Author Topic: Tuning-Or trying to  (Read 725 times)

0 Members and 1 Guest are viewing this topic.

Offline Phoenix

  • Hot Shot
  • ***
  • Posts: 273
  • 4 wheels move the body. 2 wheels move the soul
Tuning-Or trying to
« on: July 12, 2018, 06:38:42 PM »
Stock except 836 kit and H/M ignition.  Brand new plugs.
Adjusted dwell with a meter.  When I tried the timing light, instead of seeing the "F" as I should have, I saw the "1" in 1-4 and the "2" in 2-4 after moving the plate as far clockwise as it would go.  Points and plate are TEC.  When I went to run it, some of the time it would run up thru the gears, it worked fine.  I was hitting it hard.  Most of the time it would pop and miss out, in any gear, when less than 3000 rpm.  Like when going from stoplight to stoplight.  Does any of this make any sense.  I'm sick of pissing my summer away trying to get my steed to run.
Ed Spengeman
Indy
1971 CB750K1 (Stock)
1973 CB350 Twin  (Gone)

Offline calj737

  • Really Old Timer ...
  • *******
  • Posts: 21,040
  • I refuse...
Re: Tuning-Or trying to
« Reply #1 on: July 12, 2018, 06:47:10 PM »
Most of the time it would pop and miss out, in any gear, when less than 3000 rpm.
Are you describing an "igntion" issue or a "transmission" issue when you say "pop and miss out"? I hope you're referring to a spark event given the reference earlier to timing marks.

If you removed the igntion plate, and the points cam, it is possible you installed the point cam 180* out. There's a very faint dimple on the circumference that aligns to a spot on the ignition plate. This can cause problems aligning the timing marks.

With your 836 kit, did you use a stock camshaft or aftermarket? Did you degree in the cam? Do you have an adjustable cam sprocket, or is everything other than the overbore fully stock?

Avoid shifting the bike under 3,000 RPMs too. Thats lugging the engine and your SOHC doesn't prefer that rev range. Crank it up above 6,000 and run it nearer to 9,000. Your motor will thank you, and your grin will increase like it was fueled by Viagra
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline seanbarney41

  • not really that much younger than an
  • Really Old Timer ...
  • *******
  • Posts: 10,842
Re: Tuning-Or trying to
« Reply #2 on: July 12, 2018, 06:57:28 PM »
If you have not already, make sure your advancer works properly.   And as Cal mentioned, make sure it is assembled properly.
If it works good, it looks good...

Offline Phoenix

  • Hot Shot
  • ***
  • Posts: 273
  • 4 wheels move the body. 2 wheels move the soul
Re: Tuning-Or trying to
« Reply #3 on: July 13, 2018, 08:34:54 AM »
Thanks for the responses.  I just put the engine back together after having the head off.  This is leading me to believe I might have been 180 degrees off when I timed the cam.  I guess there is no way to check that short of taking it apart again.  I could swear I checked it before locking it up but you what thats worth.  I'll keep you posted.
Ed Spengeman
Indy
1971 CB750K1 (Stock)
1973 CB350 Twin  (Gone)

Offline calj737

  • Really Old Timer ...
  • *******
  • Posts: 21,040
  • I refuse...
Re: Tuning-Or trying to
« Reply #4 on: July 13, 2018, 08:42:13 AM »
Hold tight- The "camshaft" can't really go in 180* out. We are talking about the points cam under the right side round cover. The advancer mechanism is a cam behind the points plate. This can easily be checked by simply removing the cover, and verifying the alignment dimples while the motor sits in the frame.
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline Phoenix

  • Hot Shot
  • ***
  • Posts: 273
  • 4 wheels move the body. 2 wheels move the soul
Re: Tuning-Or trying to
« Reply #5 on: July 13, 2018, 09:43:43 AM »
Cal
Do you realize what you just saved me.  I was all set to jump back in.  I haven't touched the cam plate you are showing.  I had it off about four years ago to check the advance but not since.  I replaced the points and plate about two years ago when I went to H/M's ignition.  So based on that, how come I can't adjust the plate far enough to get to "F" when I time it.
Ed Spengeman
Indy
1971 CB750K1 (Stock)
1973 CB350 Twin  (Gone)

Offline scottly

  • Global Moderator
  • Really Old Timer ...
  • *****
  • Posts: 16,288
  • Humboldt, AZ
Re: Tuning-Or trying to
« Reply #6 on: July 13, 2018, 09:56:39 AM »
The point gap is probably too large. Reset it to .012".
If the point cam is 180* out, like flyin900's was, the motor won't run at all, Cal. ::)
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline Phoenix

  • Hot Shot
  • ***
  • Posts: 273
  • 4 wheels move the body. 2 wheels move the soul
Re: Tuning-Or trying to
« Reply #7 on: July 13, 2018, 10:34:32 AM »
What dwell would that be?
Ed Spengeman
Indy
1971 CB750K1 (Stock)
1973 CB350 Twin  (Gone)

Offline TwoTired

  • Really Old Timer ...
  • *******
  • Posts: 21,805
Re: Tuning-Or trying to
« Reply #8 on: July 13, 2018, 11:23:45 AM »
What dwell would that be?

The actual dwell is 190 degrees (point closure timing).  Most dwell meters have their own interpretation.  Most popular seems to be about 47 degrees.

This was found by carefully setting the point gap on brand new points and noting what is displayed on the dwell meter.

Cheers,
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline Phoenix

  • Hot Shot
  • ***
  • Posts: 273
  • 4 wheels move the body. 2 wheels move the soul
Re: Tuning-Or trying to
« Reply #9 on: July 13, 2018, 06:09:27 PM »
Well, I adjusted the points so I could time it at the "F" mark.  The gaps came out to 11 to 12.  Still missing out like a bandit.
Ed Spengeman
Indy
1971 CB750K1 (Stock)
1973 CB350 Twin  (Gone)

Offline scottly

  • Global Moderator
  • Really Old Timer ...
  • *****
  • Posts: 16,288
  • Humboldt, AZ
Re: Tuning-Or trying to
« Reply #10 on: July 13, 2018, 08:08:55 PM »
Now that your timing is properly set, when did the "missing" start? Define "missing"; to me, that means a cylinder sometimes doesn't fire, but does fire most of the time.
First thing I would do is remove the spark plugs and examine the tips. Pics might help with the diagnosis. ;)
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....