My RT's:
1970 RT1M
1971 RT1 Enduro
1972 RT1 Enduro with '72 RT2MX engine, so irrelevant
1973 RT1 Enduro

The questions:  I bought an NOS RT1 flywheel off E Bay several years ago but it's turned up missing somehow.  The original flywheel on the M engine when I bought it had the advance mechanism removed and the flywheel blocked at full advance, so the reason for sourcing the E Bay one.  My '71 RT1 Enduro has the stock flywheel with the advance mechanism intact.  My '74 RT1 has the flywheel with the advance mechanism intact.  I didn't buy any of these bikes new, so don't know what's been changed over the years.

There are about a half dozen flywheels on E Bay listed for RT1's & 2's and non have provision for the advance mechanism.  All of these show as correct for both 250's and 360's.  The Partzilla breakdown on the internet shows 250 and 360 flywheels as the same part number.  My service manual shows the flywheel as having the advance mechanism.  Has my mind gone Biden on my or are all of these flywheels SUPPOSED TO HAVE the timing advace type flywheel?

NOTE:  Edited t change the year model of the last bike in the list.

I know very little about the 360's compared to many on here...  I do believe only the first year or so had the advance mechanism to aid starting?  The ones without the compression release if I remember correctly.  Not sure why they stopped it because it seems the retard for starting was a great idea. 

In 1974 it was a DT360 which was a completely redesigned bike with a CDI and different cases that the earlier flywheels were too big to fit in without machine work.  So you might be mistaken on that year or someone has modified it to take points.

Could also be that DMV paperwork lists the wrong year...  some states used "year first sold" as the model year back then.

Thanks for the reply.  Actually I mis-typed the model years and didn't catch it until I read your response.  I don't own a '74.  I've got a '72 with a '72 360MX engine and a '73 RT1 Enduro in addition to the '70M and '71 Enduro.  The only bike I've got with the new style frame and bottom end is a '75 DT250.  My other 250's are '73 and older except for a pair of '75 YZ250B projects.

Back to the topic, my '70 RT1M doesn't have a compression release, nor a drilled hole in the jug for it,  but the '71 and '73 both do.  All 3 of these have the advance mechanism in the flywheel but outside of my '70 service manual I can't find anything else in print, at least on the internet, that shows it.  

My 73 RT3 360 does not have that mechanism, i cant say about the other years but im willing to bet that the 72 year isnt supposed to either but im not the biggest expert here.
On a side note if you dont have a decompression hole from the factory there is an adapter you can screw into the 2nd spark plug hole. I currently have this set up and she will fire right up with no kick back however as Mark knows im working out my carb issues right now. Hope this helps.

My piston port 360 had the advance flywheel plus the decomp. Was pretty worn out in the cylinder with low comp & could just about start it by hand without fear of kickback. Good system but mine could've had a mix n match of bits before i got it. Was just a motor complete i got with other reed valve "72 model parts. Did love that motor though. You can tell that flywheel by the way it steps out. & the stator plate has the points set out further from the crank due to the fat cam. 

I did some more research and it appears the piston port 1970 RT1 and 1971 RT1b had the advance mechanism to aid starting.

The reed valve 1972 RT2 and 1973 RT3 did not have the advance as far as I can tell.

Note that Yamaha used the "RT1" prefix in the VIN for all the above models...  you have to look at the complete VIN and compare it to the VIN tables to see the exact model..

Compression release did not come on MX models or the 1970 RT1.  Post in this thread confirms the 1970 did not come with decompressor (and is probably where I got the impression the RT1b didn't have the advance...  other info definitely shows RT1b with advance but not RT2/RT3)

yamaha-enduros.com/index.php/forums/gene...newb?start=10#126188

Lots of great replies and helpful information here.  Thanks guys.

Yep, none of the reed models had 'that' system. Would have helped if they did though as kicked back harder than piston port i recon--but maybe not. Must've ditched the idea as too many moving parts to wear out--as in the 175 of "74 if i remember right.

The main thing to keep in mind is that the 'advance' flywheel must be mated with the 'advance' stator plate.
Points are further away from the center line of the crank.

Non-advance flywheel mates with the non-advance stator plate.

 

Thanks Deet.  The '70 RT1M project has what I believe is the original flywheel and stator.  Somebody defeated the advance in the flywheel.  Like I said above, I bought an NOS one off E Bay several years ago.......... about the time I bought some special tools for the cases from you.............. and now I can't find the damn thing, so went lookin' on E Bay and Partzilla and got all confused and started questioning my memory.  There are currently 6 RT1 flywheels on E Bay and none have the mechanism although some of them show as pre '72 and even the Partzilla breakdowns for pre '72 which I assume come from Yamaha show the same part number for DT and RT on the early ones.  But anyway, now that it's cleared up I'll keep huntin' my new one and searching E Bay in the mean time.