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

[andrelitinsky]

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 gages.

I moved onto the right side, and no matter how much I spun the rear wheel and lined 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.

[img size=380]https://i.imgur.com/GfQA3pN.jpg[/img]
[img size=380]https://i.imgur.com/lETQ6Eu.jpg[/img]
[img size=380]https://i.imgur.com/qZhVhCb.jpg[/img]
[img size=380]https://i.imgur.com/VhBBjy2.jpg[/img]

[Matt Chapter]

Top dead center for each side is 180 degrees from the other; when one side is there the other is not, so you'll have to go around again.  The reason to remove the spark plugs is that if you didn't, you'd be trying to start the motor akin to a bump start, but by hand.  This is difficult to do, to say the least.  That spark plug looks a little dark / wet, but diagnosing spark plugs over the internet is mostly speculation.

I believe that your carbs are well out of tune at this point.  Given they are not OEM, you'll want to find some documentation about how to tune them.

[mrclubike]

Instead of  using  the back wheel to turn the motor over
Drill a 5/8 hole in the front cover to be able to insert a 6mm hex wrench into the rotor bolt and turn it over that way
then plug it with the same size plug for the timing hole
Or you can just remove the front cover
But you still have to remove the spark plugs to relieve the compression

When the timing mark is at OT
The piston can be either at top dead center "compression" or in "cross over " 

You want to be on TDC compression when you adjust the valves
This  is indicated by the vales not moving as you go thru TDC

If you are in Cross over the Int and Ex valves will move as you go thru TDC 

OT = TDC

I would set them at .006 and .010

[mrclubike]

If you remove the front cover disconnect the battery to prevent shorting out the diode board under it as you remove  the cover

[andrelitinsky]

I was able to get the valve clearances spot on (within .001" tolerance).

Now the next step is to check timing right? But to do that you need the bike to idle. The weather was warm and I was feeling good, so I decided to fire her up.
After 4-5 tries of different combinations of: having fuel enrichment OFF/ON, backing out idle screws and air mixture I was able to get her to IDLE with enrichment OFF.

The bike ran with: Fuel Enrichment: OFF (Lever UP), 1.5 turns out Idle, 1.5 turns out Air (note these are Mikuni VM34s)

I did see some smoke come from the right exhaust nut area.
[video]https://www.youtube.com/watch?v=36KDXI4ZksE[/video]

Also, I was able to hear a bit of "clacking" in the cylinder head. I am not sure if this is okay, or me naturally being concerned?
[video]https://www.youtube.com/watch?v=YOiF5WGfj3M[/video]

After turning the bike on again, I noticed the RIGHT EXHAUST is SIGNIFICANTLY hotter than the left. Almost as if the Left side isn't running.

When trying to throttle a bit, the bike shuts off.

Am I ready to set timing now that the bike CAN idle? Do fans need to be placed?

Any thoughts or suggestions would be greatly appreciated.

Blue skies,
Andre

[mrclubike]

What does your ignition coil look like
Take a picture and post it
If it is original it needs to be replaced

Since you have an electronic Bean can chances are the timing is OK unless the advance is stuck at full advance   but it should still run
And yes the bike needs to run thru the whole rev range to check that the advance is working correctly but it can be set at idle or at 4000 rpm depending on the timing mark you use
if you cant check the timing quickly yes fans are a good idea

Yes valve train noise to a certain level is normal but some of it can be caused by to much rocker arm end play

It also sounds like you have a dead cylinder
If one is hot and the other is not
If so that has to be sorted out before you can tune it

And finally I think you may  need to get some local help   

[andrelitinsky]

Thanks for the responses guys. The bike is able to start with Enrichment: ON.

However, I need to give it some throttle and rev to about 2-3k rpms to keep it alive.


If you notice in the video, the left side is popping and there is light coming from the intake side. What do you think is causing this?

[media]https://youtu.be/T03MEgj2_kI[/media]

You can see the light coming from the intake here. Is this the arc from the spark plug or actual combustion?


I will take a look at the ignition coils once more.

I will also do a valve clearance check and do a compression test.

[Bob_Roller]

The light you are seeing on the intake tube, is combustion,  the intake valve is opening and there is still open flame in the cylinder, it ignites the fuel air mixture in the intake .

Here's a link to a site that has Mikuni tuning info on BMW bikes .

https://www.tapatalk.com/groups/airheadtechforum/tuning-mikuni-slide-carbs-t394.html .

http://iwt.com.au/mikunicarb.htm

You also need a manometer to get the carbs synchronized, I don't think tuning by ear is going to work here .

[tunnelrider]

Synchronising the carbs is a step after having a basic idle.  Perhaps the carbs are set either too rich or too lean, an indicator would normally be if the bike can start ok without the choke  = a rich mixture but worried the oil leak from the exhaust could be a sign of more serious trouble, i.e uneven compression.
Take it to a mechanic if you're out of ideas.

[tunnelrider]

Hi Andre,
In my experiences of tuning the R65 once the valve clearance has been set right it should start easily.  Since you're having trouble starting after setting the clearances for the first time it may pay to revisit it if you didn't turn the engine 180 deg before setting the other side.  I've usually used the back wheel for TDC personally and yes it's impossible to do without taking the plugs out.  When setting the clearance with a feeler gauge, the correct feel is apparently like putting/pulling the feeler gauge into the middle of a phone book (if you can remember what they are, seem to be getting rarer these days ), so a slight drag is what you're after.
Next I would ground the spark plugs on the cylinders (tape them down so the plug outers are earthed against the fins) and check for symmetrical and regular sparking.
Bob gave a time saving link to set up the mikuni's, they should have an initial setting, if the bike won't start with those settings, check fuel supply.
If all this has been done already, hire (from a good garage) or buy a compression tester, ground the plugs and use the tester with the throttle fully open.  Both sides obviously should be approx the same and at least 100psi.

Lastly have you checked that the air filter is not blocked?  Also that the sparkly blue carb manifold rubbers are clamped air tight and no rips or leaks in that bling.
All the above are the basic essentials.