Obstacles on the road #1

Finally got the engine mounted and the bike up and running. Started easily, and sounded good, and the white smoke from before seemed to be gone, at least when it was idling.

When it was running however, the story seemed to be another one.
Then it would smoke a bit again, even though not as much as before.
The engine also seemed to be bogging at times when accelerating, and after having accelerated to a high speed and making a quick halt, it would often die on me.

Tried various settings with the carburetor, adjusting the idle screw and air screw, but without much luck.

The mechanic (Erik Ludvigsen, his contact details can be found on the FAQ site) that helped me before came by, picked up the bike, and brought it to his repair shop, in order to take a closer look at what might be causing these issues.

He soon concluded that the carburetors main jet needed to be a few sizes larger, and changed it from size #62 to #70, adjusted the idle screw and air screw, and delivered it right back to me. He even suggested to change the standard 13 teeth front sprocket to 14 teeth. This should lower the RPM’s a bit, while also giving a slightly higher top speed. As a downside it would cause the bike to accelerate a (hopefully tiny) bit slower, but it was a trade-off I could easily accept, knowing that it would put less stress to the engine.

This guy really does a great job, and sometimes gives you more than what you’ve been asking and paying for. The first time he received the engine, he decided to give the engine head a nice makeover with some bead blasting, here are two pictures to show how it looked before and after:

I got the bike back just recently, and it runs a lot better now – and a lot faster too. The smoke has disappeared when it’s idling, and it’s able to idle quite low now as well. Earlier it was running around 45 km per hour, and now it runs 60 km per hour, quite the difference.
Here’s a few pictures from my ride after the new adjustments:

It was great fun to ride it, and I really enjoyed the trip. I did however still experience a few issues, that’ll need to be resolved.

  1. Starting and driving
    The engine is very easy to kick start, even with a cold engine. If I close the choke lever as suggested when starting it cold and open the throttle just a tiny bit, it seems to drown. I at least need to open the choke lever once again, kick it over a few times with the ignition turned off, and then it starts fine afterwards.
    When driving at high speeds, and the engine has been operated for let’s say 15 – 20 min., it’ll also sometimes still die on me when making a quick halt.
    If I’m at a standstill and opens the throttle half a turn, it’s as if the bike hesitates, trying to decide whether or not it should live or die, and then finally decides to live on for yet another day, and starts running.
  2. Carburetor
    There’s all of a sudden gas leaking from the carb.

Fuel level seems to be too high in the carburetor bowl somehow, don’t believe that it should be all the way up to the air screw.
I also have an idea about the main jet being a tiny bit too big, since it seems to be drowning quite easily.
I should be getting a visit from the mechanic one of these days, and we will try to look into it together. To be continued.

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