Sunday, April 17, 2011

Zundapp Engine top end inspection

My curiosity got the best of me so I started taking things apart today. Pulled all the rocker covers and everything looks good. A little grimy but that is to be expected. The dip stick was stuck so I had sprayed it with WD-40 a couple of weeks ago. A little effort and it finally broke loose. The oil looks pretty clean but smells bad. The solids have had 30 years to settle into the bottom of the oil pan.

I decided to remove the cylinder heads to get a look at the cylinder bores. Very easy process and only needed the tools below to remove the carbs, exhaust system, rocker covers and cylinder heads. Old School Simplicity.
The right side cylinder head....pretty cruddy looking as I had it full of Marvel Mystery Oil to loosen things up. Valves don't have any visible deformities anyway.
The right cylinder bore had a bunch of crud in it. The Marvel Oil had loosened up a lot of carbon which was in the bottom. Some surface rust was present but it cleaned out easily. No surface pitting that I could see. That's great news.

The left side cylinder head was a little cleaner. Typical carbon build up. The Left cylinder bore was in great shape with no rust at all.
So far the engine looks pretty good....the push rod ends show no wear, the cylinders have no ring ridges from wear, and the cylinder surfaces look to be easily salvageable.

Good news all around.

I reassembled the engine, carbs, exhaust then filled the cylinders with Marvel Oil. I'll let her soak for a couple of months while we're out of state.... She should be ready to free up when we get back.

I'll then remove the pistons, cylinders and heads for closer attention as needed.

I now think that there is definitely hope for this project!

Regardless how far I take this project I am going to hear this engine run!

Complete restoration will be overly costly but an original runner would be fine with me.


  1. Hello,
    I wish you good luck with your restauration. I have Restaured a KS601 a few years ago, and i'm still using it. It's a very nice bike with a real good sound. I have since restaured a KS750 and now I have to rebuilt my K800 engine. Next project is going to be a KS600. If I can give you an advert, you have to check the measurement of the piston road an the cranckshft and the surface. There must be no rust at all on the crankshaft. The hard surface is only 5/1.000 mm. If there is rust on it, you may cause damages on the engine. This is the weak point of these machines. The rest must be OK.
    Best regards

  2. Thanks for the advice....the rod bearing surfaces / clearances are my major concern. I read that the rollers / cages must be indexed and reinstalled as removed. I will perform a very close inspection for any rust on the journals when I disassemble.
    Doug S.