CB360 left point gap

MikeMcD

New Member
Can anyone tell me why my left points continue to open wider after the index mark on the advance cam. Set at .014 at the mark, when the mark is at the 6 o clock position they are now .015-.016. The right side points stay at .014 and decrease until they close. NOS points and NOS advancer. The bike is running but I cant get it dialed in timing wise
 

teazer

Over 10,000 Posts
DTT BOTM WINNER
I would guess that the cam isn't exactly symmetrical but that shouldn't matter. Rotate the motor until the points are fully open, then adjust to teh correct gap. It doesn't matter what marks are there . Just focus on maximum opening. After setting the gap on both sets of points, then adjust the points on the backing plate to get the timing right. usually/often one set of points is fixed on the backing plate so you set timing on that side first. The other set can usually rotate to adjust timing on that second set.

Particularly on early Honda twins, it was not unusual to run out of timing adjustment and at that point we had to adjust the gap to get the right opening time on the second set.

As long as the gaps are close enough, what matters more is the time they crack open and start the fire.

A better idea all round is to replace points with a DYNA or similar electronic system.
 

irk miller

You've been mostly-dead all day.
DTT BOTM WINNER
Might make more sense to adjust the timing for both sides and don't worry about the gap. Something might be worn to make the difference.
 

pidjones

Over 1,000 Posts
From a non-professional, just my experience:

On several GL1000s I have found that you need to go back-and-forth between gap and timing due to tollerances and wear. Timing is of course most important, but gap effects dwell (time the coils have to build stored energy that they release when the points open). "In the day", mechanics used a dwell meter to adjust point gap. Today the meters are hard to find and few mechanics know what they are let alone how they are used. As electronics improved in the 60's and 70's, gap became the criteria as the coils improved to permit a wide range of dwells. I seem to remember several gurus recommending setting the gap at maximum in the range, which would decrease dwell. There is usually supposed to be a mark on the points cam indicating where the high point is. Mine have been hard to find. Make sure the points cam is smooth, not rusted or gouged. And, make sure the advance springs have returned it to minimum advance.
 

irk miller

You've been mostly-dead all day.
DTT BOTM WINNER
From a non-professional, just my experience:

On several GL1000s I have found that you need to go back-and-forth between gap and timing due to tollerances and wear. Timing is of course most important, but gap effects dwell (time the coils have to build stored energy that they release when the points open). "In the day", mechanics used a dwell meter to adjust point gap. Today the meters are hard to find and few mechanics know what they are let alone how they are used. As electronics improved in the 60's and 70's, gap became the criteria as the coils improved to permit a wide range of dwells. I seem to remember several gurus recommending setting the gap at maximum in the range, which would decrease dwell. There is usually supposed to be a mark on the points cam indicating where the high point is. Mine have been hard to find. Make sure the points cam is smooth, not rusted or gouged. And, make sure the advance springs have returned it to minimum advance.
The dwell is determined by the shape of the cam lobe. That's what is timing the spark. Shrinking the gap advances the spark, so you make a second adjustment with the plate. On a CB360, the procedure is you set the points gap to 014, set the timing on the left side, then set the timing on the right side. It's unlikely that your right side will stay at 014, which is why you focus on timing.
 

MikeMcD

New Member
From a non-professional, just my experience:

On several GL1000s I have found that you need to go back-and-forth between gap and timing due to tollerances and wear. Timing is of course most important, but gap effects dwell (time the coils have to build stored energy that they release when the points open). "In the day", mechanics used a dwell meter to adjust point gap. Today the meters are hard to find and few mechanics know what they are let alone how they are used. As electronics improved in the 60's and 70's, gap became the criteria as the coils improved to permit a wide range of dwells. I seem to remember several gurus recommending setting the gap at maximum in the range, which would decrease dwell. There is usually supposed to be a mark on the points cam indicating where the high point is. Mine have been hard to find. Make sure the points cam is smooth, not rusted or gouged. And, make sure the advance springs have returned it to minimum advance.
Im old enough to have owned and used a dwell meter :)
 

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