Timing retard/advance/Pamco

littlebill31

littlebill31

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Well, I have tried everything I can think of, but the timing is still too advanced.

Fresh top end rebuild
Brand new Pamco, advance rod, springs, weights, coil, wires plugs, everything, complete kit from Mikes.
Advance mechanism snaps back like it should.

Not sure what is going on, but at 1,200 rpm idle, you can see where the line lands at full retard on the Pamco.

I took everything apart, double checked, took off the rocker cover and checked the cam alignment. Dead nuts, 12 0'clock on TDC line.


....
 
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Not sure if I read it wrong but have u tried loosening the pamco disc and turning it slightly to the right or left
and then retest.A 1/16" movement makes a big difference.
 
Yes. That is the point of my question.
Turning Clockwise is advance and CCW is retard. It is at full retard and still too far advanced to be between the "F" marks.
I cannot retard it enough.
If I give it throttle it will pass the full advance mark, and I really don't want to hole a piston.
So I am trying to find any help from folks who have maybe dealt with the same issue.
 
No, I think he meant the Pamco rotor mounted on the advance rod. Sometimes there's a little play in that mount. There could also be a little on the advance mount too. Have them both turned hard to one side of that play range and it could add up.
 
I have same set-up on my 77,check the rotor nut is tight, not sure if it matters or not but look at your mechanical advance
from idle up to approx 3000 rpm, it should start to open the flyweights approx 1700 rpm and be fully open at around 3 grandma my have
the springs to tight.
 
Was gonna start new thread but here seems appropriate...
When you find the correct placement of sensor plate, is it common practice to loctite screws so timing doesnt stray due to a lossening screw?

Thanks in advance
 
If you mean the backing plate, where you do your timing adjustment, I'd say no. You may, as I found out, want to tweak your timing setting a little in the future. I installed my Pamco in cooler weather. When it got really hot out, I noticed a little pinging, so I needed to retard my timing setting a hair. Over the course of a couple years, I think I tweaked the setting 2 or 3 times before I was finally satisfied with it.
 
I knew it. I knew it.
Another quality shit part from Mikes. The fucking thing broke unscrewing it.

Cheap junk that they won't stand by or return.

IMG_2057.JPG




IMG_2058.JPG
 
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So after numerous emails, Mike's has still not replied about the advance rod snapping off. All I want to know is if I can get a replacement or something. But I guess that is too much to ask.
Funny how their reviews are vetted on both their site and Facebook pages. Only the good ones show up.
 
Thats unbelievable, the metals there using are soft compared to the original stuff Yamaha made.
Find a used unison Ebay,shouldent be hard to find.Prob someone on here may have a spare.
I have had a few bad parts from XS650 Direct here in Canada but they always helped me out.
Different owner but same parts.Goodluck!
 
So I used a degree wheel and piston stop to verify TDC. It's dead on.
I put an original advance rod in, held the rotor tight as instructed and set to 7ft/lb. It is still too far advanced. The line is still to the left of the "F" area with plate fully retarded. It will start, but breaks up with throttle. Any more advanced and the mule kick happens.
Anyone have any ideas?
 
Just a couple ideas, but this is Pete's department, and I don't want to step on anybody's toes.

1- I've seen a couple of pics posted in the past of Pamco plates, and noticed that the hall sensor was bent a little to one side. Wish I had saved those pics, hard to find that stuff now. Anyways, the sensor is the circled component. See if it's straight, as shown, or bent over a bit. A small 5° offset would show up as 10° at the crank.

Pamco01.jpg


2- Awhile back, I was researching hall switches for a different (lathe) project. This snippet of a budget hall spec sheet shows the ranges of magnetic field strength within which the hall switch turns-on (Bop) and turns-off (Brp). The wide variances shown here are ignorable when building a tachometer, but could be significant if used in a critical ignition timing application. Don't have specs of the switch used on the Pamco.

HallEffectRange.jpg


Well, that's my 2¥...
 
TwoMany,

The variation in sensitivity is not a significant factor in the design of the PAMCO due to the close proximity of the sensor to the rotating magnets and the cone shapped sensitive area above the hall device. In other words, a stronger or weaker magnet or a more or less sensitive Hall sensor will not operate sooner or later. The Hall sensor operates when the magnet crosses the edge of the cone. The exception to this could be a rotor that is not seated properly on the cam shaft boss thus raising the magnets higher In which case they would trigger the Hall sensor cone sooner necessitating an adjustment of the plate in the retarded direction, so check for any manufacturing irregularities that prevents the rotor from seating properly.


Also, bending the legs of the sensor is not reccomended as you risk breaking them or worse, breaking the seal of the case to the leg may allow contaminants to enter the sensor case which may not cause an immediate failure but cause a failure at a later unpredictable time.
 
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