buffing wheel

Gear Shift Fork Spindle Polishing

Symptoms:

The repair described in this page applies to the A1 and A2 (and possibly others) gear shift fork spindles. This is an easy, but important job once you have opened up your motor.

I owned my A1 for eleven years. During most of this time, I had no idea how a Heinkel was supposed to feel when shifting. When shifting, the gear shift lever would bind and it was extremely difficult to force it into second gear. Initially I thought the problem was due to the Magura shifter assembly. After a good cleaning and greasing, I dismissed that cause. Other people thought the problem was caused by interference between the clutch cover and the shifting gear.

When I finally opened up the engine, I discovered the true cause of the problem. The polished steel spindles that hold the gear shift forks were corroded in all of the positions but neutral. I suspect this bike sat in a moist environment for many years.

I was able to polish my gear posts. But if yours are really bad, you can obtain spares from the Heinkel Club Deutschland.

Repair Time: 1 hour. (Once the pieces are removed from the engine.)

Tools Required:

Repair:

Before polishing photo.

Remove spindles. If you are rebuilding your engine to renew the bearings and seals, you have already removed these two pieces. The spindles allow the gear shift forks to slide back and forth when changing between gears. In my case, there was considerable friction when sliding the gear fork on the spindle. Look at the picture, you can see the corrosion.

Remove gear shift forks. Both ends of each spindle have a circlip that keeps the gear shift fork from sliding off the end. Remove both circlips.

Sand spindles. Depending on the level of corrosion, begin sanding the spindle with wet/dry sand paper. My spindles were so bad, I began with 320 grit (coarse) and progressively made my way to 1500 grit (extremely fine).

Polish spindles. After completing the sanding, I used my buffing wheel to polish the spindles.

Polish gear shift fork inners. The inner diameters of the gear shift forks weren't really corroded, but they were dirty. For good measure, I wrapped a little sand paper around a cylindrical tube and cleaned up the shift forks. Then, I used my dremel and jeweler's rouge to give them a nice polishing.

After polishing photo.

Assemble gear shift forks and circlips. I wiped down each piece real well, and then inserted the spindle into the fork and secured the circlips. There is no right or wrong direction here. Once assembled, I greased up the spindles real well to test the lateral friction. Smooth as silk!

Install assemblies. I've found the easiest way to do this is to insert the fork into the gear groove, then twist the gear change control cylinder until the gear fork pin finds the notch in the cylinder. Once this is done, I rotate the cylinder until the gear shift fork spindle can be moved to its hole in the engine case. This is hard to describe, but once you see how everything works, you will agree with me. Really!

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