Alright so here's the run-down...vin on motor on the bike is DT1-57739, 1970 DT1. The frame vin is DT1-06641, 68...which matches the vin on the spare bottom end I have. So, I've got a 68' DT1 with a 70' motor in it and 3 tanks. The yellow one is a mystery to me as it has the 68 mounts but shows not a shred of white even sanding down to bare metal.
As for where I'm at with the bike... flywheel is off, woodruff key is sheared. Off to eBay for NOS...


Great news - main problem found.... and a simple fix! You have a bike well worth keeping ……..KB

Well, we have a runner! Not without a fight or some bad news too but I still call it a win! First fearful moment...I have a dial indicator and buzz box that I consider indispensable for setting timing. The feeler post that senses the piston movement broke off while inside!! Good god my heart skipped a beat. I treat the tool like gold and always make sure that post is on tight, it must have been damaged to break off with the threads in the dial indicator but luckily the piston was high enough it wasn't hard to get out. Phew. So, there goes my timing device. A Yamaha guy I know said he had a woodruff key for me but I was leary cuz' I suspected it wasn't NOS but was willing to take the risk. Feel free to scold me. I couldn't set the timing properly so I adjusted the points the best I could and she ran. My idle jet is stripped so more work to do there. I called it a win and pulled the flywheel to see what the woodruff looked like. On it's way to shearing so I'm on the search for new old stock. Is there supposed to be a tab on the stator for helping with timing? I don't see one and am trying to do my best to time it without my proper tool.

Nothing was wrong with your dial indicator. Probe needs to be parallel to bore which on that model means you need to pull the head.

Nothing WAS wrong with it, until I broke the probe off like a dumbass. It read in thousandths anyway, time for a new one.

My comment was directed at your comment above... If you get a new tool and use it in a steeply angled plug hole, you will likely break the new tool. You need to remove the head if the plug hole and indicator mount does not allow the indicator probe extension to be parallel to the bore...

Central Tools makes a dial indicator kit that that has a fixture to allow the use with angled plugs holes... but it won't work with steeply angled holes and it takes a lot of space to use so doesn't always fit with the engine in the frame.

And you probably don't need a whole new tool... using something like a pencil eraser you should be able to unthread the broken threaded piece. McMaster-Carr and other tool places sell the dial indicator extensions in all kinds of lengths...

I've broken one off before too... Thought I could use geometry to compensate for the angled hole but ended up breaking the extension off.

Yes sir I got a case of the dumb as I was so excited about the potential for first start. Live and learn! I ordered the only 68-71 woodruff on eBay and then checked Babbitts and they also had it, different part number so more research needed
Probably just get that one too with some other items at Babbitts. Again is there supposed to be a timing tab on the stator?

Keys are available new from Yamaha. Very common part so as with many parts, likely number has been superseded.

Timing tab was never "endorsed" by Yamaha as a way to set timing. It does come in handy in a pinch though if you've verified it's correct with the dial indicator. I don't remember a model not having one though some are missing and many are bent to hell and therefore useless until you use a dial indicator.

If you don't have timing tab, you can make your own timing marks once you take off the head and use the dial indicator to get the piston in the right place BTDC.

Eraser trick, genious MarkT!

For the win!

you can make a dial indicator adapter using a head bolt from a DT1 or RT1 for your dial indicator.
here is some pics of my dial indicator adapter for Yamaha.


with the pieces needed it is not hard to make one of these.