RZ/RD 350 & Misc. 2-Stroke Tech BBS

I've been tearing down my first RZ, bought it in non-running condition... so a gamble here. In any case I was going through it and went to drain the oil. I was expecting a gush of oil to come out but instead what I see looks like grease as far as viscosity goes. Definitely not 10-30... The bike was stored with the fuel petcock on pri, I understand that allows gas to get into the oil, but I don't think that would cause the oil to become super thick, if anything it would thin it out? Maybe someone was hiding bigger problems? But why put grease in there?

The 2-stroke RZ engine is generally very similar to your 2-stroke MX bikes.
The crank is separated from the gearcase so gas from the carbs should not enter the gearbox.
If the float height is wrong, gasoline can flow into the cylinders and fill the crank but it should not get into the gearcase unless you have a bad right side crank seal.
If a waterpump seal goes bad, you can get water/antifreexe in the gearcase.

I don't have a good guess on what would make gear oil turn to a paste like that.
In any case, most of the people here will tell you that the first thing you should do is yank the carbs and make sure they are clean and jetted correctly.
With a bike this age, if you don't know when the crank seals were last replaced, you should do a leak-down test.
If the leak down shows a bad crank seal, you will be splitting the cases anyway and can clean the goo.

The down and dirty fix would be to flush the gear case with an oil solvent. Then use Bel-Ray Gear Saver 80w or similar.

Thanx brrrappp, I'll go down that solvent, gear save, leak down test road. Is pretty weird.

https://www.youtube.com/watch?v=MskJaTr ... l=ViralHog

If it's anything like this inside I would not take shortcuts. Just split the cases and clean it all out properly. Throw in some new crank seals and put it back together. You will be a lot happier with a job done properly.

Don't know what caused this but it looks like someone mixed oils, or even worse thought the oil filler cap was for anti-freeze. With humans it could be anything! A friend of mine gave my a fairly new RZ bottom end that the crank was rusted totally solid. Apparently the owner had put the bike away for the winter without draining the carbs or even considering gas stabilizer. What's that? Next spring it wouldn't run right. Someone told him the carbs needed cleaning, so his solution was to fill the tank with water and kick it through the engine. That's the way he left it. Rotted out the gas tank completely. I had to torch the flywheel off the crank to get it off so I could split the cases. Motor was like new inside except for the crank which was totally rusted solid. Yes, an adult made these decisions!

Lare reply, I've been in hospital. Old bike so I'd beware and do the job properly so you don't trash parts unnecessarily. Easy job once you get into it.

My old RZ mixed 2 stoke from the oil pump I to the cases. Was just a seal that moved sideways. Starved the right cylinder of oil.