650 SS Battery.

No. A magneto has nothing to do with the rest of the electrical system. Size of battery only affects how long you can stay on the pub with lights on with stopped engine.

Not sure if this applies to later 650's like yours, but........ I have a 1962 650ss, (6 volt, magneto, monobloc carbs) that I used to have a hard time starting. Turns out that the steep inlet angle makes these models rather prone to flooding. Whereas with most brit bikes tickling is essential for cold starting, my 650ss "usually" starts easily within one or two kicks with no tickling. If I do tickle it, never more than a couple of seconds, or she floods.....

hillbone said:

hi.
I have a 1966/67 650SS. Just bought it. Magneto, very tiny 12 volt battery fitted.
Its really hard to start, runs reasonable when going.
Question: Does the battery have any impact on starting? I imagine it doesn't as I have spark at the plugs when kicking.
Just wondering and hoping I'm missing something that will help it start easier. My Atlas is so much easier .
cheers Hillbone.

PS Gidday Tex.

Click to expand...

+1 with Mike40M.
Having spark at the plugs when the plugs are pulled and electrodes shorted to ground (earth), does not verify you have spark in the cylinders under compression load. The higher the compression, the more spark energy is required to spark the plugs. A tester like that below gives a reasonably good indication of spark quality under compression load.




The physics of a magneto generates a greater spark energy with higher rpm; conversely, the spark energy of a magneto is less at kick-over rpm. To help overcome the physics of high compression requiring greater spark energy vs the physics of the magneto yielding less spark energy at kick-over rpm, modify your kick starting technique as follows:

With the kick start lever, slowly rotate the engine until you estimate the engine is midway up the compression stroke. Then pause 5 to 10 seconds to allow compression to leak off thru the ring gaps. Next, reset the kick start lever and give it your best kick. If you practice this with one of the above testers in-line with a spark plug, you will see the difference in spark quality vs the technique of rotating past TDC, then giving it a hard kick.

Inspect the slip ring of your magneto by removing one of the high tension brush holders. Check for oil or excessive carbon residue from worn brushes. if in doubt, remove the other brush holder as well.

I have had a K2FC magneto lose its magnetic strength. There is no easy way to test for this, but if it happens, hard starting is the result, but will run fine.

Good luck with this issue. Report back.

Slick

Thanksto everybody. Great advise.... Will follow.

hillbone said:

hi.
I have a 1966/67 650SS. Just bought it. Magneto, very tiny 12 volt battery fitted.
Its really hard to start, runs reasonable when going.
Question: Does the battery have any impact on starting? I imagine it doesn't as I have spark at the plugs when kicking.
Just wondering and hoping I'm missing something that will help it start easier. My Atlas is so much easier .
cheers Hillbone.

PS Gidday Tex.

Click to expand...

Magneto rectifer may be on the blink, preventing a big fat juicy spark. Miniature bolt on ones are available that can be fitted by owner.
But check if any oil in mag first as those mag oil seals were a common problem on my bike.

Bernhard said:

Magneto rectifer may be on the blink, preventing a big fat juicy spark. Miniature bolt on ones are available that can be fitted by owner.
But check if any oil in mag first as those mag oil seals were a common problem on my bike.

Click to expand...

I think you mean the condenser (also known as capacitor) located inside the magneto, not the rectifier. The rectifier converts AC to DC and, along with the Zener diode, is part of the charging system. On a magneto bike the rectifier has nothing to do with ignition. On an original bike it is usually located under the tool tray.