Mystery Hole

[Wilf]

I have 2 questions about my 1965 Super Hawk motor (CB77E-1001528):

Should I be able to rotate the points cam approximately 10 degrees cw before I feel the advance springs begin to stretch? My guess is no and that all the slack I feel is the cause of the top end clatter and my difficulty in getting the motor to settle down at idle.

Secondly, the photo shows a hole in the top right rear engine case that I am guessing is there to accommodate the fuel overflow tube from the carbs. Is this a correct guess?

Thanks in advance.

Wilf

[e3steve]

Wilf, there is some movement of the points' cam before any resistance is felt. Check the spark advance with a strobe timing light after static setup as per the Emo recipe in FAQ http://www.honda305.com/superhawk/ -- 45º-48º max [5º btdc + 43º max advance] when giving the throttle some beans; there's a max advance timing mark on the rotor. A timing light will reveal any over-advance and, thus, suspect cam sprocket rivets. Advance commences at 1100rpm and ends at 3300rpm.

Can't help with that hole, but there should be no tubes on the carbs' bowl spigots; they're float chamber breathers, not overflows. If Our Father, Who Art In Kerrville finds you have tubes on there He'll track you down and tie your shoelaces together!

[Dgormley]

Wilf, that hole is for the crankcase breather( at least that's where the one on my CL is) that comes off the top of the head.............................D

[LOUD MOUSE]

Nope. ........lm

Wilf, that hole is for the crankcase breather( at least that's where the one on my CL is) that comes off the top of the head.............................D

[Wilf]

Thanks for your replies.
This is a CB77, so the breather tube from the top of the motor goes into the hole right under the hole for the alternator and starter motor wires.

These two photos show my concerns about the advance mechanism. In the first shot the points cam is all the way retarded and you can see that the hook on the spring is not in contact with the advance arm. The second shot shows the points cam advanced so that the advance arm just meets the hook on the spring. By this point, there is a 3mm gap between the arm and the camshaft. In effect, the points cam has been able to rotate about 10 degrees before it begins to work against the spring tension. I think this is too much play and is the cause of my erratic idle.

Any comments or further suggestions on the mystery hole?

Wilf

[Wilf]

I see I uploaded the photos in the wrong order, but they are labeled correctly.

By the way e3steve, I did use a timing light after setting the points according to lm's faq. The timing at idle seems to float around quite a bit but is stable at higher rpms.

Wilf

[e3steve]

By this point, there is a 3mm gap between the arm and the camshaft. In effect, the points cam has been able to rotate about 10 degrees before it begins to work against the spring tension. I think this is too much play and is the cause of my erratic idle.

I'd tend to concur with that.

I see I uploaded the photos in the wrong order, but they are labeled correctly.

By the way e3steve, I did use a timing light after setting the points according to lm's faq. The timing at idle seems to float around quite a bit but is stable at higher rpms.

Wilf

You need to upload photos in reverse order, I discovered early in my posting history! Max of 5 per post.

Ed's watching, so I'm sure he'll comment on the state of your advancer springs; I'd say they need replacing -- assuming the rivets aren't loosened. As you appear to have it apart, that's a simple thing to check.