My 1st Airhead R75/6

[lake_harley]

Well, the day of truth finally came. Last item things done, like adjusting the valves (all were a bit tight), synch-ing carbs at idle, timing with a timing light (I did a superb job with my test light static setting!), and it was time for the moment of truth. Test ride time!

I had done two very short rides before, totaling less than a mile. Today's deal was to be "extended" and reach highway speeds. I was nerved up tighter than a fat girl's socks. Out of the driveway and up the road about 1/4 mile and all was well. U-turn and past my house a 1/4 mile in the other direction (no point in venturing out too far if I have to push it back) and all was still well. I had gained a bit of confidence and decided to venture out a bit farther and go a bit faster. All went well. I rode a total of about 6 miles.

Somewhere along the line the turn signal indicator quit working so I guess I'll have to go back into the instrument cluster. Also, even though the speedometer worked (got up to 65 MPH at one point) the odometer didn't move a lick. Another reason to go into the instrument cluster I suppose. Once everything got warmed up good, the idle had climbed to about 2K, so I'll need to address that. I'll just back the screws off one at a time till the idle gets back to what the book recommends, about 850 RPM if my memory serves correctly? I'm thinking I can merely back them off an identical amount and they should stay sync'd, correct? I'll re-read the manual to be sure.

As is always pointed out, unless there are pictures it didn't happen, so I offer to you proof of my first real test ride! It's amazing that a 37 year old motorcycle can bring such a thrill!

[lake_harley]

After yesterday's 5-6 mile test ride I thought it was time to get the state involved and make my new baby legal. Round trip to the inspection station, license office, gas station and a couple other detours to show her off was about 25-28 miles. Ran like a champ, with the exception of the high idle once it was warmed up, my oil light doesn't always light when the key is turned on (another reason to go back into the instrument cluster), and the brake light switch for the front brake stopped working (I just used the rear brake to demonstrate the brake light function at the inspection station).

Getting her on the open road makes me appreciate why airhead owners seem to have such a fond attraction to their bikes. It just has a "feel" that many motorcycles don't have, but yet I don't think I could describe.

It'll be fun to enjoy riding her a little now, but will also enjoy continuing to tinker with various hiccups to make it a more sound and reliable motorcycle.

Thanks to all who have helped along the way with info and tips. I'm sure I'll have more questions and updates as time goes on. Maybe, as time passes and my airhead experience evolves, I'll be able to offer input to other airhead noobs and return part of the favors.

Lynn

[disston]

High idles seem to be a more common problem these days. They were always around but I think now more common. I recently had to take the original carbs off my bike and mount my spare pair. I've used them before but never got them to work right. Now it seems the spare pair are going to be it because the originals need more work.

Check first that the problem isn't vacuum leaks around the intake rubbers.

On the new carbs I have now I notice the throttle plates don't close all the way around. They are a little crooked in the bore. I had fairly new new pieces in the old carbs. I was only able to get one of them out. So it was back to the dealers yesterday to get another shaft, throttle plate and O-ring. I already have a complete set of screws, 4, and I will reuse one plate, one shaft and one O-ring. I think I'll be able to put these on today. My complaint is the same as yours. A high idle after warm up.

Replacing #s 12, 13, 14 and 15. The spring on the right side, that is not numbered on this drawing, may or may not be on your carbs. If it is it sits on top of the slider to help it slide down a little faster.

The butterfly plates have beveled edges. When tilted in the carb bore they fit exactly. If you back the throttle speed screw off and hold the carbs up to a strong light, you may need to hold the slider up if there are springs on the slider, some carbs have this it is a popular addition to our older carbs, if no large springs on the sliders you can hold the carbs upside down, you should not be able to see any light around the edges of the butterfly, or throttle plate. If there is the plate is crooked and when the carb gets hot it hangs open more. See you tuned the bike with this in place and it seemed not a problem. But it fits less as it gets hotter. The plate sticks open more if it is not straight.

You may be able to loosen the screw and adjust the plates. This is sometimes not possible and the original screws are peened in. You need to file them down so they can be removed. What I do is I don't mess with them. I get new shafts and new plates and new screws and new O-rings. The new butterfly plates will have the correct identifying mark on them that insures you get them in the right orientation. I use Blue Locktight to put the little screws on because peening works better but causes so much trouble later.

The identifying mark? On each butterfly plate there is a very lightly tapped dot. Put there by some body in the Bing factory ages ago. This small dot goes on the outer edge on top. It is visible as the butterfly sits assembled in the carb. It may not of been there on the original carbs or if it was it is stamped so lightly that it is impossible to see now. I think it's worth checking that the ever so slight bevel I mentioned is properly aligned even after checking for the dot.

Again, look for vacuum leaks first and check for other stuff like timing or tuning the carbs, but if you are still plagued by a high idle after warm up that won't go away I suggest checking the carb butterfly plates.

[disston]

Or so goes one of my favorite theories.

Guess what I found? A missing O-ring on the idle mixture screw. This would suck air big time I guess and is probably why I couldn't turn down the right carb and the idle was high.

So I'm replacing the throttle plates and shafts anyway.

[Horsehockey]

Originally Posted by disston

Or so goes one of my favorite theories.

Guess what I found? A missing O-ring on the idle mixture screw. This would suck air big time I guess and is probably why I couldn't turn down the right carb and the idle was high.

So I'm replacing the throttle plates and shafts anyway.

Hmm. That's very interesting Charlie. I need to check the condition of my o-ring in my mixture screw on the left side....I've had an intermittent high idle issue for awhile now...

[disston]

I am right now half way through cutting the butterfly shaft out of the right carb with a file. I don't have any good hack saw blades. I have a hole saw kit I thought of using but it's much too crude to hold inside the throttle bore and cut the brass plate and shaft with out causing a bunch of collateral damage. The heads of the screws were buggered so I have to cut the dang thing out in two places so it will all come out. I hope to finish this part of this project tonight.

Going to try running the stock jets Bill.

[Big Bamboo]

High idle can also be a symptom of a sticking advance unit. One way to check while the bike is idling is to quickly turn the key off and on again without letting the bike stop running. If the idle drops, you know it;s time to remove, clean and grease the inside of the advance unit. Note: it's a very specific grease BMW recommends, available from Capitol Cycle.

[disston]

BigBamboo Brahda,

Is that the Hawaiian way, turning off the key and turning it back on? By the way I meant to tell you, I'll bet they have a Dyno on Kauai.

I think Tommy is out of Ft1v4 grease for the points cam. He was a month ago. If you call him and he has any, anybody, let us know.

[lake_harley]

All good input and possible causes to the high, warmed up idle. I'll start with the simple things (leaking boots, etc.) after double-checking the carb sync and work my way through as necessary.

On the advance unit sticking, I don't think that would be the cause on my bike since it advanced and retarded fine when timing with the light yesterday, but I'm not going to rule it out. It would indeed hold the idle up if it's sticking advanced. Easy enough to check with your method. That indeed should shake them loose if sticky.

Thanks

Lynn

[Big Bamboo]

Originally Posted by disston

BigBamboo Brahda,

Is that the Hawaiian way, turning off the key and turning it back on? By the way I meant to tell you, I'll bet they have a Dyno on Kauai.

I think Tommy is out of Ft1v4 grease for the points cam. He was a month ago. If you call him and he has any, anybody, let us know.

Actually, I learned that trick from Duane Aushermans website, saves pulling the front cover if you're lazy.... "cough" I mean relaxed and easy going, like me. Too bad about the Dyno on Kauai, I can't swim and they killed the inter island ferry system. If you really need the special grease, I can put a dab in a zip lock baggie and mail it to you for the cost of postage.

[disston]

I looked everywhere for points cam grease. There is a Mallory, Chevron and some others. Finally got some at NAPA. The guy had to look it up and order it but they did have it.

[Big Bamboo]

Originally Posted by disston

I looked everywhere for points cam grease. There is a Mallory, Chevron and some others. Finally got some at NAPA. The guy had to look it up and order it but they did have it.

Points cam grease is for the felt block, the advance unit stuff is a different animal...

[disston]

Originally Posted by Big Bamboo

Points cam grease is for the felt block, the advance unit stuff is a different animal...

Yes, you are right. I confused the two. Ft1v26 is the grease for the advance unit. Ft1v4 is the points cam grease. Capital Cycle does have the Ft1v26 in stock, that's were I got mine. They are still out of the Bosch Ft1v4 points cam grease and so is everybody else I checked with except some Porsche place that had it for $20 shipping and handling in addition to the price of ten bucks.

If you have a NAPA store near you they have an in house thick grease for points cam use. It is an Echlin product and the part # is ML-1.

[lake_harley]

I've been busy with a number of things lately and haven't ridden the /6 for a while. I did take some time, a couple weeks ago, to dig into my non-functioning oil pressure light. I had replaced the sending unit, but it once again quit coming on when the ignition was turned on. Turned out to be more loose pin/circuit board conductor strips. I should have just soldered them all when I had it apart the first time! Also checked, lubed, and generally futzed around with my odometer. I haven't ridden the bike since this last odo "service". I thought I had it fixed one time before but sticking gears and such made it add 200+/- miles to the odo total in a 5 to 6 mile ride. Maybe it didn't really have over 100K miles on it when I bought it. On the first "service", I adjusted the little drive worm gear to make contact again and thought I had it fixed, but things were so tight, the worm gear got pushed out of engagement again. Anyway, things worked much smoother turning it by hand after the second try so we'll have to see how it does on a ride.

The last time I rode the bike it seemed the engine got "noisier" after the engine had completely warmed up. Not knowing if that is somewhat the nature of an airhead, I decided to re-check the valve clearance. Left side still on the money where I set it last time. The right side was about .001" loose, but I might have had a different "feel" on that side before. Certainly not anything that would cause excessive clattering. It's at spec now. So...the question de jour is simple, do airheads tend to get noisier after they're up to opearating temp? I'll admit, I need to re-sync my carbs since it runs a bit rough at idle, but the noise, when at a fast idle and it's running pretty smoothly, is still there. I wouldn't describe it as a "hammering connecting rod" death knock....more like very loose valves.

I'd love to get this bike more sorted out so I can justify tinkering with "fun" things like building a solo seat and luggage rack for over the rear fender.

Thanks, in advance, for any feedback regarding normal airhead sounds.

Lynn

[rufusswan]

There've been so many comments lately by those that plug in some sort of music and ignore the 'sounds' .... well I'm surprised some have not weighed in.

Mine doesn't seem noisy to me, just a nice sewing machine sound. 'Course I can hear if I've mis-adjusted the right exhaust tappet too loosely. I'll bet you though that every one of them is different. Mine doesn't seem as noisy when warmed up, but if I move my head or adjust my helmet in a certain way the leg jug gets loud.

I'll wager ever damned one of them sounds different. Make sure the valve lash is correct and synch the damned carbs, and ride the thing. You will get better at both of those adjustments. Get to work on the single saddle, I had a ball last winter making mine