Monday, September 5, 2011

Stuck Pistons, Volume 2

Before spending 12 weeks in Arkansas this summer I filled the cylinders with Marvel Mystery Oil and let them sit. A week ago I pulled the heads and related pieces off in an attempt to "free" the pistons in the bores. I found that a lot of the oil had seeped out so they were no longer full of oil. I worked the transmission into high (4th) gear and rocked the rear wheel in an attempt to move the pistons but to no avail. I then used a wood dowel and gave each piston head a little "wack" to hopefully shock the rings free but again to no avail.

I reassembled the engine top end and left out the push rods this time to assure no valve openings to loose more oil. I filled them to the brim with Mystery oil through the spark plugs and sealed her up for another soaking session.

This time I removed the carbs, air tubes, exhaust system and all related parts to speed up the tear down next time. I labeled everything and stored the pieces in a sealed container.

I've been monitering oil loss this time and things are holding well. I added maybe a couple of ounces to the left side cylinder today and the right jug is still full.

The Zundapp Pistons each have 5 piston rings on them so I have been told so there are more rings / rust holding onto the cylinder walls. Hopefully a few weeks of soaking will free things up.

The other day I removed the hacked up shifter linkage which was on the bike and installed a nice original ($80.00) linkage assembly. This "new" linkage has a bit of surface rust to be removed but it is in nice condition. I also found a reproduction headlight ring on EBay a while back. I haven't installed it but it appears identical to the beat up, dented original on the bike now.

Saturday, April 30, 2011

Zundapp Factory Photos - mechanical

An early Zundapp Advertisement for the "Autobahn" capable KS500

Engine "ghost" photo. The Cam Gear & Oil Pump Gear are a fiber type material. A well known Zundapp guru tells me these gears last quite a long time. He has seen ones from the 30's still in good usable order.

The "Bing" carbs. Similar to those used on BMW's and other motorcycles.

Rear "ghost" view of KS601 Engine

The chain assembly in the transmission. These are very robust and long lasting.

Front fork assembly

Plunger rear suspension. Some upgrades were available for these back in the day.

Zundapp Final Drive Assembly

Another front end photo.

Zundapp Coversion?

I got this photo of a Corvair Converted Zundapp KS601 from the ADV site. I think it still utilized the original Zundapp transmission so that somewhat attests to the strength of the transmissions.

The frame was stretched out quite a bit to stuff the 6 cylinder boxer motor in.

The Zundapp Transmission chain configuration. I have a friend who had ridden one years ago and he said it felt like a rubber band. The manual shifter engages a system which automatically shifts the gears, The lever does not directly link to the gear set.

If for some chance my Zundapp engine was completely shot I might entertain the thought of a BMW engine coversion. I have the 1982 R65 which could be a potential donor but.......I'd hate to destroy one of the few remaining KS601's. If I did do a conversion it would have to be reversable to the original drive train.

Monday, April 25, 2011

Let the "bleed" begin.....Zundapp Style

The ultimate my opinion. The Zundapp KS800. Four cylinder flathead engine. Manual hand shift. An Art Deco work of art.

The KS600 Hand shift. This bike has the same foot lever / linkage as the KS601 but also utilized a hand shifter along the tank.

While the engine cylinders soak I've been scrounging up a few misc. parts via the Internet.

Found this 50's NOS 6 Volt horn over in Greece for cheap. Not a KS601 original but the price sure was right. It is around 3.5" diameter so should fit where the original lived. I'll need to bury it in the backyard for a few months so it matches the rest of the bike.

My gas cap is dented up pretty good....this original KS cap has a few less dents. It was a $5.00 purchase.

My KS has one "ball tip" lever and one short spear type lever. I bought the shorter of the two here so I have a matching duo.

Someone in the past has hacked up my linkage. It still functions but the proper pins were missing and the linkage pieces had been split. This replacement linkage is the most expensive item on the page.....but this will get things back in order. The KS600 had both a foot shift and a hand shift lever. They ran a rod from the right side linkage up to a tank side hand lever. Maybe I'll copy that design and rig up a hand lever. I think that would be cool.

One proper Bing carb screw to replace a BMW idle screw which was improperly fitted.

These are the proper pins needed to affix the new shifter linkages.

I'm missing the front upper fender brace. This brace comes with a nasty old "bobbed" fender. I'll remove the brace and refit it to my fender. I do have some old school aluminum fender struts but preferred the original ones.

This is a clutch linkage tensioning spring. My clutch / brake cables are shot. I found an outfit that supplies cable kits which allow the builder to manufacturer their own cables...I'll give it a shot.

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.