engine blow-by questions

[dolt]

The last pressure test was with the damaged carb seal in. did again with the new s&s seals and all is good. Been getting it out a little the past few days trying to get some breakin miles on it. Runs and sounds great. Had another thing I intended to work on after the engine, an oil leak under tranny. At first thought it was from oil drain plug because I had over-tightened it last time I changed oil, but on closer look found it was coming from a bolt on corner of oil pan that was loose. tightened it and one next to it that wasn't tight. leak still there. Well, first couple days of riding the leak almost disappeared, then came back a couple days ago. Checked oil level this morn and it showed at full hot level on stick. started bike rode it into the garage. shut it off and checked, back to full cold.

Good news on the top end. Are you sure the oil leak is motor oil? Sounds to me like the primary or transmission could be the source of the leak. Get the underside of the trans, pan and primary really clean and dry to try and locate the source.

 

[Jeff Klarich]

Leaks can be a real pain and the source can be deceiving. The'll take the path of least resistance and gravity will bring it to it's lowest point before it drips. Do as dolt suggested, cleaning the bottom and recheck. Finding out what the fluid is would be most helpful when looking for the culprit.

 

[Jack Klarich]

If you are not sure, try this you can find it @ Graingers, Auto Zone and others:Add a bit to your oil to be sure it is not the leak

 

[mystryman]

I had this leak before the engine problem. had plans to work on it in near future. I had took to the wash and soaked everything with degreaser then washed it. took it back home and looked it over with an inspection camera ,( one of those things with a cam and a light on the end of a flextube, much handier than a mirror on a stick). that was how I found it was originating from a bolt on a corner of the pan. What puzzles me right now is how the oil was all the way up to the 3rd mark and then went back to the second mark after it had been started.

 

[Jeff Klarich]

Did it have time to drain down and settle?

 

[mystryman]

Did it have time to drain down and settle?

When the level showed high? Yes, overnight. When I moved it from in front yard to garage, I checked it when I shut it off (let it run for a few to warm up), again an hr later and one more time 3hrs later. Seems it must have happened after taking a ride the day earlier.

 

[Rollbar]

Question, do you think the carb seal was the culprit the whole time and not needing pistons/rings?

Thanks,
Jim

P.S. Glad you have it fixed.

 

[mystryman]

Question, do you think the carb seal was the culprit the whole time and not needing pistons/rings?

Thanks,
Jim

P.S. Glad you have it fixed.

During the teardown I struggled to get the intake off because of a seized flange bolt on one head, leaving the flange still on the head. putting the intake back in I had to force and wiggle the intake back in and wound up slicing a chunk out of the seal on the other flange. seal was intact when I first removed the intake.

When I took the jugs and pistons to the shop, he looked at the pistons and pointed out the compression ring groove on piston from weak cyl. It almost had enough gap to install another ring on top of the old one. it definitely needed at least piston and rings in that cyl.

 

[Rollbar]

Ok thanks for the clarification.

 

[mystryman]

I've ridden the bike a few more times and the high oil level hasn't recurred. I guess for now I'll just treat it as a fluke. Best I can guess is when it was shut off the breather gear stopped at position that allowed case to maintain pressure and push some oil back into the tank. a wild guess, but only one I could think of that adds up.....lol.