Pickup coil question

[dbeardslee]

Randy - What do you use for a lubricant? I just did that on the original (cleaned with brake parts cleaner, and lubed with WD), which is part of the reason I want to replace the pickup assembly - a little too rusty for my tastes, but moving freely. I took the governor out and cleaned that up too. I checked the governor with the advance plugged and it seems to be working perfectly. I'm still having issues with that low rpm stumble (I've got it where it only happens between 1.5-2k rpms). It runs perfectly cold, but when it gets really warm (not just warm - really warm - maybe 15-20 minutes running) it starts it's shenanigans again. With all I've done to it trying to track down the gremlin (valve clearances, carb boots, pickup coil wires, wiring connectors, and many, many, many trips into the carbs) the only thing that's affected the problem is when I've moved the pickup coils around. I've checked the resistance at the TCI and everything is in spec, and the readings don't change when I move the wires around, but still, I suspect the pickup coils themselves. It looks to me like one is getting hot and malfunctioning. I read somewhere (haynes manual?) that even if they pass the tests, they could still be defective. For $28 I'm going to find out.

[bikerphil]

Hey DB, have you swapped out your coils to eliminate that from the equation? I had Mikes XS coils on my 79F and one day riding along, one coil just up and quit. It tested fine with the ohm meter but wouldn't work worth a dam on the bike. JAT

[dbeardslee]

Phil - I was kind of saving that one as a last resort, but you may be right. I've changed the wires, and tested the crap out of them, but no actual swap yet. The other thing I did in my search for volts was to solder the wires together where the ballast resistor used to be, so I can't put old one's back on now. If this fix doesn't get it I may just bite the bullet and get some of those 45k volt coils mikes is selling now. I hadn't heard of the mikes coils failing 'till now, so definitely thanks for the heads up on that.

[bikerphil]

Yep, that bad coil I had first quit working all together, then it came back and worked erratically. I put some XJ non-ballast factory coils on and now it's fine. I hope you find the problem soon. A stumble in that RPM range can be dangerous, depending on how bad it is. Good luck.

[dbeardslee]

Alright, Phil. You gave me that little nudge that pushed me over the edge, and I just ordered a set of the extra hot Mikes XS coils. I even sprang for the two-day shipping. I'm pretty sure at this point that it's something in the ignition, so if the pickup coils don't fix it hopefully the ignition coils will. I'm gonna be having dreams about coils . One way or the other I'd REALLY like this problem gone by the weekend - a month of chasing a gremlin is long enough.

[randy]

As far as that bearing, WD40 won't do much but free it temporarily, it will dry out quick, especially under heat. The way i did mine, I removed the bearing and soaked it in oil overnight. It's got metal seals both sides, but oil will seep in if you give it time.

[dbeardslee]

Randy - That sounds like a good idea. I've still got a tub of oil left over from when I soaked my clutch disks. Just remove the bearing assembly, remove the electronics from the plate and drop it in?

[randy]

Yup. Then work it around a bit the next morning, make sure it's free.

[dbeardslee]

Randy - That's what I'll do.

Phil's got me thinking about ignition coils, and I'm wondering - for the last year or so I've had Iridium plugs (BPR6EIX, 5K ohm resistance is all you can get for the XS) in conjunction with 5k ohm caps installed. Recent tests I conducted show that with that setup rather than having 15k secondary resistance (plugs included) I would have had 25k ohm secondary resistance with the double resistors. I wonder if that could cause or contribute to the failure of an ignition coil?

[randy]

I don't think the higher resistance will contribute to the failure of a coil, BUT it will reduce the spark output. Run resistor caps OR resistor plugs, but not both. No resistors at all is my preference.

[dbeardslee]

I recently replaced the 5k ohm caps with the non-resistor variety and when I measure that it shows the 15k ohm secondary resistance that the coils are supposed to have. If it winds up being a defective ignition coil, I just want to make sure I don't encounter another failure with the new ones. Just looking at the pictures they appear to be better quality coils than the $34 variety. For $69 a pop they better be .

Whatever the problem is, it has something to do with heat. I remember many years ago my dad was driving a Jaguar from Cincinnati to Indianapolis. The coils in the jag had something inside them that got hot and turned liquid shorting out the coil (can't remember what it was - been almost 30 years ago). He'd pull over and let it cool down, whatever the liquid was would re-solidify, and it'd start working again. Sounds an awful lot like the problem I'm having, except my motor has to get stone cold before it 'fixes' itself.

I'm going to do one fix at a time and then test it to determine if the pickup coils or the ignition coils make the difference. If neither one fixes the problem I think I'll start looking for a high spot to throw myself off of .

[DiverRay]

If neither one fixes the problem I think I'll start looking for a high spot to throw myself off of

Remember to park the bike first, so someone ELSE can drive themselves over the edge!

[3Phase]

Yup. Then work it around a bit the next morning, make sure it's free.

The dust shields on both sides of the bearing will lift and pop out with a small pick. It's easy to clean the bearing and lightly repack it with some high-temp grease, then carefully snap the dust shields back in place. Unless you like to ford a lot of rivers it should last another thirty years.


Regards,


Scott

[randy]

Not as easy as it sounds. That may be true with wheel bearings (done it) but this bearing is such a large diameter and the shield is only about 1/4" wide. Try it

[3Phase]

Not as easy as it sounds. That may be true with wheel bearings (done it) but this bearing is such a large diameter and the shield is only about 1/4" wide. Try it

I did. Mine was semi-seized and full of rust because a P.O. thought that because the bike had a snorkle on the airbox it must be a submarine.

I stripped the dust shields and cleaned the bearing. One of the shields bent while I was removing it but a small ball peen hammer and a flat-tipped punch put it back in shape. You could even leave the dust shields off. There is no dust inside the left engine cover barring an exteme mechanical failure (the cover gets broken or falls off). The bearing never makes even one-quarter revolution and it's nowhere close to its RPM limit when it is moving. It's pretty solid.


Regards,

Scott