Author Topic: Help! Sparks in 2-3 points on letting go of the throttle  (Read 2306 times)

0 Members and 1 Guest are viewing this topic.

Offline ev0lve

  • Master
  • *****
  • Posts: 1,930
Help! Sparks in 2-3 points on letting go of the throttle
« on: April 03, 2009, 04:19:20 PM »
Just finished a tune up, cleaned up the points, gapped them, set the timing for 1-4 and 2-3 to what the book says is good (F at idle - between the two lines at advance), then took the new Carbtune and synced the carbs. It seems to be running pretty well I think and then I look down while blipping the throttle and as the motor's returning to idle I see this (illustrated below since I couldn't get a pic) also it pops a little now just off WOT (coming down). BTW, this pic is from before the tune up.



What the heck is going on there? The blue lines are where I saw sparks coming from. Also it pops a bit. Help!

fuzzybutt

  • Guest
Re: Help! Sparks in 2-3 points on letting go of the throttle
« Reply #1 on: April 03, 2009, 04:25:05 PM »
did you replace the condensers too? i know a bad one would make the points spark.

Offline ev0lve

  • Master
  • *****
  • Posts: 1,930
Re: Help! Sparks in 2-3 points on letting go of the throttle
« Reply #2 on: April 03, 2009, 04:32:51 PM »
Nope. Same points same condensers. The spark is red BTW. Friction not electric? I can't imagine what the heck it is.

fuzzybutt

  • Guest
Re: Help! Sparks in 2-3 points on letting go of the throttle
« Reply #3 on: April 03, 2009, 04:35:51 PM »
wow, i dont know then. i dont think that there could be enough fristion there to make sparks but theres always a first time for everything.

Offline mystic_1

  • Really Old Timer ...
  • *******
  • Posts: 6,071
  • 1970 CB750K
Re: Help! Sparks in 2-3 points on letting go of the throttle
« Reply #4 on: April 03, 2009, 04:39:48 PM »
Double-check your gaps, changing the timing can sometimes throw off the gap, because the slots in the plates are not a perfect fit for the screws that pass through them, and sometimes the backing plate is not a perfect for for the bosses in the case that it rides in, so sometimes you get some wiggle.

Also verify that none of the terminal ends on the wires are contacting the base plate, etc and shorting.  Did you take the points off of just clean them in place?  Make sure all the insulating washers are in the right places on the points; screw posts.

The popping coming down from WOT seems like it may be more of a carb thing.  What adjustments did you need to make while syncing?

mystic_1
"A ship in harbor is safe, but that is not what ships are built for."
- John Augustus Shedd

My build thread:  http://forums.sohc4.net/index.php?topic=68952.0

Offline ev0lve

  • Master
  • *****
  • Posts: 1,930
Re: Help! Sparks in 2-3 points on letting go of the throttle
« Reply #5 on: April 03, 2009, 04:43:12 PM »
Yeah, thinking about that it's in between the arms where the spring is. No real friction there and if there was it would increase as the RPMs went up I suppose.

So red spark on deceleration? WTH? Condenser?

Offline ev0lve

  • Master
  • *****
  • Posts: 1,930
Re: Help! Sparks in 2-3 points on letting go of the throttle
« Reply #6 on: April 03, 2009, 04:52:00 PM »
Double-check your gaps, changing the timing can sometimes throw off the gap, because the slots in the plates are not a perfect fit for the screws that pass through them, and sometimes the backing plate is not a perfect for for the bosses in the case that it rides in, so sometimes you get some wiggle.

Can do!

Quote
Also verify that none of the terminal ends on the wires are contacting the base plate, etc and shorting.  Did you take the points off of just clean them in place?  Make sure all the insulating washers are in the right places on the points; screw posts.

Yep, took the whole thing apart, greased the points cam, cleaned up the points. Had to think about where the insulating washers went. Seems a likely failure. I'll check.

Quote
The popping coming down from WOT seems like it may be more of a carb thing.  What adjustments did you need to make while syncing?

mystic_1

Hmm, I took some pics but posting this from a dial up so... no pics very quickly,

1 through 4 with the carbtune on it
-----------
----
-----
-------

fiddled with it till I got

-----
-----
-----
-----

They flutter a little still. Not solid at idle. I don't know that's not normal though.

Thanks!




Offline ev0lve

  • Master
  • *****
  • Posts: 1,930
Re: Help! Sparks in 2-3 points on letting go of the throttle
« Reply #7 on: April 03, 2009, 05:29:54 PM »
Being a noob is starting to hurt my feelings a bit.

bolt - washer - condenser connection - washer - insulator

Changed to

bolt - washer - washer - condenser connection - insulator

No red spark. Basics. Always the frickin basics. There's a reason mechanics get paid  ::)

Many thanks for the replies!

Offline mystic_1

  • Really Old Timer ...
  • *******
  • Posts: 6,071
  • 1970 CB750K
Re: Help! Sparks in 2-3 points on letting go of the throttle
« Reply #8 on: April 03, 2009, 05:34:00 PM »
Excellent.

If I might suggest, post pics of your final arrangement as a reference for others who may run into the same problem.

cheers!

mystic_1
"A ship in harbor is safe, but that is not what ships are built for."
- John Augustus Shedd

My build thread:  http://forums.sohc4.net/index.php?topic=68952.0

Offline ev0lve

  • Master
  • *****
  • Posts: 1,930
Re: Help! Sparks in 2-3 points on letting go of the throttle
« Reply #9 on: April 03, 2009, 05:47:34 PM »
Mo definetely! I like to console myself with the thought that documenting every stupid thing I do might help someone... someday ;D

Edit:
I didn't grab an after pic so here's the before pic I referenced against what I did as big as I could make it and still have it upload. Hope it's helpful to someone!
« Last Edit: April 04, 2009, 07:26:47 PM by Iggy »