From:Mark Hill e-mail:hillm@canton.edu
Subject:Cam timing in the Great White North Date:Wed Mar 16 22:30:17 2011
I am mailing this tool that I made off to the Great White North tomorrow along with some final bits of a nice, complete, original Deluxe engine. Anyone who has ever looked at the camshaft timing procedure for Deluxe or KJ has probably shaken their head and said, what the hell? Put the E or the X or the P or whatever in the window and install the idler gear as the number 4 exhaust tappit just closes. Pretty archane. So, if any of you Henderson guys ever put a wheel on the crank and actually mapped the opening and closing of the valves... The point to all of this is to drum up some constructive ideas. We take for granted that whoever stamped the flywheel actually put the marks in the correct spots. Recently, out of utter frustration, dealing with an issue of magneto timing, I bolted the flywheel to the crankshaft, indicated in TRUE top dead center and indexed the flywheel in increments of 5 degrees. That's right - I actually machined light notches into the flywheel indicating before and after top dead center to the tune of 40 degrees before and 40 degrees aft. I will post a pic of this flywheel and crankshaft procedure if people want to see it. The point is, zero on the flywheel or TDC was a hell of a long ways off from where it was stamped at the factory. This got me thinking. If TDC is not stamped where it is supposed to be, I can't take for granted that the exhaust lobe timing mark is where it is supposed to be. And, by the way, where is it supposed to be? The Excelsior v-twin bulletins are excellent for providing accurate cam timing data, as well as most of the Indian data. You guys know by now I really don't care about Harley Davidson that much. I made this tool so that true TDC could be indicated in, especially with the Deluxe, as it has the removeable plug in the top of the cylinder. As a group, we can start checking when valve opening and closing events take place and share this data. It's important. i got my butt kicked with a Militaire cam timing. Yes, we all know that if you don't know the start timing, split the lobe separation angle (LSA), and work from there. I'm here to tell you the hey diddle diddle split down the middle didn't work worth a damn on that engine. I went back to the factory timing marks and the bike ran as if the cam was retarded, and it was. But it's where it ran the best. When I made the tool, I designed it so that you could actually slip the idler gear in place and not have to remove the wheel. If you're building an engine with a fly wheel and crankshaft not from the same motor, you're crazy if you trust the factory marks. Which brings us to the infamous henderson timing gear with its half tooth extra broached key slot. Count the number of teeth on your crank gear. You'll come up with 24. 1 tooth equals 15 degrees. Half a tooth should be 7.5 degrees. That's a lot to change the cam timing. Yes, I read the bulletin, but it's vague and it doesn't offer hard core data as to where things should be. If enough of us get together and map this, I think it would be beneficial to all. Ever wonder why some bikes just run better than others? Tag, you're it Barry. Tool and the last bits are on their way to you. Mark