Re: 1962 BSA DBD34 Gold Star restoration (Nearly done...)
Thanks Maritime.
I have been moving forward anxiously wanting to start my bike for the first time, but nothing is easy. I spent many, many hours quadruple checking the tolerences, settings and timing of the camshafts, pushrods, valve train, magneto etc. My valves were checked with a degree wheel and Skip my machinist brought over his leakdown tester. The motor passed his test but there is a slight leak past the rings, but this may be OK since the motor has not been run nor have the rings and cylinder been bedded in. I will test again after it has been run in.
Skip, the man with all the cool tools.
The original carb was giving me grief but I had another 389/004 body which I picked up from E-bay last year for cheap to swap and I picked up a standard cover and screws from Mitch Klempf on my way back from Minneapolis a couple of days ago. Somewhere in a box I have a vapor blasted standard cover, but cannot find after 3 hours of searching. The new carb body is out of round and the throttle slide binds up when I tighten the main jet holder tight enough to stop gas from leaking out the bottom. I met with Skip again and we worked on it and checked the jet block for roundness in his lathe. We rigged up an external gas tank and long fuel line and again gas pissed out of the carb. We suspect the float and valve are not set right and gas is flooding the bowl and flowing out the jet holes in the front of the carb. The float was left in my parts washer for 30 minutes and it still floated with no liquid inside. We switched fuel valves but it still pissed gas. Worn fuel valve seat? Monoblocs' float height can only be changed by adding shims or washer beneath the valve holder. We added a drop of solder to the float tang and filed it flat to lower the float height. I eventually drilled and tapped the original carb body to accept 10-32 screws and rebuilt the original carb with the new cover.
With this set up the slide functioned better, but still dripped gas from the main jet holder washer when loose enough to raise and lower the throttle slide. After many, many attempts, adjustments, rechecking valve openings and closings, magneto timing, etc we still could not get her to fire up. We have ignition, compression, but cannot get the right fuel/air mixture from a leaky carb.
I am stubborn and cheap, but after spending more than two days of my life fighting a 50 year old pot metal carb, spilling and smelling gas and getting nowhere, I threw in the towel and ordered a new and complete Amal 389 from Amal UK this morning. At least a have a pile of spares for it. It reminds of George Washington's fabled axe which is original except the handle broke so it was replaced and the head cracked and it too was replaced. I guess I finally will have to polish the primary cover while I wait for my new carb to arrive.
The good news is the rain is melting all the snow and washing the sand and salt from the streets. I spent a full day last week cleaning, tweeking, changing fluids and tuning my Triton. I was going to buy new tires for her, but that money went to a the new GS carb. All she needs is a sunny day and some warmer weather and I am ready to go.