I had the cylinders vapor blasted. In preparation, I removed the push rod tubes. After they were vapor blasted I install new stainless steel pushrod tubes I got from Euro MotoElectrics, who graciously has agreed to provide the parts for this charity rebuild project for free. I will auction this bike and proceeds will go to the Motorcycle Relief Project.
I have done this work before on my 1983 R100RS rebuild and will reference material from the documentation of that build as appropriate.
- 11 BMW 1983 R100RS Remove Push Rod Tubes & Head Studs
- 11 BMW 1983 R100RS Install Push Rod Tubes & Head Studs
I use a mandrel made by Siebenrock that I purchased at Euro MotoElectrics to remove and install the push rod tubes into the holes in the cylinders.
The push rod tubes are positioned so the top of the collar that pushes against the push rod tube rubber seal is 1.75-2.00 mm below the top of the cylinder flange. I use a machinist’s flat and a popsicle stick to help position the push rod tubes. I selected a popsicle stick that is about 1.75 mm thick. I show later how to take this measurement. You can also use a flat piece of metal instead of a machinist’s flat.
I use a tube brush to clean and burnish the push rod tube holes in the cylinders to ensure the tubes go in as easy as possible.I use Loctite 263 (Permatex 271000 equivalent) to seal the push rod tubes for an oil tight seal.
I use a MAP gas torch to heat the cylinder around the push rod tubes before I drive them out of the holes in the cylinders.
I install stainless steel pushrod tubes (BMW Part# 11 11 1 262 904) that I got from Euro MotoElectrics (EME Part# PushRodTube904)
I shot two videos of the procedure for removing the push rod tubes and the cylinder head studs, one for removal and one for installation, when I did this work on the 1983 R100RS. The push rod tubes are the same on the 1983 R100RS and 1983 R80ST.
- VIDEO: 1983 BMW R100RS Remove Push Rod Tubes And Cylinder Studs
- VIDEO: 1983 BMW R100RS Install Push Rod Tubes And Head Studs
But, I thought I could make a shorter, simpler video showing just the replacement of the push rod tubes. So I shot this video of the replacement procedure on the 1983 R80ST.
VIDEO: 1983 BMW R80ST Replace Push Rod Tubes
Remove Push Rod Tubes
You can see how to do this without using the push rod tube mandrel here.
As documented in the above material, there is a risky way and safe way to remove the tubes if you don’t have the push rod tube mandrel. That said, the safest way is to use the mandrel when removing the push rod tubes.
Install Push Rod Tubes
You can see how to do this here.
On the 1983 R80ST, I drove one of the push rod tubes a bit too far into the hole. So I flipped the cylinder over and inserted the mandrel into the top of the push rod tube and drove it out a bit until it was at the correct depth.
This is what I started with.
Here are the vapor blasted cylinders with the new stainless steel push rod tubes installed. It’s a nice improvement.