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ricksr17
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VBMWMO #9198
Florida Panhandle
Joined: 11/15/2016
Posts: 5

I have a fully restored 1928 R62. Have ridden it a total of one day. Still a little confused with the operation of the spark advance (left lever) and air slide/choke (right lever). A basic explanation would be great.

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Darryl.Richman
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VBMWMO #6285
Surf City, USA (Santa Cruz, CA)
Joined: 10/27/2006
Posts: 2183
Your R62 works the same way

Your R62 works the same way as my R52, which I've ridden across the country twice on the Motorcycle Cannonball. I'll give you some advice this evening, no time at the moment. However, do look at my hands in the photo below:

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Darryl.Richman
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VBMWMO #6285
Surf City, USA (Santa Cruz, CA)
Joined: 10/27/2006
Posts: 2183
Ok, here goes. Basically,

Ok, here goes.

Basically, everything that you expect the motor to do automatically, you must now do manually.

On a modern bike, for example, anything built by BMW since WWII, when the motor speeds up, an automatic spark advance operates and makes the spark timing happen earlier on each cycle. You do this manually with the thumb lever on the left side. When the lever is completely forward against the stop, this should be the most advanced timing. When you swing it back, the timing gets later and later (more retarded) in the cycle.

When you kickstart the bike, you want to retard the timing all the way. To keep the engine running slowly, you want to keep the timing retarded (such as when you want to idle, as at a signal). When the motor accelerates in each gear, you want to advance the timing. When you are cruising down the road, assuming that the timing is setup correctly, you'll advance the lever all the way to the stop.

The top lever on the right side is the choke. All the way forward is fully choked, all the way back is fully open. I use this to choke down the air when I start the bike, to richen the mixture. The Handbuch advises choking it down a bit when the motor is under a heavy load, such as climbing a steep grade. I also use it to further slow the motor when I am stopped at a signal.

The bottom lever is the gas. Forward is slow and back is fast.

My experience:
To start from cold, I open the tap and hold the tickler on the carb for a count of 8. Yes, 8. Then I fully retard the spark, open the air about 1/4 and the gas about 1/3, and kick. It nearly always lights on the first kick. *Immediately*, I close the gas to < 1/4 and open the air to about half. It will fast idle with the spark retarded. I let it warm up for 30s - 1m before putting any big load on it.

To move away, I advance the spark lever so it is about 1/3 back from the stop, open the air fully, clutch and put the lever in 1st, give it some gas and let the clutch out.

If you have an original transmission, you need to double clutch whenever you shift into 2nd (from 1st or 3rd). The later R11 transmissions don't need this because they have a constant mesh configuration.

To shift to 2nd, close the gas, clutch, shift to neutral, release the clutch, blip the gas, pull the clutch and, when you know* that the motor and wheel are at the same speed, shift into 2nd and release the clutch as you give it more gas.

*) You don't know. But, you get a feeling for it after a while, and the awful grinding gradually goes away. Here's a video of me doing this:

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ricksr17
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VBMWMO #9198
Florida Panhandle
Joined: 11/15/2016
Posts: 5
Spark Advance, THANK YOU!

Darryl,

THANK YOU! What a superb response. I greatly appreciate your detailed reply. The way you described it really makes sense. Can't wait to give it a try. I'll have to share my story with you someday about this motorcycle ... it's a pretty neat story. Really glad I joined the club!

Have a GREAT day!
Rick

  • 28r62ride.jpg
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Rick Sr

Darryl.Richman
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VBMWMO #6285
Surf City, USA (Santa Cruz, CA)
Joined: 10/27/2006
Posts: 2183
I would love to hear your

I would love to hear your story, and possibly share it with the club in the magazine.

These bikes are surprisingly rideable, once you get used to them. I won't say that I ride mine every day, or even every week, but it is ready to go and I don't have any problem choosing it to go for a ride.

Good luck with yours!

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http://darryl.crafty-fox.com

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