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1972 gt380 points gap anyone???

Posted: Tue Apr 30, 2013 9:29 pm
by zk0ot
i found that 76 is .14 anyone know if 72 differs?

Re: 1972 gt380 points gap anyone???

Posted: Wed May 01, 2013 2:40 am
by jabcb
Don't know if you are aware of the plastic gear issue.
Don't use the nut on the points cam to rotate the crank. The owner's manual is wrong on this.
See service bulletin 119: http://www.ozebook.com/compendium/techb ... 0mc119.pdf

Shop manual is here: http://www.oldjapanesebikes.com/mraxl_G ... index.html

Re: 1972 gt380 points gap anyone???

Posted: Wed May 01, 2013 6:59 am
by Coyote
.012 - .016

Re: 1972 gt380 points gap anyone???

Posted: Wed May 01, 2013 8:42 am
by zk0ot
jabcb wrote:Don't know if you are aware of the plastic gear issue.
Don't use the nut on the points cam to rotate the crank. The owner's manual is wrong on this.
See service bulletin 119: http://www.ozebook.com/compendium/techb ... 0mc119.pdf

Shop manual is here: http://www.oldjapanesebikes.com/mraxl_G ... index.html
havent gone that far yet. also that manual isnt very forward with that spec. i have this manual.didnt notice it anywhere.

Re: 1972 gt380 points gap anyone???

Posted: Wed May 01, 2013 8:43 pm
by zk0ot
Put the multimeter to the points. This is what I got. Battery was a little low from leaving the bike on access for a bit earlier.oops.
Left. Open 10.05v closed. 11.02v
Center. Open .15v. Closed. .14v
Right. Open 10.87v. Closed. .20v


Right seems to be the one working properly. Nothing looks burnt. I've got condensors coming. And have rotated the current ones around no change.

This thing was running fine month ago.

Re: 1972 gt380 points gap anyone???

Posted: Wed May 01, 2013 9:10 pm
by jabcb
Check the order of the parts where you attach the condenser & power to the points.
You may have it wrong for the left & center points, so compare them to the right points.

This pic might help. Your bike is a little different because you have two wires going to the points.
viewtopic.php?f=2&t=5785&start=8

Re: 1972 gt380 points gap anyone???

Posted: Thu May 02, 2013 11:56 am
by zk0ot
the lasted time i rode it. the left side seemed a little odd... but couldnt make a definite conclusion.
the next time i could here the left popping intermitantly

when the issue first arose... nothing in the points changed... havent even opened it up...
then coils.... still no spark.
then check and double check connections. none
then cleaned points with some fine sand paper and cleaner... none
then rotated condensors. none... but i didnt think to put the connectors in any certain order.
re gapped to .14mm... nothing...

Re: 1972 gt380 points gap anyone???

Posted: Thu May 02, 2013 7:01 pm
by jabcb
Your initial problem may have been dirty left points. You cleaned the points so that might be ok.

But then incorrect reassembly could cause no voltage change when the points open or close.
Also could isolate the condenser so that you get no spark when you have correct voltage change.

Your initial problem might also be associated with the condenser or coil.

Had a long day at work so I'm a bit too tired for much more info.
Could you post closeup pics of how you connected the points?

Re: 1972 gt380 points gap anyone???

Posted: Thu May 02, 2013 7:43 pm
by zk0ot
Yah. Could have been.
The coils were replaced because I ruined them trying to replace that leads.
I'll post a picture of the con sensor wires shortly

Re: 1972 gt380 points gap anyone???

Posted: Thu May 02, 2013 8:14 pm
by zk0ot
Image
Not sure if it will be large enough. The bottom left is Left. Top is Right . bottom right is Center. For the left wires are wrong

Re: 1972 gt380 points gap anyone???

Posted: Fri May 03, 2013 2:39 am
by jabcb
You've been doing some fiddling, so what are the open/closed voltages now?
Which cylinders do you now get a spark at?

For points with bad results, disconnect the condensers & check open/closed voltages.
You won't get a spark but this will help track down the problem.

Re: 1972 gt380 points gap anyone???

Posted: Fri May 03, 2013 7:48 am
by zk0ot
ill have 3 replacement condensors from the shop tonight. i will re connect them properly and see what is happening.

Re: 1972 gt380 points gap anyone???

Posted: Tue May 07, 2013 9:25 am
by Coyote
The best check is with the ignition OFF. Set your meter to check continuity. Connect the black lead to ground and the red lead to a closed set of points. You should have full continuity. Now open the points you are checking and insert a match book cover or a tooth pick between the points to hold them open. Check again. Your meter should show zero continuity. If you still have residual continuity or full continuity, something is definitely shorted.

Re: 1972 gt380 points gap anyone???

Posted: Thu May 09, 2013 7:19 pm
by zk0ot
Points came in. Plenty of spark from them all. But inconsistent ignition from the left chamber (my problem cylinder). With the choke on nothing but some gas from the exhaust gasket .. With the choke off it started popping off. But sporatically (maybe 4 stroking) . Thinking carb issue now.

Re: 1972 gt380 points gap anyone???

Posted: Thu May 09, 2013 7:42 pm
by jabcb
Maybe you should check to make sure your petcock isn't leaking.

Not an expert, but if the petcock is ok maybe you just need to go for a good ride to clear out the left cylinder.