Timing a 66 Yamaha YDS 3

Finishing cleanup of my old 66 YDS 3 and having trouble understanding how to set timing. HELP

 

thats a oldie, i've got no specifics for that but are there points on a plate that can spin ?
and two marks on the flywheel maybe marked "t" and "f" and some mark on the case by the flywheel
thats kind of a generic setup for older points bikes
is that what we got here ?

 

No. There are two sets of points on opposite sides of the shaft. On the end of the shaft is a metal plate stamped l1and l2. There are two adjustments on each set of points. One sets the point gap and the other apparently sets the timing. Setting the gapis fairly simple. My problem is setting the timing. I used a piece of wire in the spark plug hole to determine TDC. Then backed off to an estimated 0.071 inches BTDC. Then set the timing to open the points at that location. Went from not running well to not running at all. Will attempt to attach pix to show assembly. Thanks for your interest and all assistance is solicited and accepted.
Bob

 

No. There are two sets of points on opposite sides of the shaft. On the end of the shaft is a metal plate stamped l1and l2. There are two adjustments on each set of points. One sets the point gap and the other apparently sets the timing. Setting the gapis fairly simple. My problem is setting the timing. I used a piece of wire in the spark plug hole to determine TDC. Then backed off to an estimated 0.071 inches BTDC. Then set the timing to open the points at that location. Went from not running well to not running at all. Will attempt to attach pix to show assembly. Thanks for your interest and all assistance is solicited and accepted.
Bob

 

Attempting pix again

 

OK, you're there--sorta. Yes there are two adjustments on each set of points, one for gap and one for position (timing) BUT if they are anything like my dual-points Norton, every time you adjust the "timing" you affect the gap. (Gotta keep re-checking the gap.) Now then--when you say "set the ponts to open" how are you determining they are open? Visually, or with a light or meter? Visually won't do it, you have to check electrically. If the timing is also given in DEGREES BTDC, get yourself a degree wheel (they are cheap and any place that specializes in truly old bikes sells them) and do it that way. You rig up a pointer, and "zero" the wheel at TDC, move it the specified degrees, and voila! You may also be getting tripped up by an auto advance mechanism. The one on the Nort is BEHIND the points plate and if you don't know exactly what you're looking at you wouldn't know it's there. For doing static timing on the Nort there is a special "collar" that locks the auto advance unit in place. I gave up the practice of static timing years ago, and bought an inductive timing light (the kind you just clamp over the plug wire.) Anyway, final tip on setting dual-points ignition systems: If BOTH sets of points are mounted on a plate that is also adustable, center up both sets, set gaps, set timing to one set USING THE PLATE and then set the other on its own. I would make sure you're not fighting an advance mech of some sort and check timing electrically whether with a timing light or a meter or continuity light. Keep us posted, I'll try to clarify anything I can if you need. I've never done an old Yammie, but I've done timing on BEAUCOUP old dual-points Britbikes. SUHWEET old Yammie by the way...

 

OK, just saw the pics. Get out your book, I'll betcha anything there's an advance mechanism under there. The one on my Norton pivots the CAM around the shaft, thus advancing when the points get opened. There could be something similar hiding under there, and they should tell you how to lock it in full advance.

 

This is all I could find on it:

YAMAHA YDS-3 AND YM-1 MODELS
IGNITION AND ELECTRICAL.
All models are equipped with a battery
ignition system with an individual set
of breaker points, condenser and coil
for each cylinder. The generator is
mounted at the right end of the crankshaft
and the breaker points are
mounted on the generator stator.
Breaker point gap at maximum
opening should be 0.30-0.35MM (0.012-
0.014 in.). The breaker points should
just open when the piston is 1.8MM
(0.071 in.) BTDC on YDS-3 models and
2.0MM (0.079 in.) BTDC on YM-1
models. Ignition timing must be
checked and adjusted individually for
each cylinder. A static timing light or
meter can be used to indicate point
opening and a dial indicator in the
spark plug hole to position the piston.
Timing is changed by moving the
breaker point assembly in the elongated
holes after loosening the two
mounting screws.


I have a short PDF for maintenance, If you want it Email Me and I'll send it to you(900k).

 

Thanks guys. Followed your advise and found that at 75mph and still climbing, this old body turned to chicken. Still have a slight hesitation and burbble but things are so close now and I still haven't tried to fine tune the carbs.
The old girl only has about 3k on the odometer and was last licensed in 1969. I have put it over backwards shortly after getting it and there are some scrapes and bends but overall it's in good shape.
I dug it out when the price of diesel was nearing $5.00 but now that diesel is nearing $4.00 I think I will just continue to catch some wind on my way to work.
By the way, do you have any idea what a bike this old might be worth. Not interested in selling but wondering what my wife's $1200 investment might be worth after 43 years of living with this old coot.
Thanks again. I will continue to watch this site for more ideas and information.

Bob

 

Now I have another problem I have never run into before. Still trying to get the burbble out of the top end and when I came in tonight the bike went to about 6k rpm when I put it into neutral and when I shut off the key it had no effect. Had to drop it into 1st and pop the clutch to kill it. On restart it idled just fine but I noticed a spark jumping between the jug and the choke linkage. When I put a screwdriver close to the jug the spark would jump to the screwdriver even though it was not touching anything for a ground.

Don't know if the two are related but it sure was strange.

Bob

 

You have angered the electrical gods. If it's jumping to the screwdriver without it being apparently grounded, it's probably HV (spark plug) voltage something is touching somewhere it shouldn't. I would take a close look in the points cover again and make sure there isn't a wiring "tab" touching somewhere and take a good close look at the coils/mounts too. Glad to hear you got it running.

 

Well, after a month of trials and tribulations (see post on spark from the side of the cylinder) I have finally gotten to where I wanted to be. Still had some problems in the mid to high range. Took the carbs back off and rechecked everything. Reset the floats again. Cleaned the needle on the other carb and noticed an extra part that wasn't on the first one. It's called a circlip and serves to hold the needle down in the slider. Made a new one from a washer and put everything back together. Took it out and warmed it up. Set the idle and air screws and was off. She hasn't run like this since I've had her. I'm through farting around and am ready to do some serious riding. Thanks to you bigfitz and the others who have responded I think this thread is closed. Again thanks to all who responded.

By the way a special thanks to whoever turned me on to NWVMP. Turns out I rode with John about 40 years ago and he is the one who put my ride back together after my crash. Hope to get with him soon and talk about old times.

 

That is great news indeed. Happy to help, what's truly great about your whole experince is that another GENUINELY OLD motorcycle is back in operation again. One thing to keep in mind going forward: dual-points ignition like that isn't famous for holding any sort of adjustment forever. The first time it starts misbehaving again, check the gap and timing again before you start looking elsewhere. Remember, gap affects dwell, the amount of time the spark plug is actually firing for. Nearly as important as the timing itself, especially in an old 2-stroke. Happy trails Bob, once again that is truly awesome news!