Author Topic: timing with gun  (Read 4392 times)

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Offline c(b)hris

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timing with gun
« on: June 05, 2011, 05:41:51 PM »
'75 CB550K

I've never set the timing with a timing gun with the engine running before.  When I pull the trigger on the gun, each time the strobe goes off it shows the plate markers in a different spot.  Is this normal?  I would expect the markers to be in the same spot until I move the plate.

Thanks a lot.
75 CB550
74 CB750

Offline Nortstudio

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Re: timing with gun
« Reply #1 on: June 05, 2011, 05:48:22 PM »
I'm pretty sure that you should be seeing it at the same spot.  Is the plate loose when you are first looking?  The vibration could be moving it around if it's loose.
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Offline c(b)hris

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Re: timing with gun
« Reply #2 on: June 05, 2011, 06:07:17 PM »
Not loose...this is before I loosened the adjusting screws, and they were super tight when I did loosen them.
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74 CB750

Offline DJ_AX

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Re: timing with gun
« Reply #3 on: June 05, 2011, 06:11:09 PM »
I've got similar issues...
but I think it's just that my points are crappy.

Have you cleaned your points thoroughly?
~ Vincent . . . '75 CB750 K5 . . . '97 BMW r1100rt . . . had; '75 CB550 K1 (sold) . . .  '73 CB350G (gifted) HELL YEAH!
Disclaimer: I could be wrong. :)

Offline BobbyR

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Re: timing with gun
« Reply #4 on: June 05, 2011, 06:12:56 PM »
It sounds like you are having a misfire.
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Offline c(b)hris

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Re: timing with gun
« Reply #5 on: June 05, 2011, 06:17:06 PM »
I cleaned my points with contact cleaner and a business card.  It looks like the points for 2-3 are having a huge spark but I don't see the spark happening for 1-4.  Ill try cleaning them again.
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Offline 2wheels

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Re: timing with gun
« Reply #6 on: June 05, 2011, 07:13:57 PM »
Try it a different RPM's.   Holding the RPM steady.
1970 CB750 K0 (I can't believe I tossed my duck tail seat in the trash 30 years ago)

Offline donpark1086

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Re: timing with gun
« Reply #7 on: June 05, 2011, 07:25:05 PM »
My gun freezes the marks and you can easily see the centrifugal advance allow the mark to "flow" back and forth as you rev to and from idle.  Maybe a bad gun.

Offline Deltarider

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Re: timing with gun
« Reply #8 on: June 05, 2011, 10:55:14 PM »
A mechanic once taught me to use an external battery to power the strobe gun to avoid interference. Maybe this can help you. Could be your contact breakers are not mounted properly and misaligned. Check and doublecheck. Did you have the advancer unit apart?
« Last Edit: June 05, 2011, 10:59:25 PM by Deltarider »
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Offline c(b)hris

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Re: timing with gun
« Reply #9 on: June 05, 2011, 11:09:26 PM »
A mechanic once taught me to use an external battery to power the strobe gun to avoid interference. Maybe this can help you. Could be your contact breakers are not mounted properly and misaligned. Check and doublecheck. Did you have the advancer unit apart?

I'll give the external battery a try.  I think it must be worn out points though.  They look badly corroded.  When I clean the points the bike runs really well for a minute and the gun flashes predictably.  After a few minutes, the flash from the gun is erratic.  I'm going to try replacing my points I think.  How often does everyone else replace points?

thx
75 CB550
74 CB750

Offline Deltarider

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Re: timing with gun
« Reply #10 on: June 05, 2011, 11:13:36 PM »
Mine have done over 55000 kms, but... that's with a transistor ignition module (similar to Hondaman's).
Original Honda points live longer than counterfeit.
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Offline c(b)hris

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Re: timing with gun
« Reply #11 on: June 06, 2011, 06:51:50 AM »
A huge spark at the points may indicate a bad capacitor. It's there to reduce the arcing and prevent the points burning out.Try strobing 2 and 3 to check the tool.
I'll try 2/3 tonight.  I tested the condensers with my voltmeter per someone else's thread, with one lead on the green wire and the other on the mounting screw measuring resistance.  After a couple seconds it stabilized and stayed at 0.  Would that indicate a good condenser?
75 CB550
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Offline jimbir

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Re: timing with gun
« Reply #12 on: June 06, 2011, 08:13:49 AM »
Sparking at the points indicates a bad condenser. When you test the condenser, be sure the points are open.0 Ω is a good reading, anything more indicates a short which is no good. Sparking at the points will drive your strobe crazy.
1976 Honda CB550F

Offline c(b)hris

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Re: timing with gun
« Reply #13 on: June 06, 2011, 08:55:13 AM »
Sparking at the points indicates a bad condenser. When you test the condenser, be sure the points are open.0 Ω is a good reading, anything more indicates a short which is no good. Sparking at the points will drive your strobe crazy.

When I tested the condensers I disconnected the green wire altogether.  In that case would it still make a difference if the points were open or closed?  I'll test again and pay attention to that.  thx. 

Ordered replacement points today.
75 CB550
74 CB750

Offline jimbir

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Re: timing with gun
« Reply #14 on: June 06, 2011, 09:13:40 AM »
If the green wire was disconnected, then the reading should be accurate. Try trading the condensers between point sets and see if the sparking follows the condenser.

Jim
1976 Honda CB550F

Offline Bodi

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Re: timing with gun
« Reply #15 on: June 06, 2011, 09:18:54 AM »
Bad sparking can be from dirty contacts (it's common for some grit to get stuck in there if you clean them with emery or crocus cloth) but usually indicates a bad capacitor. Capacitors are difficult to test accurately - some digital multimeters have a test function but that usually only works for very low value caps. I would get new ones. They are not expensive. Swapping them and seeing if the sparking follows the caps is a good idea.

Offline c(b)hris

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Re: timing with gun
« Reply #16 on: June 06, 2011, 09:36:03 AM »
If the green wire was disconnected, then the reading should be accurate. Try trading the condensers between point sets and see if the sparking follows the condenser.

Jim
Bad sparking can be from dirty contacts (it's common for some grit to get stuck in there if you clean them with emery or crocus cloth) but usually indicates a bad capacitor. Capacitors are difficult to test accurately - some digital multimeters have a test function but that usually only works for very low value caps. I would get new ones. They are not expensive. Swapping them and seeing if the sparking follows the caps is a good idea.

something fun to do while I wait for my points in the mail.  i'll give this a try tonight too.  thanks everybody for the information.
75 CB550
74 CB750

Offline jimbir

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Re: timing with gun
« Reply #17 on: June 06, 2011, 09:57:06 AM »
Where'd you buy your points? Send link please. How much? Are they genuine Honda? Beware of cheap imitations you'll never get them timed right. The PO put some on my bike and I can't move the plate for plugs 2 and 3 far enough to time them.

Jim
1976 Honda CB550F

Offline c(b)hris

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Re: timing with gun
« Reply #18 on: June 06, 2011, 11:05:08 AM »
Where'd you buy your points? Send link please. How much? Are they genuine Honda? Beware of cheap imitations you'll never get them timed right. The PO put some on my bike and I can't move the plate for plugs 2 and 3 far enough to time them.

Jim

I had the local dealer order them in.  They said they didn't know the brand, but Im hoping they're not the infamous daiichi type.  The said the part number was superseded and the old one was hitachi, but they weren't sure about this one's brand.  Their prices are always about $5 more than bikebandit and I think they use the same part numbers as the oem map on the bikebandit site.  I ordered something over the phone from the dealer once and I told them the number on the diagram I was looking at on bikebandit and it coincided with what they were looking at.  Maybe that just means the diagram is from Honda, idk...but they'll be here Thursday or Friday and that's quicker than bikebandit.

If they're daiichi im returning them and looking somewhere else.  They were about $25 each so that makes me think they're not the cheapies. 

http://www.bikebandit.com/houseofmotorcycles/1975-honda-cb550k1/o/m9232#sch401317
#20 and #21.

These guys have the set of points and condensers for $35 but they're daiichi.
http://www.siriusconinc.com/pro-detail.php?pid=&product_id=1474

75 CB550
74 CB750

Offline c(b)hris

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Re: timing with gun
« Reply #19 on: June 09, 2011, 07:54:39 PM »
Points came today.  TEC brand. 
Here's some more info for the ones I ordered:


old points:


new points   :D


word to your mother.

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Offline DJ_AX

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Re: timing with gun
« Reply #20 on: June 09, 2011, 08:51:31 PM »
New points put in today worked for me!
What a world of difference.
Hope it does the trick for ya.
~ Vincent . . . '75 CB750 K5 . . . '97 BMW r1100rt . . . had; '75 CB550 K1 (sold) . . .  '73 CB350G (gifted) HELL YEAH!
Disclaimer: I could be wrong. :)

Offline grcamna2

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Re: timing with gun
« Reply #21 on: June 09, 2011, 09:21:34 PM »
    I sure do miss the flexible special points files of yesteryear; you know
the "flex stone" type ? ! I know that they are the Best.
 I used to get some from the Flanders co. in the late 90's...but now even
 they can't get them. What I enjoyed about them is they are "flexible"
and don't change the original angle of the mating surfaces of the
contacts.The solid steel files (all that seems to be avail. now) are not
accurate and tend to mess up the points more than dress the original
surface of the contacts. I hate em. The "Flex stone" points files are
excellent; you can use a small area until all the grit is worn off & then just
break off that end and you have a fresh new points file every time !

     Does  ANYBODY  know where I can purchase a FRESH pack of them ? !
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
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Offline Retro Rocket

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Re: timing with gun
« Reply #22 on: June 09, 2011, 11:30:14 PM »
Love the title Chris, makes it look like that you got fed up with trying to tune it and just shot it..... :o ;D
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Offline dave500

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Re: timing with gun
« Reply #23 on: June 10, 2011, 12:36:15 AM »
replace all the tiny screws while your at it,improves accuracy if your not slipping and fumbling with worn out screw heads.

Offline MoMo

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Re: timing with gun
« Reply #24 on: June 10, 2011, 04:56:59 AM »
    I sure do miss the flexible special points files of yesteryear; you know
the "flex stone" type ? ! I know that they are the Best.
 I used to get some from the Flanders co. in the late 90's...but now even
 they can't get them. What I enjoyed about them is they are "flexible"
and don't change the original angle of the mating surfaces of the
contacts.The solid steel files (all that seems to be avail. now) are not
accurate and tend to mess up the points more than dress the original
surface of the contacts. I hate em. The "Flex stone" points files are
excellent; you can use a small area until all the grit is worn off & then just
break off that end and you have a fresh new points file every time !

     Does  ANYBODY  know where I can purchase a FRESH pack of them ? !


Probably the Snap On man.  FWIW, the beauty section in a department store will have crocus nail files that are a good substitute...Larry