ChuckyShamrok wrote:Thanks, the Points part is screwing me up, I'm 27, haven't had to really work on cars with points OR carbs. I have a weak spark that will occasionally fire a cylinder off, but more often than not won't. Carb wise I'll check the fuel level in the float bowls. I set timing using a ohmmeter to set the points. I spun the engine to the S mark on the flywheel and than checked the points, which are open at that point. I set the gap at spec. Still have a weak spark. battery voltage at power wire going to the coils. I have a set of points and a condenser on order, as I figured I would rule those out cause they're cheap. What scares me basically is the previous owner has had his hands in various parts of the bike, and it worries me he may have done something weird.
Thot that might be. What I know about magnetos you could engrave on the head of a pin with an axe---but I don't have to deal with one or I'd take a day and learn it. Big upside to that bike is there is a tremendous mount of documentation and the issues are known. one special one for that particular one is if you have old /5 style switchgear or the newer WTF-were-they-thinking? kind. Pretty different wiring diagram with important changes in the starting system. But carbs or FI, pulling a plug to check for some gas on it is all the same. Sparks is sparks be it points and coil or Electronic pickup and HEI. The latter bites harder but a limp yellow spark and it won't run right. Ought to run tho' If it''s very cold in your shop then more trouble. Starter fluid.
The chokes on the carbs may not be overly functional. Diagnose with starter fluid. If it runs on the spray but not on the carbs, you got a fuel problem, right?
if you are serious about keeping and wrenching it, I would buy 3 books. The charging system manual from Mottorad Electrik. $23 or something. The Bing carb manual from Bing Agency International. $11 shipped. And the old VW book from amazon, get a $10 used one, any vintage that deals with the air cooled VWs.
http://www.amazon.com/How-Keep-Your-Vol ... agen+alive. It will teach you everything you really do want to know about points and coil ignitions. Unlike Snowbum, it's well written for the everyday hippy mechanic and it's fun. Pics. worth framing. Add a Clymers (beware of errors!) and maybe a Haynes just to waste the money and you are set.
The VW book with do for an intro to carbs but those were downdraft Solexes. You really want the Bing manual to know the Bings work. Good news is they are dead simple.
try a trouble light instead of the ohm meter. Just make one maybe---with micro clips on the wire ends. Goes under the seat nicely too.
Do not turn the engine with the alternator rotor bolt unless you remove the plugs. I avoid turning the motor with that bolt at all. Kickstarter or rear wheel work fine.
yes, you want to time dead on the S mark. But the points gap has to be pretty on or it throws you off---and the dwell won't be right. And you gotta clean them or the new ones burn on you... Read the book. You want to know WHEN the points open. Should be on S set static. if you just check that they are open on S but don't notice WHEN they open, that could be on L, M, N,or Q. No good.
There is a heavy rubber hose between the carb and the head. Any air leakage it its joints will lean out the mix. Makes it hard to start. Starting fluid helps with diagnosis. if those are hardened and cracked, replace. But you can limp them with smears of silicone sealant short term and get up and running. Then add to next parts order or make some. Big leaks will hurt starting. Little leaks not so much but it sure won't run right when you rev it and the vacuum builds.
Tight exhaust valve = very hard to start. Double check.
You want 5k ohm resistance in the spark plug secondary circuits. Resistor plugs and non-resistor cables or vice versa. Never both,. Never carbon core cables, only copper core. It will start and run with no resistance although the sparks are shorter duration.
It's an old bike. Clean every electrical connection. This will be more important sorting the starting and charging systems.
No compression = no start. What do you mean you put the funny wrinkeled ring at the top of the piston? When you get it running, check compression with it warmed up, carbs off.
I assume you have looked at the air filter. Remove it when using starter fluid.
Starters overheat. Bad. Don't crank and crank. If it don't fire after turning over 4-5 times figure Allah don't wuv you and change something or set up a diagnostic. Let that starter cool (as in the brushes and commutator that you can't just put a hand on and check temp) while you put a small charger on the battery.
I pay attention to the heads on fasteners and look for poorly patched in elec accessory circuits. Both say the PO was a hack.
Edit:
You cannot pull the upper plastic air tubes, open the throttle butterfly and just spray starter fluid in the carb. Works poorly. You have to open the throttle butterfly, then reach in with a popsical stick and lift the piston,
then spray in the carb. Once running you can spray into the partially opened butterfly. An interesting feature of the CV carb is it is a vacuum slide type. You open the butterfly with the throttle (just like a FI throttle body) but the real throttle is a vacuum operated slide (round cylinder slide). When the vacuum builds in the venturi a diaphragm above the slide raises it opening the real throttle. That slide has a tapered metering needle hanging out the bottom going into a jet (orifice). As the slide raises the needle withdraws from the jet making a bigger and bigger hole for gas. look and see with your popsicle stick but don't bend it. Some are "alloy" and fragile. This setup makes the carbs self adjusting in certain ways, and fuel efficient. But they ain't real responsive. look in your manual and set the carb to the nominal values to begin balancing them. This screw so much open, that one so much closed, throttle cables slack, etc. That will at least get you an idle. if anything open the idle air screw and extra 1/4 to give you a richer starting mix if working in the cold. The o-ring on that screw, or on the idle mix jet feeding it, can be hardened, cracked, broken. This will murder the starting mix. When warm you can get away with it although you can't balance the carbs. In the cold...problems. But this all assumes you have tested for a fuel problem with the starter fluid and confirmed you got one. Then you go after what the carbs are doing. There is a source for cheap kits that will cover the basics. (like $30 for both carbs and includes the expensive diaphragms---from a real dealer no less---avoid eBay crap at all costs)
