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

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Andre Litinsky
(@dretek)
Posts: 24
Eminent Member
Topic starter
 

I like the way you think Wobbly! Thank you so much. The bike was starting to look spread lol. Guess I am eager to turn wrenches on whatever I can!

 
Posted : 05/05/2019 22:13
Richard Whatley
(@wobbly)
Posts: 2416
Member
 

Thank you for your vote of confidence. The land of internet motorcycle repair often means a responder has to be part mechanic, part expert electro-mechanical engineer, and part therapist. That last one is often the hardest, because if you were on my therapist couch it would be easy to simply lean over, swat you with the newspaper and yell "Wake up !!" πŸ˜›

Yours is a common symptom. Young guys loose focus because motorcycles come apart so easily. But it's important to realize that things you can take apart in 10 minutes... may take an expert 3 hours to re-assemble. The mental line between taking apart and real, actual repair gets very blurred.

I mean really... think about it. Your car has many of the same parts, but it's NOT spread all over the garage !! :S

So lets get this thing running so we can concentrate on the actual purpose..... CHICKS ! I find, even as a religious man, that hanging a "nudie" calendar on the wall right next to the motorcycle often helps maintain this focus. You might try that.

And you'll need to build up all the momentum you can this week, because next week you'll run head first into Wobbly's 2nd Law of motorcycles: "A man always buys a motorcycle with one more carb than he's capable of tuning." But, with a nudie calendar and a 12 foot piece of 1/4" clear tubing, we can conquer than one too. πŸ‘Ώ

All the best !!

[color=blue]Don't hide 'em, Ride 'em !!
#15150[/color]

 
Posted : 05/06/2019 11:52
Andre Litinsky
(@dretek)
Posts: 24
Eminent Member
Topic starter
 

Oh, fudge.

In a combination of forcing the carb back and tightening too hard, the pipe from the air filter to the carb intake got dented and I have no way of telling if it's air tight:

I put my mouth at the bent area to see if it was air tight, couldn't really tell.

Also, when installing the carburetor, is there a particular order or to put it so it doesn't feel forced? Example: throttle cable, then air side, then engine side, then fuel?

When the carbs are just "hanging" on the throttle cables is that a good time to check the throttle valve?

Also is there a good way to get fuel hoses on the nozzles, besides from twisting. Like some lubrication or something?

T-minus 11 days til I learn to ride. Help an Airhead out!
Blue skies,
Andre

 
Posted : 05/07/2019 21:35
Edward Jones
(@14979)
Posts: 56
Trusted Member
 

A leak on the air box side is not the end of the world. Simply the carb will get some unfiltered air. As an expedient a bit of duct tape would seal.

The throttle slide should smoothly rise and drop with finger pressure. NEVER force, these are precisely manufactured components if they don't go together, find out why. Those blue hoses and worm hose clamps don't look OEM. OE hoses should slip on without undue force.

Generally a bit of heat, hair dryer heat or gun on low carefully, will soften rubbers like fuel lines to allow them to slip over nipples easier.

Sequence, attach the carb to the intake next attach the throttle cable and choke, next the fuel line. Check operation and finally install the air box to Carb hose.
But these aftermarket parts can cause problems.

 
Posted : 05/08/2019 08:40
Andre Litinsky
(@dretek)
Posts: 24
Eminent Member
Topic starter
 

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!

 
Posted : 05/08/2019 11:54
Edward Jones
(@14979)
Posts: 56
Trusted Member
 

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 πŸ™‚

Edward

 
Posted : 05/08/2019 12:24
Richard Whatley
(@wobbly)
Posts: 2416
Member
 

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.

[color=blue]Don't hide 'em, Ride 'em !!
#15150[/color]

 
Posted : 05/08/2019 13:15
Edward Jones
(@14979)
Posts: 56
Trusted Member
 

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.
πŸ™‚

 
Posted : 05/08/2019 13:38
Andre Litinsky
(@dretek)
Posts: 24
Eminent Member
Topic starter
 

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.

https://youtu.be/E1cC2jmymzM

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?

 
Posted : 05/13/2019 11:11
Richard Whatley
(@wobbly)
Posts: 2416
Member
 

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.

β€’ 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...

β€’ 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?

β€’ 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.
β€’ 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.
β€’ 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.

[color=blue]Don't hide 'em, Ride 'em !!
#15150[/color]

 
Posted : 05/13/2019 13:20
Andre Litinsky
(@dretek)
Posts: 24
Eminent Member
Topic starter
 

Wobbly I hear ya and thank ya - your response was abundantly clear! I am going to start with valve clearances and timing. I was getting antsy and took the seller's description as truth, because there was mention of timing and clearances already done. But heck, why not do it again?

It also looks like my right exhaust nut is leaking. Is this worth getting the special tool and gasket and then replacing, or hold off until I get a running bike?

I only ask because in Clymer's and pre-carb tuning research, it recommends "intake and exhaust systems must be free of all leaks".

More questions on carb syncing - later.

Thank you guys so much. I get my license this weekend. The plan is to ride ASAP!

Also, isn't there a Catch-22, where your bike must idle to get timing right? But in order to carb sync, timing needs to be perfect. My guess is: I adjust my idle screws until I can idle the bike with CHOKE UP. In essence, have the bike idle by ANY means (without flooding the engine), and then set the timing correctly with a strobe light.

I have seen a portion on static timing which requires a special tool..

 
Posted : 05/14/2019 14:46
Richard Whatley
(@wobbly)
Posts: 2416
Member
 

...because there was mention of timing and clearances already done. But heck, why not do it again?

When does it ever hurt to double check someone else's work ?

It also looks like my right exhaust nut is leaking.

You are correct. It's leaking raw fuel from leaving the "chokes" ON too long.

Is this worth getting the special tool and gasket ?

Only if you ride the bike and it still leaks exhaust gas. But first you actually need to RIDE the bike. πŸ˜› Even then you need to weigh the price of the tool versus dropping by the local shop and tipping the mechanic $5 to tighten the nut for you. The "gasket" is only replaced if it's lost. It's a simple steel wedge that's used over and over.

Also, isn't there a Catch-22, where your bike must idle to get timing right?

Either you have not read the thread suggested in my very first post, or you have not retained the information from that thread. The answer to most of your questions is right here in these 2 threads.

All the best.

[color=blue]Don't hide 'em, Ride 'em !!
#15150[/color]

 
Posted : 05/14/2019 16:39
Andre Litinsky
(@dretek)
Posts: 24
Eminent Member
Topic starter
 

UPDATE:
Today I tested my luck and see if I can get the bike to idle. I turned the air and idle screw to default 1.5 turns and tried to fire it up 5-7 times. Nothing, so I left it alone. I did accidentally leave the spark plug cap off ONE time I hit the 'Start' button. I read this can be bad for the ignition.

Moved on to adjusting the Left Valve Clearances. Intake was good @ 0.004. Exhaust was tight and I loosened it to 0.008. My question is: why does the spark plug need to be removed? Does it need to be removed on both sides? I found the OT mark on the flywheel, however, after adjusting, I realized it wasn't DEAD center looking at it straight on. I also wasn't 100% sure I was feeling the right "grip" when moving those feeler gauges.

I moved onto the right side, and no matter how much I spun the rear wheel and aligned the OT, it never seemed like the rocker arms on the Right side were loose enough to have clearance. Either that, or they were way too tight. What am I looking for in terms of the relationship between the flywheel OT symbol, rear wheel spinning, and how the rocker arms are moving in and out?

I thought this would be much easier.

I attached photos of the spark plug, clearances, OT visibility.




 
Posted : 05/21/2019 19:01
Andre Litinsky
(@dretek)
Posts: 24
Eminent Member
Topic starter
 

It turns out I was hitting TDC for the Right side, there was no clearance! I'm glad I found out. That being said, I did stick a plastic pen in the combustion chamber and a tip of the plastic pen fell in there. I am going to attempt to get it out with a hemostat and another special tool.

Next step ignition timing. Hopefully, I can get the bike to idle! At what point do I need to use a fan for having my bike idle?

Lesson learned: do not stick plastic things in the machine!

 
Posted : 05/23/2019 15:39
Richard Whatley
(@wobbly)
Posts: 2416
Member
 

The valves are not adjusted on both cyl at the same time, because they are operating 360 deg different from each other. You adjust one cyl, spin the engine 360 deg and then adjust the other.

Removing both plugs makes this spinning easier.

Rotating the engine is best done by placing the bike in top gear and bumping the rear wheel by hand.

[color=blue]Don't hide 'em, Ride 'em !!
#15150[/color]

 
Posted : 05/24/2019 00:14
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