Rotary Valve Alignment

[SurfBeat]

After exchanging my crankshaft and thinking I did everything right, when I dropped the engine in the hull yesterday, it would not start. (crank/yes - start/no)

Even though I am only a Shade Tree mechanic, and an incompetent one at that, since I had spark I knew it had to be a fuel flow problem when I noticed no fuel flowing to the filter bowl.

I checked my fuel selector and lines. All were fine.

Next I pulled the Impulse line from the carb to the engine and noticed no suction, but a tad of exhaust.

When I noticed an oil leak, that gave me the excuse to double check the way I aligned the RV, so rather than breaking my knuckles trying to get to the oil lines, I quickly jerry rigged a pulley and had the engine of of the hull in less than 45 minutes. Aplaud!!!!

I removed the Rotary cover, dropped a pen in the MAG cylinder port and quickly noticed what I did when I aligned the RV last week: I aligned it with the PTO cylinder TDC, rather than the MAG port. (I must have had the engine turned around and did not pay attention to detail.

To be sure I do the alignment right, I am enclosing a couple photos to show the exact postion where I aligned the RV: 130 BTDC/65ATDC.

I find the instructions confusing because after making the requisite marks, it is impossible to put the top edge of the RV at the 130BTDC and the bottom at 65ATDC.

So hopefully, the photos will provide an example of exactly where I now placed the RV after opening to TDC on the MAG cylinder porthole and aligning @ 130BTDC and 65 @ ATDC.

It is 4:00 p.m. here in CA, so, hopefully someone will let me know before the sun goes down whether I did the alignment correctly this time.

 

[Dr Honda]

OK... assuming you have the MAG piston at TDC... you are close for 130/65@147 cut-out. But, as you can see, you are about 2 degrees off. Flip your valve over to see if it's closer. The cutout in relation to the splines is not symmetrical. Since you had the crank apart, the exact position of the splines on the rotary valve shaft aren't in the same place, and you can't always count on the front of the valve still being the front.

I guess I should make a "how to" post on setting the valve. This subject confuses a bunch of people, and not all the service manuals are clear on how to do it. (bad pictures in the book)

 

[SurfBeat]

Dr H:

To begin with, thanks for taking the time to promptly respond to my question regarding RV alignment. Myself being a law skool' grad, one would that I should be able to follow written instructions. That clearly was not the case in the instant matter.

My confusion, as well as I presume others, probably relates to the fact that the written instructions are not clear.

1. On the one hand, instructions state to: a) set the MAG port to TDC; b) install a Degree Wheel (DW): c) align the 360 degree mark to the bottom of the MAG side of the Intake Port; d) then mark the opening point on the crankcase for the specific SD model.

2. While ensuring the MAG port is set to TDC; b) ialign the 360 degree mark to the top of the MAG side of the Intake Port; d) then mark the closing point on the crankcase for the specific SD model.

3. Position the Rotary Valve (RV) on the Rotary gear so its edges align with the timing marks as set forth under para's 1 & 2.

Tony, para's 1 & 2 were lucid for me, however, in my case, I got confused with respect to Para 3. In other words,, the instruction indicates that the RV is to "be aligned with both timing marks." I interpreted that to mean that the RV is to be installed between both marks, however, as set forth in my photos, which you opined sucked, (explain so I do a better job next time) the RV IS NOT aligned between both marks.

I rambled just in case you want to pull some of the language from this Psot when you draft an instructive Thread on this issue.

Photos would also be helpful, showing examples.

As always, thanks for your prompt and very helpful advice.

 

[seadooya]

sweet pics, man. Either flip the disc, or "rock" the pto, double-check ur at TDC, chief. Its not so much, for the open mark to be close, but is for the closing one, to be dead on..65*