Well, here is my thread
http://forums.sohc4.net/index.php?topic=82270.0The following is NOT going to answer your question - maybe just give you food for thought.
I started it a couple of years ago and then realized I was not going to be able to post in any kind of timely fashion like others. I did take off on the build, and did consult with the forum frequently, bought Hondaman's (Mark Paris) book, etc., etc., etc.
I thought I would re-start the thread and then gradually add in the process steps to see what people thought, answer questions, etc., but I did not really get to many responses and most of the guys on the form who are running "F's" I have already consulted with in one way or another anyway, like Jerry in Colorado, Don in New Jersey, Mark in Colorado, etc.
I got cash again for Christmas like I did for the last two Christmas's for my project, and think I am closing in on the home stretch. I joined the VJMC and started mixing with other VJMC members, went to the west coast rally, etc., and am kinda hoping I can get it together for the Classic Motorcycle Show at Barber this year in, I think, 1st of Oct. 1st 100 registered classic display bikes for the VJMC get into the Barber event free.
I wanted to stay with the stock muffler because I liked the look as the muffler is LONG, and just looks right on the F. My original muffler "looked" good from above but had several rusted out holes underneath. I ended up buying a stock replacement from eBay that looks really good. All that said, I also purchased Don's glass-pack muffler as it was reasonably priced, this was before I found the one on eBay.
So after all that I think I'm going to start out with Don's muffler and see how she goes. There is talk about one of the problems with the "F" is all of that additional weight on the right side i.e. 4into1 exhaust and the huge muffler. I was never going for EXACTLY period correct (100 point restoration), I was going for obviously the CB750 look but wanted to make it ridable, maintenance free (more free) and if possible a little faster then stock.
So enter the Hondaman low cost improvements, timing advance, etc. And if I'm going to minimize the asthma, why burden the exhaust with so much back-pressure (stock exhaust). OK so that the current thinking, but its not running so I still have the stock muffler to fall back on. I'm hoping per Don that his muffler sounds good at basic idle, normal cruise, but starts to pick-up the pitch when you crank her on, we will see.
So sorry for all of the dialogue and getting back to your issue with the timing. This WAS the most complicated process/change I undertook. It took me awhile to understand there are/were manufacturing variations "back in the day" and how that impacted this issue of advancing the timing in particular. You could rotate/reverse the cam sprocket and get a different reading, so for instance there is a front and back. I don't think the factory intended that, but there is due to variations. The notch on the end of the cam is not exact, etc., etc., etc.
The other problem I got into was the kinda of double speak, in other words was I advancing or retarding, how was I changing duration, what about the variations between 1-4 and 2-3, it started driving me crazy. I think I went back and forth with Mark for over two weeks before I finally FULL understood exactly what I was doing, were I should be measuring, etc.
What I finally did, once I understood the measurement issues, direction I wanted to go, etc., I tried to duplicate stock, what I had when I took it apart. I think even some of the questions I had about direction also got resolved once I went back to stock and tried to duplicate "stock."
I also had to resolve the 10 thousands as that's what I had removed from the head. For what its worth I was thinking it was Mark who recommended I not remove anything from the cylinder's just buff it up.
Somewhere along the way I finally got it, took me weeks to fully wrap my head around what was going on. The forum kinda helped but most guys were/are not getting into this kind of detail. I did find several other generic web sites that helped me full grasp the details of spec'ing the cam and advancing the timing.
So 1st you have got to find TDC and that may not, is probably not with the point plate 1-4 on the "T" and the end of the cam with the horizontal line, lined up (slightly off). Once you got that figured out, and you understand what your original motor had in terms of advance, assuming like it was in my case, stock from the factory, then you can start working the slotted cam sprocket to advance, in my case 5 degrees.
So for what its worth, at my advanced age, I cannot remember the detail!! I would have to just get back into it again and start trying to re-wrap my head around it. What I THINK I did was to adjust to the correct TDC and advance by 5 degrees. For sure nothing is hitting, BUT its not running yet!
