I’m getting close to the end of the assembly of the bike. One of the last little projects is the installation of the carburetors, air box, air tubes, choke lever assembly and cables. You can read about this work here:
Although this is not complex work, it always seems to take me more time than I antipate to get everything assembled neatly and route the cables so there is minimal resistance.
I ran into a small problem aligning the throttle twist grip with the cam that pulls the throttle cables. I had to advance the registration marks from the 9:00 position to about 7:00 or there wasn’t enough slack in the cable for the carburetor butterfly to be completely closed. I had to replace throttle perch and and cover on the right handle bar with the newer version which has a longer path for the cables and chain on the cam.
With this done, I’m very close to the first engine start after seven years of hibernation.
Here are a couple of the pictures from the write-up.
Installing Tank to Tee and Cross-over Fuel Line
Choke Lever Parts
Choke Handle Installed in the Body So Teeth Engage Cable Rack Teeth
aption id=”” align=”alignnone” width=”640″] Choke Body and Choke Cables Installed on Left Air Box Cover[/caption]
Left Carburetor, Bushings and Air Tube Installed
Carburetor Vertical Alignment
From the Saddle View of Carburetor with Cables Installed
At long last, I’m ready to install the top end (pistons, rings, cylinders and heads) on the engine. Previously, I bead blasted the cylinders, measured the bores for ovality and taper, ground the ends down on new 0.5 mm oversize rings to get the correct end gap and had the heads rebuilt by Randy Long. The parts have been sitting in boxes patiently waiting while I got the engine and wiring back into the frame.
I had an adventure along the way with a new tool, a ring expander. Earlier in the project I used it to remove the rings and decided to use it to install them rather than use my fingers as has been my practice in the past. But, as I was “playing” with it with the the oil control ring, for some stupid reason, I squeezed the expander repeatedly to see how well it worked. If you expand a ring too much, you get this result. 🙁
Too Much Expansion Gets You a Broken Oil Control Ring 🙁
That cost me about $70 with tax and 2 weeks of lost time. This is yet another one of those experiences when I want to take a mulligan on what I just did a second ago :-).
Another surprise is the way the cam shaft and cam follower are aligned. I hadn’t expected the follower to be offset from the center line of the cam lobe, but it’s over about half way.
Exhaust Cam Showing Off-center Cam Follower
This is done so the rotating cam lobe causes a torque on the cam follower making it spin and in turn, spinning the push rod. The idea is to have even wearing of the cam lobe, the follower and the push rod. I was aware that the rocker arm tappet causes the valve to spin for a similar reason, but I wasn’t aware the same thing happens in the bottom end.
I followed Oak Okleshen’s documentation, “Manual 1: Boxer Top End Disassembly, 1970-1975” and “Manual 2: Boxer Top End Reassembly 1970-1975” available directly from him for a modest fee.
Email: “askoak” at “aol” dot “com” Address:
Oak Okleshen #35
22637 S. Ridgeway
Richton Park, IL 60471
It covered an issue with aligning the rocker arms correctly on /5 heads that I was not aware of before. And, it has a lot of details that should help you stay out of trouble, if you don’t decide to “play” with your new ring expander 😉
Here are a couple of the other pictures from the write-up.
Progress So Far-Ready To Install Engine Top End
Cam Appearance on Compression Stoke
Applying Light Oil Film on Inside of Cylinder Bore
Inserting Piston in Cylinder with Ring Compressor
Correct Left Side Piston Orientation with “Vorn” Pointing to Front
Hylomar on Engine Case
Frozen Wrist Pin and C-rings
Aligning Push Rod Tube Rubber Gasket in Engine Case
Left Side Rocker Arm Assembly with Push Rods
Proper Orientation of Rocker Block (Slot Facing Outside of Head) and Nut Boss on Face of Block
At this point, with the exception of the rear fender and the attached turn signal and brake light assembly, I have everything installed in the frame that the wiring harness connects to. Thanks to a lot of pictures I took during the general disassembly of connection details and wire routing, putting it all back together was pretty straight forward.
Here are a couple pictures for the many I included in the write-up.
Broken Wiring Harness Sheath
Corroded Lug on Starter Relay Wire to (+) Battery Terminal
Engine Wires Attached to Starter Relay
Attaching Headlight Shell Gaskets
Mounted Headlight Shell
Threading Main Wiring Harness From Headlight Along Frame Backbone
Routing of Right Control Perch Switch Cable From Headlight
Starting to Pull Rear Frame Wiring Branch Through Rear Frame Tube
Thanks to Bob Fleischer, again, for tips and tricks and to Duane Ausherman.
I found a nifty template from Scott Lydiard (BMWScotter.com) that helped get the front brake levers aligned correctly on the brake levers. Scott’s site is having some problems but he was kind enough to provide a PDF of this template that I provide a link to in the write-up. Here’s a picture of the template.
Scott Lydiard’s Brake Lever Alignment Template
You can cut it out and use it with the brakes installed.
Using Scott Lydiard’s Front Brake Lever Alignment Template
Here are a couple more pictures from the write-up.
Front Brake Carrier (Front to the Right)
Front Brake Assembly
Front Brake Arm Cam with Lever and Adjustment Cam
Front Spring Installed and Shoes on Pivot Pins
Attaching Rear Spring Using Vice Grips
Front Axle with Spacer Sleeve
Connecting Front Brake Torque Arm to Brake Carrier Stud
Brake Cable Assembly at Right Control Perch
Inserting Ferrule in Rear Brake Lever to Capture Outer Sleeve of the Cable