76 Honda CB 360- refuses to spark

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vanend · #1 Unread post by **vanend** » Tue Apr 10, 2007 8:51 am

I have a '76 Honda CB360 that quit running about 2 years ago, its been passed around the family (all non-mechanics) trying to get it going again. Here's what happend: Driving on blue Ridge Pkwy my nephew rode through a puddle, the bike quit and hasn't started since. It ran great (considering it's years and miles) prior to the puddle. Everything seems to work fine except the plugs don't spark. new plugs have been installed, the coils have been checked by a bike shop, the regulator and rectifiers have been replaced, even replaced the kill switch and all fuses. I have gone through all wiring and connections for shorts, could not find any. When I put a meter on the points (with ignition and stop switch in "on" position) it reads 12.5V when I hit the starter button it the volts drop to around 10. What am I failing to do, any suggestions will be appreciated, I really want to be the one that gets this thing running agian. thanks, any suggestions will be appreciated.

flynrider · #2 Unread post by **flynrider** » Tue Apr 10, 2007 9:41 am

Have you put a meter on the primary wire going to the coils? The coils can check out fine, but if you're not supplying voltage to the primary side, you'll get no spark out the other side.

vanend · #3 Unread post by **vanend** » Tue Apr 10, 2007 9:57 am

yes, getting about 12.5v into and out of coil, right down to the spark plug. However not getting any spark at all, not even tiny one, ever.

#4 Unread post by **Sev** » Tue Apr 10, 2007 1:48 pm

You should be getting a lot more then 12.5v at the sparkplug. It's possible that the insulation has worn away and the primary windings are directly contacting the secondary windings.

flynrider · #5 Unread post by **flynrider** » Tue Apr 10, 2007 2:59 pm

I agree. The purpose of the coil is to convert 12v to thousands of volts. If you're still getting 12v toward the spark plug, you've got a coil problem. 12v is nowhere near enough to jump the spark plug gap.

Johnj · #6 Unread post by **Johnj** » Tue Apr 10, 2007 5:39 pm

Take a resistance reading from the coils battery connection to the coils points connection with all the wires pulled off. (I hope your using a digital meter) You should only have a couple of ohms. Now move one of the leads to the spark plug connection, it doesn't matter which one. The meter should show an open.

revcbl · #7 Unread post by **revcbl** » Mon Apr 16, 2007 2:51 pm

Just a thought, and you may have this sorted out by now, but this bike has one coil for each cylinder, right? Seems weird that they would both fail at more or less the same time.
Is it possible that something in the points area could be misadjusted, fried or shorted to cause the symptoms you're describing? Maybe caused by a dunk in the water?

vanend · #8 Unread post by **vanend** » Wed Apr 25, 2007 8:32 am

revcbl - you are correct, two coils, one condensor. it would be strange if both coils went out at the same time. What is common to both plugs? the points? I have new ones but have not put them in yet. could the points plate be shorting out? is there a way to check?
thanks again, sorry it took me so long to get back to this thread but weather has been very nice here in NC and I have another bike that does run . . . . I'm so ashamed

mydlyfkryzis · Fri Apr 27, 2007 3:57 pm

It's actually 2 condensers. They are just on a single bracket.

Witht he ignition on, you have 12 V going to the coill This is the black wire with white stripe.

The wires coming out of the coil go to the condenser and then to the points. The points ground out the coil on closure. When the points open, the magnetic field generated in the coil collapses and generates the high voltage spark. To check this, using a volt meter, open the points. The movable contact should have 12Volts on it. When the point closes, the voltage should go to zero. When you manually open and close the points, you should generate a spark (on the high voltage side) on the opening of the points.

If you do not have 12V at the points, you may have a broken or shorted wire where the wire passes through the rubber grommet between the point cover and head. The wire here is known to get brittle and either wear through the insulation and ground the wire or break inside the insulation and not provide the 12V to the points.

Since you have 2 complete and separate ignition circuits, it is odd that both failed at the same time.

revcbl · #10 Unread post by **revcbl** » Tue May 01, 2007 2:10 pm

Took me awhile to get back to this as well. When I wrote that, I was thinking the 360 was more similar to my cb750-- points down low, and thus possibly dunkable. It would take one heck of a puddle to put the 360's points underwater-- more of a lake, really-- but I guess they could still get wet.

If you have a manual, it would probably be worth following the procedure for static timing with a light bulb hooked up. That should tell you if things are opening and closing and getting the volts to the right places at roughly the right time. You can also see the spark at the points (if it happens), and at least check the points/timing off the list of possibilities. New points certainly wouldn't be a bad idea, condensors, too.

Beyond that, what mydlyfkryzis wrote makes sense. I'm going to tune up my 360 this weekend (if I don't just go riding instead). I'll let you know if I see anything else. I do think you're on the right track with trying to figure out what the circuits have in common, but nothing occurs to me right now.
Good luck and don't give up.