idle curiousity - trying to find what model my father had for 2 stroke yamaha 500

[wymple]

It wasn't that uncommon for guys raised on 2 strokes to add a touch of oil to their 1st forays into 4 strokes. We called it wet engines, the idea being longer engine life. I say he did this with a TX500 Yamaha, or really just had a Suzuki Titan twin.

[seanarthurmachado]

I think I mis-spoke, dads bike needed carburetors synched not valves adjusted.

I wish I could remember the letters in front of the 500 on the side covers.

The rd350 looks a perfect match but wrong size e
ngine. But I think almost all the bikes would be real similar from then.

[GS1150Pilot]

There were no 500cc 2-strokes from Yamaha at that time. Hell, even the YZ465 was years away.

[GS1150Pilot]

An RD250 for reference ...

[seanarthurmachado]

I would say tx500 spot on. On a look the rd doesn't seem right. I remember it having a round key, a gas tank cap on a hinge that locked. Shiney chrome engine that filled the whole space. Either no clutch lockout for ignition or was disabled. (When i was 5 he left the bike outside with key in ignition. I knew to turn the key on and press the ignition button to start it. I remember monkeying with the gear shifter, then starting the bike from the far side since I couldn't reach the button on the right side and the bike taking off and falling over.)

The Kill switch might have been a red turn to kill not a toggle switch. The Cluster may have stated "unleaded only" but I am unclear if this was the original gauge since he replaced the gauge at one time. I do remember him telling me the bike needed 20:1 of oil when I asked why he put oil on at fill up. (Same conversation when he told me he disabled the auto oiler.)

[GS1150Pilot]

It had to be either an RD350/400 or one of the TX/XS bikes.

[bwringer]

I'm pretty sure the RD350 didn't have electric start. The OP clearly describes pushing a starter button which dumped the bike (not sure of the TX500's exact arrangement, but most bikes of the era did not have a neutral starter lockout), so I think we can rule out the RD.

As we've said before, it was very, very common in the '70s for people to mix oil in the gas on bikes with 4-cycle engines, so it's hard to take that as much evidence one way or another.

You still see this strange belief pop up today -- there's a thread over on the V-Strom forum right now where some geezer is advocating oil in the gas as a cure for everything from spinal curvature to ho-hum breath.

[seanarthurmachado]

My eyes tell me the tx500 could have been it. But since the tx was a 4 stroke and would not have had the auto oiler that dad said he disabled for unknown reasons who knows. I've been searching to see if there is a way to check his registration records but I don't see anything online. Probably too old to be put online.

[Cyrano]

I'm pretty sure the RD350 didn't have electric start.

But the early '70s models like the CS5e (200cc) and the YDS7 (250cc) did.

Keep going people, we'll get it in the end.

[8ball]

Are you sure it was that he didn't trust the "auto lube pump" or he didn't trust the new unleaded fuel? There were more than a few people that added Marvel Mystery oil, or outboard oil to their gas to "lubricate their valves" because they didn't trust the unleaded gas in their motors. As a matter of fact, I read some guys post on an RV forum, recently, that says he still does it on his old RV!

[tkent02]

I can't think of any twin two stroke street bikes from the 70s with electric start.

[Cyrano]

I can't think of any twin two stroke street bikes from the 70s with electric start.

An example of one I mentioned earlier. I had one when I was seventeen.

[seanarthurmachado]

Are you sure it was that he didn't trust the "auto lube pump" or he didn't trust the new unleaded fuel? There were more than a few people that added Marvel Mystery oil, or outboard oil to their gas to "lubricate their valves" because they didn't trust the unleaded gas in their motors. As a matter of fact, I read some guys post on an RV forum, recently, that says he still does it on his old RV!

I don't think it was marvel mystery oil due to him telling it needed 20:1 ratio and rattling off some massively quick math off the top of his head about some amount of gallons and fraction of gallons to ounces needed while pouring in the oil to the gas tank.

I remember a conversation about leaded vs unleaded gas

He also constantly ranted about Harley Davidson bikes being unreliable, I remember him stating that him and the club went for a ride, 2 members had brand new Harley Davidson bikes and at a fuelstop just after first service died. ( he also complained that he would stop for gas with them and by the time they were done kickstarting he needed more gas