Hello again ,
The saga continues... I’ve got my bottom end and my top end done and now I’m trying to set the timing on my 1976 DT400 restoration. I’ve used a dial gauge to find TDC and backed off to 0.15mm BTDC just like the Yamaha service manual says. The problem is when I try to line up the timing mark on the flywheel with the mark on the stator, the stator is no where close to where it should be. If I’m supposed to line the flywheel mark up with the pulsar contact point (if that is the stator reference point) it’s not even close. If there’s a different mark on the stator it’s not visible. I put a mark on the case once the correct timing point was determined for reference once the flywheel was off again. After taking the flywheel off I don’t see how the stator can be turned to get close to lining things up. I hope this makes sense to someone. Any suggestions?

Check your timing specs. Should be 2.9mm +/- 0.15mm

If that's not the problem, take pictures so we can see what you're seeing.

As Mark T said. Also be sure to roll it back farther than 2.9 then bring it forward to 2.9. I usually do it a couple times to be sure I have it right. Needle on the gauge spins quite rapidly with a small turn of the crank!

Thanks for getting back to me guys. I really appreciate it. I’ve seen 2.9mm in the manual before. I think my biggest problem is I need to learn how to use the dial gauge. When I first got it, the part that screwed into the spark plug hole was too long and didn’t allow the moving probe to touch the top of the piston. So I cut it off to make it shorter. I cut it off too short so that the whole gauge lifted out of the threaded base when the piston approached TDC. I then put a few washers between the gauge and the base and drill and tapped a set screw so that the gauge was stable. But now I don’t get measurements anywhere near 2.9mm. Bottom line: I don’t know what the heck I’m doing. I’ll have to do some more research and figure out where I screwed up. Here’s a picture of my Frankenstein dial gauge:

With my dodgy methods & DT400 being CDi & all that, just put the stator plate back on where the original screw have left a mark, which will be not far off the center of the slots then fit the flywheel VERY TIGHT--not joking lol, then stop worrying about it unless you know the system has a problem. Could strobe it to a white mark you could put on the flywheel & non moving case--anywhere thats convenient so long as the marks you make are at 2.9 btdc & see how it looks. Might move around a little but not much.
Just looking at this link i see it has the old style trigger coil so might not move at all from 2.9 except to start on retard but you won't see that on the strobe as drops back just before it stops, or if ya real lucky to get it idling that slow you could see it showing.
www.babbittsonline.com/oemparts/a/yam/50...c-d-i-magneto-400b-c

Thanks. I thought about doing that but being a rookie to this restoration process I was trying to do everything by the book.

Yep, if all else fails then read the instructions lol. Works for me.