The spring that controls the timing advance on my RT1 is loose and does not seem to really do much.  I was looking to replace it but don't see it on the parts list.  Any ideas?????  Thanks in advance!

Hard to know if what you're describing is normal because a word like "loose" or a phrase like "doesn't seem to do much" could be describing the normal condition of the advance mechanism or it could be a problem. 

Just know the "advance" is only there to ease starting.  Once it starts should be at full advance, even at idle speed (or maybe a few rpm above idle) 
 

Thanks, Mark.  I appreciate the response.  The spring, though weak, retards the timing.  So, I guess that jives with your comments about only being there for starting.  To be honest, I tried it without the spring and it did not seem to make any difference in starting or running.  Still curious why it does not show on the parts diagram?

It's part of the flywheel assembly.  There's several "assemblies" on bikes and cars that they really don't break down and sell all the parts individually.  Worse today than it used to be.

When I was a kid I remember going to an Auto Parts store with my uncle Jack...  he was pissed off because he wanted to buy a water pump kit and all they had was a new or rebuilt pump assembly.  We drove to several stores until we found one that sold a kit...  and then he spent the afternoon working on the car and showing me how easy it was to rebuild a pump...  it literally only took a few minutes and the kit was about 1/3rd the price of a pump.

Hey guys, I am going to revive this thread because my bike is still running like crap.  It has new piston and ring and fresh rebore.  It has new points, the exhaust pipe has been burned out and the carb has been cleaned 51 times.  It stubbles and sputters and will not rev above 5500 RPM.  

There is not much left and my mind keeps returning to the timing.  When I apply a timing light at idle, it is exactly correct.  When I rev the engine, it never moves.  I can appreciate what Mark is saying above, but it just doesn't seem right that there would be no timing advance as the engine revs.  How can the timing be the same for idle and for 6000 RPM?  Does anyone have any thoughts on this???????

What air filter do you have? I have 2 RT1Bs. One is a garage queen. On my regular rider I found that a modern oiled foam filter was too restrictive. (New air filters for these are not available from Yamaha). I installed an RT3 airbox and Yamaha OEM filter with a modified lid to clear the seat. I don't oil my air filters since I only ride on the street. Also installed a new repop air boot. Runs much better.

Also what main jet do you have? Mine is a # 260.

Also the spring on my flywheel is not loose.

My spring is tight too.

My spring has no slack.

You say timing doesn't move but if its the advance flywheel when its running its probably already advanced. On mine i could hear it retard 'Just' before it stopped for a couple of beats. Think that was more because it had low compression & it would run very slow until it stopped. Each case is different slightly due to spring wear & wear of where the spring hooks on plus where the arm moves in the cam. So if yours strobes to 2.9btdc or whatever, then should be good. If jetting is std & air filter not restricted & also the little Oring is sealing--then hate to say it but exhaust is still top of my list especially if it stumbles getting to where it limits its revs. But--If it 'does' have full power but goes rich instantly at revs--say 5500rpm then i'd think way too big main jet.

Two stroke is a different animal and due to turbulence and other factors they generally require less advance as RPM increases... which is exactly what modern two stroke ignitions do, they retard the timing at high RPM. 

They work great with fixed timing though.  Millions of them out there to prove it.