Ran good then the left side slowly died.

[cmyoch]

My neighbor has a volt meter and I plan on borrowing it tonight to check my coils. I cleaned up the points a bit but I'll do it again to ensure they are not marred or pitted. Since my starter gear is stripped, it's a kick only bike for now so I'll have someone kick it as I watch the spark. Do you advise I get brand new plugs for this or would my existing plugs with carbon on them be sufficient given the low miles put on them?

I followed the adjustment section of the carb guide which helped me get them tuned properly last weekend. I never heard of the dead cylinder methed until now. It's effective. I'll have to study the rest of the guide this weekend.

I'm hoping to find the issue this weekend while it's still cold so I'm ready to ride soon!

 

[retiredgentleman]

If your ignition coils are original, I would recommend you replace them with a new single coil with dual output. As XSLeo mentioned, your spark will go from 10K to 30k or better. A coil with 4 ohms or greater primary can be used with points. If you want to use a single coil, you simply connect the 2 sets of points together in parallel, and disconnect one of the
capacitors.

I use the dead cylinder method to adjust the air/fuel mixture screws. I use a simple u-tube manometer to sync the carbs.

 

[cmyoch]

I have my neighbor's meter and I plan on testing them this weekend. So what single coil are you referring to? Is it listed on 650 Central or Mikes XS?

 

[retiredgentleman]

There are several ignition coils that can be used with points:

Mikesxs #17-6822, ( 4.5 ohms) has 37K volts and is reasonably priced. If you decide to later change over to a Pamco, this coil will work just fine.

H.D. OEM 31609-65A

Custom Chrome #17130

Accel Power Pulse #25507

The Accel #140403S, 3.3 ohms, (non CDI) can also be used with points, but you would need to use a 1.3 ohm ballast resistor in series with the primary. I used this coil for a year with a ballast resistor and with the points tied together in parallel................it worked very well. I changed over to a Pamco ignition, removed the ballast resistor, and used this same coil for the last 3 summers.

 

[cmyoch]

I've had a busy week so I didn't get my coil ordered yet. I plan on doing that this evening. I went ahead though and checked a few things on the bike here's what I have:

Right Coil: 4.2 Primary, 8.0 Secondary
Left Coil: 8.2 Primary, 8.6 Secondary

6.0 ohms at the stator

Brushes are decent but I plan on ordering a pair since they are cheap enough

12.23 volts at the battery.

All of this was done with the bike cold and hasn't run in a week.

 

[XSLeo]

The right coil the 4.2 primary is ok, The left at 8.2 isn't. On your secondarys, is that 8.0 and 8.6 on the 200 ohm scale? If so thats not so good. If on the 20k scale then thats not so bad.
The 6 ohm rotor should work ok. New brushes is a good first step on the charging system.
12.23 on a week old charge is ok.

 

[cmyoch]

Yes, it's on a 20k scale. I am assuming my left coil failed at that resistance level once it warmed up. Regardless, I'm ordering a new set of coils. You said 6 ohms on the roter is ok, what level would be ideal? I'm trying to test everything I can before I place my order so I'm not stuck troubleshooting and replacing single items for weeks on end. Oh, and I'm going to go ahead and put in a new set of plugs while I'm at it. Maybe the irrodium plugs. I don't know yet.

The weather is getting nicer here in the Midwest and I'm itching to ride!

 

[gggGary]

5.3 is factory spec but meters vary usually bad is less than 5.0 (insulation going bad) or open circuit (broken wire).

 

[cmyoch]

Well good. That's an expensive part. Coils are going to be expensive enough...

 

[ReycleBill]

I tried the irrodium plugs and while I've no doubt the claims are true I don't think most of us will notice a 2 HP increase. Sure, the bike will have 2 more horsepower but we'll not notice it. My advice, take your old plugs to your nearest auto parts store, buy two new plugs there, gap them to 28 thousandths (or thereabouts) and save yourself a few dollars.

And remember: anything that can be converter to off-the-shelf auto parts items will save you money both short and long term, and allow you to more easily fix breakdowns while on the road. That includes XSLeo's Chrysler regulator swap which I would have already done had I not bought and installed a complete Yamaha system the day before I joined this forum last year.

 

[XSLeo]

On your coils the 8 and 8.6 is 8,000 and 8,600 ohms. Big difference between 8.6 ohms and 8,600 ohms. Thats not bad on that part. The 8.2 ohms on the primary is bad.
On the rotor spec gggGary has it right. My book says 5.25 + or - 10% thats 4.7 to 5.7. My Clymer says 5 to 7 ohms. As long as your in the ball park you should get some charging.
One thing when you check for that low a reading you should check the meter by touching the leads together first. This will give you the ohms of the leads. You need to subtract this from the reading you get when testing the part. Most leads can test to .5 to.8 ohms.
If your test about that the 6 - .5 = 5.5, 6 - .8 = 5.2. So be sure you do the check. You can see it does effect the actual ohms.
I have one that tests ok at room temp, but as it warms up the resistance goes up to around 8.5 to 9 ohms. At this point it stop charging.

 

[cmyoch]

I am going to order my coils tomorrow and get them installed. Once she's running and warmed up, I'll re-test my rotor again.

RecycleBill, thanks for the advice for converting to on the shelf auto parts items. Is there a sticky or good post somewhere advising what can be converted besides the regulator and rectifier? Are there spark plugs you can get from the parts store that work with points? How about coils? I'll start my search through the forums tomorrow when I get some time.

Thanks for double checking my numbers guys!

 

[ReycleBill]

RecycleBill, thanks for the advice for converting to on the shelf auto parts items. Is there a sticky or good post somewhere advising what can be converted besides the regulator and rectifier? Are there spark plugs you can get from the parts store that work with points? How about coils? I'll start my search through the forums tomorrow when I get some time.

Thanks for double checking my numbers guys!

There are plugs, I just can't remember the numbers.

Coils I'm not sure about. I think some of the two cylnder Wisconsin engine coils might work but they won't mount in stock brackets. They will mount in older stock Harley brackets.

I'd like to see a thread on convertible parts.

 

[cmyoch]

I put a new set of coils with new plugs on it last night and she fired right up! On the test ride my idle rpms kept jumping to 3k which I believe is a carb adjustment because that seemed to fix the problem last time. I plan on adjusting them plus checking my points gap when I get home from work today. Thank you guys so much for your advice and giving me the confidence to do this myself. I'd be totally lost here without you.

Now on to swingarm bushings, petcocks, and steering bearing(s). At least now I can ride it a bit by the weekend!