Hello all,
    I picked this up at a yard sale. I cannot figure out the year/model. It is from the 1970's I am pretty sure. But what model? The angled rear shocks are messing with me! Can anyone identify it? Not rare I am sure, but cannot figure it out!

Jeff  

Just get the VIN number off the steering head and engine.

If I had to guess... it would be a 1974 MX125 that someone has (rather professionally it looks like) done a "lay down" mod to the rear shocks... modifications like that were all the rage back then.

Looks like the original upper shock mount is still there near the rear of the seat.

Thank you!

Circled in red is where the original mount is for the rear shock.

 

Welcome. If ya gonna start it i'd premix some fuel looking at the oil pump cable hanging there. Oil tank may not be on it anyway as the shock mod frame stay might meant oil tank needed to be removed. Pump might be blocked off or removed. Good luck & video would be great when she runs. You guys are So Lucky, nothing like that left where i am in NZ, or if there is its well hidden.

What mix ratio would you recommend?

Good question & i seem to run my bikes hard so run 20/1. But i'd use 30/1, you'll be good. I can't offer advice on oil type as not sure what's available in the US. Just a regular known brand 2stroke oil. Not worth going expensive synthetic stuff at the moment. In my opinion.

It does depend somewhat on oil and how you intend to ride... I'd also use 20:1 and a good "old fashioned" oil... even WalMart SuperTech 2 stroke is cheap and works great. Much better quality than oil that was available when these bikes were new.

Putting around, 32:1 would probably be ok... I like to feed these engines... especially the high performance ones like yours... lots of oil. (Pretty sure Yamaha would have recommended 16:1 with autolube removed.)

You also can't go wrong with yamalube oil... kind of pricey these days.

Thanks. Any advice on removing the injector? My plan was to take it out and cover the hole with a plate and some gasket material. Then plug the other end where the line runs. Any advice?
Jeff