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Topic-icon New Airhead Owner - Needs Help! (Lots of Images)

  • dretek
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4 months 1 week ago #4782 by dretek
That's right, those blue hoses are as described from seller: prototype 3d printed intake boots. They seem like a very durable, yet flexible form of plastic/silicone. I will try to heat the fuel line a bit before slipping them on.

Thanks 14979!

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4 months 1 week ago #4783 by 14979
One more thing, for longevity sake, I steer way from those worm hose clamps. When giving a proper tightness they can eat into the underlying rubber and over time chew it up. I generally use Fuel Injection style clamps. The FI clamps are more expensive and have limited range but they have a solid band that will not eat up the hose.

You might try a touch of dielectric grease on those snazzy blue hoses, but you'll need good clamping. Or just get the proper size from BMW :)

Edward

1981 R100RT

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4 months 1 week ago #4785 by Wobbly
14979 told you correctly. Air leaks only matter on the engine side, not so much the air filter side.

I typically spray on WD-40, or some other light general purpose lubricant that burns easily when mixed with fuel. Those are very good lubricants for all "rubber" parts... intake hoses, fuel lines, fork boots, drive shaft boots, etc.

Heat from a "heat gun" might be OK, but heat from an open flame would be forbidden due to fire hazard.

Don't hide 'em, Ride 'em !!
#15150

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4 months 1 week ago #4786 by 14979
OMG!! NO OPEN FLAME!!!!!! Gee I wouldn't think that would need to be said when working around gasoline and many other only slightly less flammable motorcycle stuff.
:)

1981 R100RT

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4 months 2 days ago #4810 by dretek
UPDATE: I installed the carbs, rotated the air-mixture screws 540 degrees (1.5 turns) out from all the way tight, idle screws was a guess, and then fired her up!

She was idling at 1025 RPMs and it sounded really nice, so the idle screws and mixture were left ALONE. However, the bike was only able to start with the Choke Lever: DOWN, which makes me think it was running rich.

After revving the throttle and adjusting the screws a bit, the RIGHT carb spat some fuel, shortly after, there was loud popping from the RIGHT exhaust, and then leaking at the exhaust nut. The bike dies when revving high. It felt like the right side was running too rich or something.



I did borrow a timing light and Uni Syn from my co-worker. Maybe I can sync the carbs with the Uni Syn and make sure valve clearance and timing is correct?

I was going to use this: http://www.vintagebikebuilder.com/mikuni-tuning-and-jetting-guide.html as a guideline for carb syncing. It does say I need to short the spark plug with a spare one. Does this mean you are syncing ONE side AT A TIME?

Overall, I'm not sure what to be doing, perhaps it's time for a mechanic?

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4 months 2 days ago - 4 months 2 days ago #4813 by Wobbly
That's for the video. That helps a lot. Some thoughts that will hopefully correct your thinking in several areas....

However, the bike was only able to start [by] running rich.

• All engines generally need a rich mixture for Starting. So your experience was not special, but rather standard operating procedure for every engine in the world.

It felt like the right side was running too rich or something. Choke Lever: DOWN...

• Your Mic carbs DO NOT have "chokes". A choke restricts the air entering the engine, thereby forcing the engine to suck in more fuel.... thereby making a rich mixture. Opposite this, your Mics have an Enrichening Valve which FLOODS the intake with raw fuel, whether the engine wants it or not. Yes, it achieves the "rich mixture" the engine needs, but it does it via flooding.

So the difference is that a choke is more like sucking a soda up through a drinking straw, whereas the Enrichening Valves are more like opening up a kitchen faucet WIDE OPEN !!! Do you comprehend the difference ?? So as soon as your engine starts, within 10-15 seconds you need to lift those Enrichening Levers UP and close those flood gates.

If you don't understand anything else, understand this.... IT'S SIMPLY TOO MUCH FUEL !! You are killing your engine. Absolutely don't allow those valves to stay ON. As soon as the engine starts, then turn lift the levers to the OFF position. In a nut shell what I'm saying is that the problem is not the carbs, but instead the way YOU are operating the engine.

Maybe I can sync the carbs with the Uni Syn and make sure valve clearance and timing is correct?

First of all you were advised to set the valve clearances as one of the first orders of business. Secondly, you can't do ANY meaningful carb adjustments until timing, ignition parts, and valves are perfect. Carb adjustments, being dynamic, are the very LAST adjustments made. And they shouldn't be even attempted until the bike is fully warmed up... as in ridden 10 miles. Then you're going to need a big cooling fan going while you work on the engine. I don't see a fan in your video.

Does this mean you are syncing ONE side AT A TIME?

Everyone in the world syncs one carb at a time. Synchronization is by its definition is the act of going from one carb to the next. However, the stock carbs DO make this task much easier, and much faster. Just like the stock carbs allow you to trim the enrichening down to 50% or 25%, those Mics narrow your service choices considerably. So YES, it's going to be more difficult, but not impossible.

Overall, I'm not sure what to be doing, perhaps it's time for a mechanic?

• I would say that all learning is struggle. If you are having difficulty, then it is because you are learning. I would say take it to the mechanic and let him learn only if you are sure you won't get 200 miles from home and need some of that knowledge.
• I would also warn that not many motorcycle mechanics today know anything about carbs or Airheads. So basically, they'll be learning what you need to know... while charging you a lot of money.
• Additionally, WHERE would you take it ? Back to the person who couldn't figure out the Bings and installed the Mics? If they couldn't repair the original stone-ax-simple Bings, then I surely wouldn't trust them with any other carb !!

All the answers are here. You decide.

Don't hide 'em, Ride 'em !!
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Last edit: 4 months 2 days ago by Wobbly.

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