all predicated on eliminating a violent lurch in 2nd gear I've had on this bike since I owned it.
Guess What?
Purrs like a kitten...
Lurches like a :banghead

muther

, even after all that.

Today I want to sell this bike...the bike I have put over 6000$ into, that lurches in 2nd gear for a mysterious unknown reason...

Today has truly shaken my faith in airheads. I own a hexhead, and oilhead, and an airhead..... and this one makes me want to just scream "what simple technology? What the hell? Have you ever tried to put the clamshell on? It's insane the way they designed this!

I'll be all right tomorrow. But damn...what the hell do I have to do to get this bike to accelerate in 2nd gear without lurching like a bucking bronco?

Rear end??

Drive shaft bolts?

What?
Maybe the lightened flywheel is the culprit?

benthic · Feb 28, 2012

Kurt! Say it ain't so! Yours is the first inspirational build thread I read before starting my own. I have every confidence you'll get it figured out!
spencer

radar41 · Feb 28, 2012

What he said!

benthic said:
Kurt! Say it ain't so! Yours is the first inspirational build thread I read before starting my own. I have every confidence you'll get it figured out!
spencer

Kurt,

Don't give up! Like Spencer, you were a big + when I started my rebuild on the RS!!

You will get it sorted out.

Maybe it is something about the Carbs? Clogged jet, loose needle, tiny hole in a diapharm?? Has to be something simple and easily overlooked!!

30064 · Feb 28, 2012

Kurt,

Take a deep breath. You need to swing back by the house for a visit. It's not the bike's fault - or yours. I'll take you up on that test ride you've been offering me. There's a solution to every problem, we just haven't diagnosed yours correctly yet.

I'm afraid if you got rid of the bike you would feel worse than you do at the time you posted your last message. You've done such a great job on that build, it's time you enjoy your efforts and labor.

I'm curious about all the oil and (grease?) in the clutch housing, was that picture taken before or after your rebuild?

-Mike V.

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