I am still at the same point ... investigate a bit more to figure out what to do.

Send a borescope down the spark plug hole and do a leak down test 0.5-1.5 hrs of labor. [I would just purchase a cheap borescope ... it will pay for it self]

Also "next year?" 2027 or Chinese New year?

Salim

Bought myself a borescope camera. The cylinder walls look good. In great shape. That is a big relief. The valves look, well, they need cleaning. I couldn't tell that much by looking at them.
I'm going with plan B. That is I dumped a bottle of Risoline in the engine to help clean things up. Who knows, it could work.
No water in the oil. No smoke of any color out the tail pipe.
Gotta get some miles on it.

Did you dump the Rislone in the oil? It is basically kerosene and it will break up any sludge in your engine and put it in the oil pan and also it will clog up your oil screen and could mechanically damage your engine. A lot of people have found that out the hard way.

I did dump it in the oil. I know what it's job is and I didn't plan on leaving it in that long anyways. I was thinking 500 miles should do it.

I would run it for 15 minutes at idle and I would drain it all out. The problem is when you drain it out, you will still have sludge in the bottom of your pan and then when you put new oil in it will start sucking that up into the screen and plugging your oil pick up.

15 minutes, really? That doesn't seem like that's enough time to do anything. Is it really that much of a cleaning agent?

It is kerosene. Basically diesel. You could use it as a parts washer. Do what you want. If your engine doesn't have that much sludge inside, then you may be okay.

I'm not arguing with you, just wondering about when to take it out now. The oil was very clean on the dip stick before I added it. That might be a good thing.

I am wondering if your engine had a blown head gasket at one time and antifreeze or water got into that cylinder and hydro locked it and bent the connecting rod. They may have put a new head gasket on it and it runs fine but that bent connecting rod can cause all of your symptoms that you are having.

That's a scary thought.

But, it's not the worst thing that could happen. If you are mechanically inclined and since it is on the front head, you could pull the front head and pull the oil pan and replace that connecting rod and put everything back together. You would want to weigh your old connecting rod and your new one and make sure they are the same weight before you do so. Some metal may have to be removed from the new one.



by the way, I am an engine builder and both of my RX300s have engines in them that were built by me with new pistons and everything. I have run into many issues over the years on engines from several manufacturers, and I really think yours might be a bent connecting rod.

I have mixed opinion regarding additives and cleaners. If it is a good product it can give you a marginal improvement, but I seriously doubt that it can take compression from 40psi to close to 190.

My next step would be a leak down test. Air compressor, leak down valve-gauge assembly and time to set each cylinder to TDC compression stroke.

Salim

That is step #2.
I did get a leak down gauge set. It was just too cold to get it done yesterday.