Topic: OK, this is weird

[Patrick]

I thought I was out of stuff to fix. MY K5 750 was running beautifully. Then....

I've been running my bike every day this week. I went out this morning for a ride. I started the bike, no problem. I'm idling it, letting it warm up... and it stops. It won't start again. I pull the number 4 plug. It's wet, but not firing. I pull the number three plug. It's wet, but not firing. The kill switch is in the on position.  I have juice across the main fuse. I have juice coming from the points, alternately. I have juice to the coils.  So I don't think the kill  switch has gone bad. Where has my fire gone? Can both coils go bad suddenly and simultaneously? I haven't messed with them.

I thought I was out of stuff to fix. My '75 obviously had another idea.

I picked up a 1979 Yamaha XS11 last weekend that I plan to restore. My son thinks it may be a case of jealousy - sibling rivalry.

I'm hoping for a more terrestrial answer.

Any suggestions? Thanks, y'all.

Patrick

[eurban]

Patrick-  Check for spark by holding a plugs business end  (plug still connected to the wire) next to the engine case and looking for a nice spark when you crank over the engine.  Use a good clean spark plug to confirm a spark problem if the one from your bike gives no spark.  No spark would indicate an electrical/ignition problem.  Check for voltage at your coils. check points etc etc.  If your battery is in poor condition or your charging system isn't working properly you may not have enough juice to spark correctly at idle, particularly at a prolonged idle.  You also may have a too rich condition at idle (did you leave it choked too long, is your air cleaner clean, is your idle mix adjusted correctly???)  These things may lead to a fouled out plug.  If so clean em up and try again.

[Patrick]

Hi Eurban,

I pulled plugs on the three and four cylinders and held them up to a bolt on the valve cover. No spark. The plugs were clean, just I used a new plug to check the spark anyway. Not a twinkle. The air filter is a K&N and only maybe 1,000 miles on it. The plug caps are new and have only been on the bike about a month. I get good juice at the coils and off the points. I checked the kill switch by checking the juice to the coils, and when I put it to the off position it stops the juice and at the on position the juice is good. The plugs are finally burning really well, a light tan across all four. The charging system has been completely gone over this year and the bike has been charging very well. That's what makes this so weird - and frustrating. I've been riding the bike for two years with a few things just a little off. Running a bit rich, chaging system just alittle weak. But now, after futzing with it all summer, everything was good. Everything was very good. It was charging and burning right, starting on the first pop and running and idling very well. I finally had everything right. Now this. I am going to pull the coils and clean off the bracket, the mounts and the coil grounds and see if that makes a difference.....

[cbjunkie]

check the wire as it enters the coil - these connections are gimpy IMO -
you say the plug caps are new - but not the wires??

if you suspect the coils or the wires, don't forget to check out your options with Jeff at Z1 Enterprises.

best,
junkie...

[lsutton]

Did you check the spark from both coils?  If neither coil has an output, check the ground at the dist. points and the black/white wire from the coils (both b/w wires should connect together and run to the ign. sw.)   Maybe....      Lee

[Patrick]

Problem solved. I picked up a set of coils from a guy near here with a small herd of old CB750s. Plugged them in and it fired right up like nothing was ever wrong. I suspected before that the coil feeding 1 and 4 was getting weak as I had to unscrew the air screws on those carbs more and a full turn more than the air screws on 2 and 3. Seems like it was a snowball thing. One going bad shorting the other, maybe. I don't know. I just know I'm on the road again. Now I have to start with the air screws all over again. That, however, is a much more managable problem.

Thanks for the feedback guys. And, it kind of surprises me that no one offered me any cheese to go with that whine.....

Patrick

[cbjunkie]

heh...

sir, may i offer you a little string cheese? only the finest, individually rolled between the thighs of swedish virgins...

[HondaMan]

Problem solved. I picked up a set of coils from a guy near here with a small herd of old CB750s. Plugged them in and it fired right up like nothing was ever wrong. I suspected before that the coil feeding 1 and 4 was getting weak as I had to unscrew the air screws on those carbs more and a full turn more than the air screws on 2 and 3. Seems like it was a snowball thing. One going bad shorting the other, maybe. I don't know. I just know I'm on the road again. Now I have to start with the air screws all over again. That, however, is a much more managable problem.

Thanks for the feedback guys. And, it kind of surprises me that no one offered me any cheese to go with that whine.....

Patrick

Oddly enough, I have seen this happen to both coils at once pretty often. I'd say Honda's electrical company's engineers are pretty good at calculating coil insulation life.   

[nickjtc]

heh...
sir, may i offer you a little string cheese? only the finest, individually rolled between the thighs of swedish virgins...

Would that be low or high fat string cheese....? Blonde, brunette or redheaded Swedish virgins.....??

[cbjunkie]

i dunno - Hondaman's choice. 

[Patrick]

Swedish virgins, huh? Got anything a bit more exotic? I was thinking far east, maybe Thailand.

I actually was considering adopting a Vietnamese girl. My wife, however, ever unreasonable, said that a 23-year-old girl doesn't need a new father.

And I was so looking forward to bath time......

[cbjunkie]

Woody ? ? ? Is that YOU?

dunno bout you - swedes are plenty exotic for me...

[nickjtc]

Swedish virgins, huh? Got anything a bit more exotic? I was thinking far east, maybe Thailand.

I actually was considering adopting a Vietnamese girl. My wife, however, ever unreasonable, said that a 23-year-old girl doesn't need a new father.

And I was so looking forward to bath time......

...then at bath time you could at least ask "Who's your Daddy???"

[bryanj]

Being a synic i suspect that the real problem was that the feed wire to the coils wasnt plugged in right and when you changed em you pushed it in father. Whilst it may be possible, and strange coincidences do happen, for both to go totally at exactly the same time is in the high (like winning the lottery) numbers

[HondaMan]

i dunno - Hondaman's choice. 

Brunette. With long hair.

[Sam Green Racing]

Is that on her head as well

[Hyseman]

Who cares

[cbjunkie]

Brunette. With long hair.

yes.