TOPIC:

Hi folks.
I'm wondering if anyone can recommend a quality mechanic/technician in the Waco, Texas area?
At the end of my rope getting my '79 650-C3 to start or run and need someone with experience to diagnose it.

What is it doing?
Steve

I don't know about the Waco area, but if you want to come to Houston, Cycle Sports, Ltd at 9802 Clay Road can fix you up. I've been a customer of theirs since the late 20th century!

So far the thing behaves totally as expected but just can't seem to catch and run. There have been problems along the way of course that has taken 3 weeks since my 1st attempt. New battery was bad. One of the new coils was bad. I had the BR plugs initially. The carb rebuild turned out to be a sheared idle jet & i needed to replace carb #3. I rebuilt the whole rack (stripped down to every removable part) and replaced all jets & rubber & bowl gaskets etc. I realized recently my main jets are 90 (that's what came out so those were what i replaced with) & manual states 102.5 should be but i haven't gotten to running so these shouldn't matter yet; right? Rack was static synched using a 14awg wire. Air mix at 2 turns out.
Bottom line observations:
Points are sparking & gapped at .004mm. Plugs arc (after swapping out new coil with one from my kz1000). Gas on bottle feed goes in. 2 carb ports vent to atmosphere & 1 port is plugged (for petcock vacuum).
I can roll on starter until main battery leads get hot & engine randomly stumbles but not yet run for even 10 seconds.
I've been chasing this for so long now i'm starting to think about the definition of insanity - doing the same things over & expecting different results. Ugh.

The points should not be sparking. Bad condensers. I had that problem and picked up two early Ford ones and wired them in under the tank and disconnected the old ones. Have you tried starting fluid?
Steve.

Hey Steve!
Thanks again man. I appreciate the insight and help.
Guess, it's more about frustration at this point. Obviously, I'm missing something and I find it rather ironic that almost every part of the ignition system that I've replaced with new parts has turned out to be another piece of the problem.
So my new condensers are bad too? :: Roll eyes emoji :: No good deed goes unpunished right?
My new battery (the 2nd one) turns out to be 1/4" too large to fit into the battery tray, so I'm needing a 3rd new battery now AND another pair of condensers...

I actually did buy a can of starting fluid and even attempted to use it once but found it super difficult to actually spray it into the carbs with the air box mounted. You pretty much have to turn the can upside down to spray at the carb intakes and then the can just barely fits through the hole for the air filter (removed air filter of course). The end result, which was before I took the carbs back out and discovered the sheared idle jet, was it seemed to make no difference in the sound or performance of the engine. BUT, I also doubted that I got much if any of the ether to actually go into the carb throttle bodies due to the difficulties in aiming the inverted can blindly at 4 ports inside the air box.

It's getting to the point that I may just shelve the whole thing until the autumn when it's not so unbearable to be working in the garage due to heat, which is part of my frustration - sweating profusely in 100 degrees makes me tend toward the "F it!" mode of problem solving. You may know what I mean given that you too live with 100+ temps too?

The whole thing is making me doubt pretty much everything I've done at this point. I may just have to remove the valve cover and quadruple check that I actually got my cams timed correctly too.

This is why I wanted to just take it to a shop that is knowledgeable with these old bikes because they'd recognize problematic condenser or quasi coil or carb issues that I am simply unfamiliar with AND they're likely to have the parts handy to swap out and confirm. I mean, I never tested the original condensers, just replaced them on principle. Ditto for the coils; both of which it seems now were DOA parts. Go figure.

I know about the heat. Was just throwing ideas out there. I've tested condensers as suggested in the manual and never had one spark in 40+ years. I was only suggesting if the points are sparking a lot, that's your problem. A small amount won't keep it from running just not very well. I've hooked my coils up backwards countless times only to switch the power leads and have it fire up. It's usually something stupid. I'd try running a hot wire directly to the power lead to the coils to rule out a bad switch or something. One tooth off on the cam chain it will want to start. From the advice you've given others I doubt it could be any farther off than that.
Spraying starting fluid in the air box should get it to fire if it's going to. Just stand back when you do. My highest energy times are in the morning. After a while I can't see the "forest for the trees." I'll look straight at something and not see it. Take your time and walk away if it's getting to you. Come back fresh and you'll find it.
Steve

wrenchmonkey wrote: ..........................Points are sparking & gapped at .004mm..

Why .004mm? The correct points gap is 0.35mm. I suggest you reset the points and ignition timing; here's how I do the static timing:

The manual has several pages of instructions, pictures, etc. on how to set the timing using the static method plus timing light, plus dwell meter. I can give you a fairly easy way that will get you in a pretty close ballpark without a timing light or dwell meter, but you will need a 0.35 mm feeler gauge and an ANALOG multi-meter or other device to test continuity. To be very precise, the timing light and dwell meter will be needed.

Before attempting to replace or adjust the points the following is important to understand; timing is comprised of two separate components, and BOTH of these components MUST be set properly if the engine is to run well:

--- The GAP – this is the distance the points spread apart when fully open. This is set by adjusting the points. The GAP is the element that determines the DWELL. In essence, the DWELL is the number of degrees of points cam rotation that the points are closed and this controls the amount of time the coils receive a charge before firing the spark plugs.

--- The TIMING of the initial opening of the points (the point at which the continuity across the points breaks) controls the precise instant that the coils receive the signal to fire the spark plugs. This is set by turning the backplate AFTER the gap is set.

Remove the points cover on the right side of engine. Under it you will see 2 sets of points. The set on the left fires cylinders 1 & 4; the set on the right fires 2 & 3. When replacing points observe carefully how the little bits and pieces are arranged where the wires attach. Some of those pieces are actually insulators and if you leave any of them out or put them back in the wrong place the points will be grounded and won't work. Take a very close look at the contact surfaces of the points. If they are pitted you really should replace them. You can sand down pitted points, but they will quickly pit again. Replace one set of points at a time so you can look at the other set in case you get the little bits confused.

When adjusting the points, use a 17 mm wrench to turn the nut NEAR the end of the crankshaft clockwise while looking in the hole above that nut. (Do NOT use a wrench on the smaller bolt on the very end of the crankshaft to turn the engine.) Inside that hole you will see a vertical pointer cast into the casing. As you turn the 17 mm nut you will see a 1 & 4 and F and T roll by and then you'll see a 2 & 3 and F and T roll by. Each F and T has a line next to it.

Here's the method I use for static timing. I turn OFF the ignition. I disconnect the green wire near one coil and the black wire near the other coil. (This is not in the book, but it makes checking continuity much easier for me.) After installing the new points or cleaning up the old ones, turn the 17 mm nut while watching the points. When points set 1&4 are at their widest gap adjust them (by loosening the 2 screws that hold the points to the backplate) so the gap equals 0.35 mm. Turn the 17 mm nut clockwise through a full revolution again and double check this gap. Then repeat this for points set 2&3. Now set your meter to test continuity and clip one wire to the leaf spring on points set 1&4 and clip the other wire to ground. Turn the 17 mm nut clockwise until the 1&4 "F" mark aligns with the pointer mentioned above. You want the continuity across point set 1&4 to just break when the F mark aligns with the pointer. The idea is that when the continuity just fails is when the points will fire their respective coil and cylinders. In order to adjust the point at which continuity fails you loosen the 3 screws that hold the backplate to the engine and slightly turn the backplate until the meter shows a break in continuity. Once you have the 1&4 set timed properly you can check the 2&3 set to make sure they break when the 2&3 F mark aligns with the pointer (they should or something is not right). Don't forget to plug in the green and black coil wires when you are done, and put a little grease on the rubbing block felt. Assuming you are using new points of the correct type this should enable you to get the timing very close. Trying this with old points may give poor results, especially if the points are pitted and/or the rubbing blocks are worn.

After you have set the gap (which in effect sets the dwell) and the timing using the method above you can use a dwell meter and timing light to fine tune dwell and timing. If you have followed the above procedure carefully, very little if any fine tuning will be needed.
Sorry this is so long. It's not as difficult as it sounds. Ed

There have been cases where the springs were rubbing on the plate or so far out of line, the points couldn't work right.
Steve

Ed has a out the easiest way to set points that I've seen, would reset the ignition, then double check it.

Whenever I buy a non-running bike the order of work usually goes;
1) valve clearances
2) electrical (clean all contacts)
3) carb cleaning
4) oil change
5) vroom
Any of the first three will keep the bike from running

If you ain't got it fix'd you could bring it to me.

My phone's broke so pm me here.

I would check compression