engine build - slowly but surely
I found some pics of the oil manometer in use on a 1974 BMW R60 I had about 3 years ago. I had replaced the Bing carbs with Mikunis, and they had a boss on the carb for vacuum fittings, so I installed a pair.
The manometer is made from a wood yardstick, 12' of vinyl tubing and some screws/clamps to affix the tubing to the yardstick. I then used some 20W motor oil I had, and filled the tubing to approx the 18"- 22" level in the yardstick; it's easiest to do with a syringe, but still bubbles can get in - just warm it up with a hair drier. Always attach the tubing to the carbs with the engine off - same for removal - otherwise, the vacuum will suck the oil into the engine if you remove one tube with engine running - been there, done that. I sync the carbs at cruising rpm, not idle, because the mixture is controlled by fixed jets/ slide needle position. I then let the engine idle, and adjust the sync with the mixture screws - you can't just set the mixture screws out at, say 1 1/4 turns, because there are a number of variables/tolerances when the air screws, seats, etc are manufactured, or if someone has cranked the screws down too hard and distorted the seat. I've found this method to work quite well, as you want a smooth engine at cruise. This is especially noticeable on fours. I've seen many sync the carbs at idle, with the idle mixture screws all out the same, and then wonder why the engine is not smooth at cruising. It takes more time on a four- on my Kaw, I had to sync the left pair, the right pair, then the two pairs. Once done several times, not hard to do, just more time. It is amazing how sensitive the manometer is, as the slightest adjustment will have a noticeable change in the oil level, so much so, that adjustments had to be made with the mixture screws or the cable adjusters always moved either all clockwise or all c'clockwise. When not in use, I cap the vinyl tubes w/ golf tees.
Dick
My 4-tube manometer just had all 4 tubes mounted to a single maifold and was mounted on a 4 or 5 foot plank of wood. I used 1/2 inch clear tubing so there was plenty of inertia and the common manifold meant that each reading was pulling against the other three. Never thought about using oil. The water could be emptied after each use. Preety cheap unless you use Perrier...... G
'60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160 '66 Matchless 350 '67 CL77 '67 S90 '77 CB400F
Just a small mod to the swing arm. I've got some 1/8 x 1" Delrin [acetal resin], so I made a small plate for the underside of the S/A. I took a small clean-up cut on the surface to eliminate a couple weld high spots, and tapped the holes 8-32. I noticed on all three swing arms that I have that the chain has left some marks on the paint - don't want this for the new powder coat it will get.
Still needs media-blasted.
Dick
Water is 25% more dense than oil. Even with the long columns I had to be careful not to blip the throttle too hard as it would turn into a water injection kit..... :-) G
'60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160 '66 Matchless 350 '67 CL77 '67 S90 '77 CB400F
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