Wednesday, March 30, 2016

How's the Rig Doing?

I received this inquiry today from Dom in email and thought that I may as well write a short post answering the question.

When the carbs were initially installed, it felt like the throttle cables shrunk somehow and even after backing out all of the cable adjustments they seemed to be barely long enough. This seemed odd but I sort of managed to get the carbs balanced. I was anxious to hear it run. After riding around yesterday, the engine would only slowly return to idle. This suggested that the throttle wasn't resting on the idle stop screws. By the afternoon, I also noticed that the left cylinder head temperature was consistently much higher than the right and the exhaust sounded "off". My hunch was that the left cylinder was working harder than the right due to unbalanced carbs.  Last night, I pulled the throttle cables off the bike and after messing around with the splitter, they seemed to be a be a bit longer. After reinstalling them, I checked both carbs and now there was slack in both throttle cables as there should be.

After starting the engine, the idle speed was too low so I adjusted it up using the idle set screw on the right carb. Using the TwinMax, I then adjusted the idle set screw on the left carb until it indicated that they were balanced. After making sure that there was still play in both throttle cables, I tightened the cable down that had less slack, twisted the throttle to about 2500 rpm and adjusted the cable on the other carb until the TwinMax indicated that they were balanced.

On this mornings ride, the engine was very smooth, and ran better than it ever has before. Almost no vibration, quiet and sounded like a sewing machine just like a boxer should. It felt really good riding around trying to follow the break-in procedure listed in the manual. Now that the engine has been running some (80 km) and the oil filter and passages were full, I checked the oil level again and added about 150 ml to get it up the "full" mark with the dipstick not screwed into the block. Oil capacity is now around 3 1/4 quarts. I like that better.

So I'd say that the rig is doing good so far. No oil leaks. Starts on the first revolution. Smooth and quiet. Clutch feels good. I like the new location for the reverse lever. And I'm tending to run the engine at higher rpms. Now that I know how the lubrication system really works, I don't simply shift into a higher gear when the load is light. E.g. in the past, I would shift into 4th when cruising down the road at 35 mph. I figured, no load, why not. Now, I'll just leave it in 3rd and not go to 4th until mid to upper 40s. The engine needs RPM to keep oil flowing.

No pictures as I couldn't think of anything appropriate. No blue skies or pretty white snow. Just rain, sleet and black ice. 


  1. Great news and update.....good to hear you got the cable slack you wanted on the carb cables. I too, used to shift into fourth when below 45-50mph, but these engines prefer to rev high so now I usually don't shift into fourth until at or above 50 mph. Scarlett seems happier when I do this.

    1. Before, I figured that there should be sufficient flow to keep things lubricated at lower RPM as long as there isn't any stress on the parts but I'm not convinced. RPM is important.

      I couldn't figure out why I needed to mess around with the throttle cables. But it works now...

  2. I'm confused. Must be all the moving to Toronto distractions.

    You and Dom both have BMUral franken-bikes now??? Not unless the Ural is a boxer?

    1. Any engine that is horizontally opposed is referred to as a "boxer". The old air cooled VW, the air cooled Porsche, Subaru, Honda Goldwing, BMW R bikes and Ural. But Toronto could be distracting you too!