1967 350 BS GTR charging problems????

[Harry]

Hi Guys,  I'm getting my 67 back on the road.  It's not a show bike which is okay for me.  I have a problem getting the bike to stay running after about 20 minutes on the road.  The right cylinder fails to fire and about 2 minutes later the left one stops firing.  The battery is then almost dead and the bike  won't start up again until it's charged.  Then it will run for another 20 min. and the same thing happens.  I do have a shop manuel for the bike as well as the parts book.  What should I look for.  Charging wire not attached? Poor magneto?  Bad battery?  I'm at a loss.  Looking for any suggestions.  Harry from Pennsylvania, USA

[OldSwartout]

A  few quick basics:

A battery that will only run the bike 20 minutes is either bad or you have a pretty bad short in the system. Charge the battery, it should show 12.3+ volts, normally 12.5 - 12.7V.  The first thing to check when you have it running is the charging voltage. It should be around 13.5V with the bike revved to about 4000 rpm (lights off). Then try it with the lights on. The voltage with the lights on should be similar as there is additional charging circuit connected when you turn the lights on.  If the voltage is low in either situation, you have a charging problem, which can be a number of things, starting with connections to the rectifier and ignition switch connections. If they are clean and tight, check the rectifier. Do a search on this site, there are instructions.

If you get this far and don't find anything, ask some more questions; I or someone else can come up with other suggestions.

[dcr]

Where in PA are you?

[Harry]

dcr,  I'm In NE PA just north and west of Scranton.  Where are you?  Harry

[Harry]

Karl,  Thanks for getting back to me so quickly.  I'll try your suggestions tomorrow and let you know.  The right cylinder is not firing hardly at all now.  I'll fully charge the new battery and then let you know.  Thanks again.  Harry

[slawsonb]

I think Karl made this point, but I want to emphasize, it is critical that all the wires are connected correctly and that you have continuity on all the connections. Bad wires and loose connections are hard to diagnose and will definitely cause charging problems. Take your time and test all the connections. Your multimeter is your friend.
...bert

[dcr]

dcr,  I'm In NE PA just north and west of Scranton.  Where are you?  Harry

SE PA just outside of Philadelphia.

[Harry]

dcr, In Bucks County or Montgomery County?  We have friends in Bucks and lived there for 15 years so we know the area.  Let me know.  Harry

[Harry]

Thanks, Bert for your reply.  I'm charging the new battery not and will check points gap as well as plug gap and other suggestions.  I'll get back to all of you with the results.  Here's hoping.  Harry

[slawsonb]

You bet! Hope you have success.
...bert

[OldSwartout]

The firing problem as you originally posted (right cylinder stops firing, followed shortly by left cylinder stopping firing, then wait 20 minutes and it starts again) is also a symptom of a plugged gas tank vent (gas cap) or slow flow through the petcock. The low battery could be a separate problem. -Just something else to check if you get stymied.

[ziggy stardust]

My money is on a dud battery.

Z

[Colin]

Yup a dead cell in the battery would do it, nice call z

[Harry]

Thanks guys for all your suggestions.  I just finished pulling the seat and tank and checked all of the electrical connections as well as the connections at the rectifier.  Now I don't have any spark at all!!   I do have a problem in that the key for the main switch is stuck in the hole.  Can't get it out and it broke off.  Tried a dental pick but no luck.  Could I have shorted something in there by mistake?  Do any of you have a new or better yet used main switch assembly and key that you would sell me?   Please let me know.  Thanks, Harry

[Harry]

Thanks to all of you for your help.  Mike sent me a used master switch and key.  I think that that as well as checking all the electrical connections for the 10th time solved the charging problems and right cylinder not firing.  Got the bike started, checked both cylinders, and took it on a fairly long ride with no problems.  The battery was charging and the right cylinder didn't fail.  The bike kept going like I remember it did back in the late 70's the last time I rode it for any distance.  Today it was great to get on her again for a great ride.  Thanks to all of you on the forum for all your help.  Sincerely, Harry

[old smokey]

I didn't offer any help, but that has to be a good feeling!

[dcr]

dcr, In Bucks County or Montgomery County?  We have friends in Bucks and lived there for 15 years so we know the area.  Let me know.  Harry

Im in Chester County. Live just outside of Coatesville.