Charging issue

David Toll

Reliving my youth?
Top Contributor
Messages
587
Reaction score
1,778
Points
143
Location
Gold Coast Australia
Got the SE running but I have a couple of issues of course. The electric start has come good and fires her up almost immediately. She was ticking away when I removed the left plug and found no change in revs - she must have been running on one cylinder. Sounds good like that but I don't think it's what I want. Checked the plug for spark and got none so I changed the plug and she fired up on both. Seemed to run fine and responded appropriately when I removed the cap from each cylinder. Left her overnight fired her up next morning and had the same issue - left cylinder wasn't firing. Checked the plug - no spark again. I took the plug from the running right side and put it in the left. Replaced the right hand plug with another spare. Fired her up and left cylinder ran but now, no right. Intriguing! Can't be another bad plug?
Began to check the electric system and started with the rotor. No magnetic "slap" with the key on. The resistance between the rotor strips was only 1 ohm. My leads read in at 0.1 so that means that there is a reading of 0.9 between the rings. Checked continuity on the rings to earth and got a 1 on both.
I assume that I am doing this right.
Resistance - ignition off, multimeter set at 200 ohms, blacklead on outer ring, red on the inner ring. The readout stays on 1.
Continuity - selected on meter, red on ring, black on earth - reading 1
So continuity appears to be OK but resistance is nowhere near 4.
Getting 11.9 volts at the brushes (new) from a 12.5 battery charge
Battery voltage doesn't seem to increase as I increase the revs; it hangs around 12.55.
The non- firing cylinder could be carbs as I haven't done a lot to them in terms of synch though they were "drag through" checked with a card. Jets, floats and needles are new and carbs were cleaned a couple of times pretty conscientiously. Rectifier and regulator are also new as is the ignition switch. I fear it might be the rotor that is giving me grief what with the intermittent and swapping spark and the lack of charge. A new rotor is around $170 so is there anything else I should check before I shelve out the bucks?
All advice appreciated as usual.
 

Attachments

  • IMG_0309.JPG
    IMG_0309.JPG
    210.6 KB · Views: 139
  • IMG_0310.JPG
    IMG_0310.JPG
    212.7 KB · Views: 126
  • IMG_0312.JPG
    IMG_0312.JPG
    198.8 KB · Views: 133
  • IMG_0313.JPG
    IMG_0313.JPG
    193.8 KB · Views: 182
Yeah time to bend over for new or rewound rotor.
What ignition?
I'm big on drying plugs with a propane torch till any deposits are just carbon, then wire brushing the residue off.
If it's oil creating the problem get out and ride it good hard and long, sometimes that's enough to "cure" an oily cylinder. While the plugs are out, might spray in a shot or two of rust buster hoping to free up sticky rings.
 
Hello Gary,
I have standard points and coils in the SE along with a VR115 regulator and a solid state rectifier. Yes the plugs are a bit oily - running rich?
 
A working charging system may cure all the ignition issues.
Sounds like you are oil fouling the RH side.
A stronger ignition may cure it, getting some miles on the motor may reduce oil consumption.
As a bandaid I have used a BP6ES plug (hotter) in an oily cylinder.
Yes synch those carbs. \
Overall it's amazing what a couple hundred miles of hard running can do to "fix" an ornery motor that's sat a for a long time.
 
Hi David! Looks like your headed in the right direction. Not to steal your post but, I know that a point gap set too close will kill a cylinder if a dwell meter is attached. Also that cylinder won't fire if the resistance of the spark plug is too high due to oil. I can't for the life of me, see how a bad Alt rotor can kill one cylinder but not the other, or even both?
 
points clean straight gapped condensers checked or replaced ditto coils wires, plug caps.
Troubleshooting is best done by methodical testing and verifying function of every component, rather than trying to "find" an issue.
Bonus it turns out this is also the FAST way to a good running motorcycle.
Yeah I've spent a lifetime trying it the other way. :banghead:
 
Thanks for the replies gentlemen. I agree with you Thuban, that alternator is an unlikely culprit but my tests show that it is buggered. Mike, I'll check the voltage the coil when I kick it over again - the wheels are off at the moment getting new rubber. Looks like it's going to be Gary's "methodical testing" - stands to reason as the quickest way to get a response from the motor. Sigh..... I was hoping for an easy fix, the old girl sounds great when she's going and I was hoping to dust off my helmet and lace up my boots. Oh well, back to the garage.
Will report back.
Cheers
 
Hello Randy,
After consultation with the people at Gold Coast Motorcycle Tyres & Mechanicals, I settled on the 100/90/19 Pirelli Sport Demon on the front and the 130/90/16 Pirelli MT66 for the rear. Apparently, the Sport Demon shows good steerage, adhesion and wear characteristics for this sort of mid-size motorcycle and the MT66 is a tried and trusted favourite for cruiser/tourers that offers an excellent compromise between stability, comfort, adhesion and wear - at least that's what the guy in the shop said. Expensive though - Front $180/Rear $200 (AUD). Could have shopped around more as I have seen them for as low as $149/$164 respectively online but then I would have had to pay for fitting and balancing anyway. These guys are local and can use my support. If I have issues, I know where they live.
Don't mind spending a few bucks on the tyres for the obvious reasons. If I ever actually get on the road, I'll post my impressions.
 

Attachments

  • Pirelli Sport Demon.pdf
    233.5 KB · Views: 128
Yeah! And what happened to James Dean?? Not on a bike at least!
As for the tyres..... I just walked into the shop and said, "I want some round black things for this motorcycle - stuff that won't kill me."
I do hope they understood. I suppose I could have got something from the Weifang Shengji Rubber Co. but the Pirelli's do sound fast and I wanted something that goes where I'm looking. The experts have assured me that these tyres will outperform my ability and my nerve. We'll see.
 

Attachments

  • IMG_0315.JPG
    IMG_0315.JPG
    213.8 KB · Views: 114
Yeah! And what happened to James Dean?? Not on a bike at least!
As for the tyres..... I just walked into the shop and said, "I want some round black things for this motorcycle - stuff that won't kill me."
I do hope they understood. I suppose I could have got something from the Weifang Shengji Rubber Co. but the Pirelli's do sound fast and I wanted something that goes where I'm looking. The experts have assured me that these tyres will outperform my ability and my nerve. We'll see.

Yeah, you’re gonna like those very much. I went two very different routes on my two bikes, the old XS2 has vintage tread designs and they feel their age, they don’t handle nearly as nice ( but they do look right ). But on my ‘77D I went with modern sport profile like yours and they handle Sooo much better!
 
I was a little worried that the old girl might look like a diva in a mini skirt. I really don't know that much about the dynamics of tyres Bob but the solid chunky tread of the tyres I took off, (shop said they were made in the mid 80's), certainly seemed to put more rubber on the ground than the new set. The tyre technicians seemed to know their stuff and I pay attention to expert opinion, that's why I seek assistance here. I did wonder why they didn't put on a complete set of Sports Demons grizld1 so you could be right. I appreciate the fact that you fellows think I made good choice, makes the pocket pain easier to bear.
Cheers
 

Attachments

  • Picture1.png
    Picture1.png
    847.9 KB · Views: 143
Last edited:
Like Mailman, I used the Dunlop K-70s, vintage tread design, on the XS. I like them, maybe because I haven't tried the modern, "slick", go-fast type of tires. They rarely see anything over 70 mph. I did put Dunlop's, of modern design, on the Honda. But it's a different machine. The modern "slicks", with a rain groove cut here and there, well, back in the day if a tire looked like that, we called them "may-pops". You could smell the air in em'. The modern "slicks" may stick because of modern rubber formulation and tire patch size, but that formulation don't know beans about wet grass or gravel roads or charging issues. :)

Some people told me they had a pix of my wife in their wallet. I didn't believe them , till now.
 
Back
Top