HS50 is blowing oil

#1
I took my Hilltopper for a 5 mile ride today and when I drove home and parked the bike, I noticed that the engine breather is blowing more than what I would consider is normal.
Checking the oil level, the dip stick shows it has dropped down to the 1/2 full level.
The breather is intact and the filter is like new.
Since the engine was opened, I wanted to make sure the engine got well lubes. I'm running 5W30 oil for that reason.
Can the thinner oil be a cause of the oil leak?
The oil is clean and clear on the dip stick.
The oil that is blown out is black.
Any idea why the engine is blowing out so much oil?
 

pomfish

Well-Known Member
#2
Blowby
30w may help some but you may have rings not seating properly for whatever reason.
Is this the engine that had low compression?
5 Miles and half oil gone, I'd be concerned as well.
 
#4
Did you deglaze the cylinder before putting the rings back in? If not, the rings will take years to seat. It's the first few minutes of use against the honed surface that makes the rings cut in (seat)….during this brief time I like to ride it like I stole it so the rings get plenty of pressure to seat before the cylinder wall can become glazed. YMMV
 
#5
The engine only had three hours on it when I bought it. The engine was absolutely spotless on the inside with no wear other than a very slight scuffing of the bottom of the piston skirt ( see my photos) When I pulled the engine apart two weeks ago the cylinder bore still had all of it cross-pattern honing marks on the walls. Two of the piston rings were in alignment with each other which I corrected. The oil wiper ring was in the correct position.
The piston was a nice "tight" fit into the bore. The gap looked to be normal, I did not have a feeler gauge that would fit this engine to check the gap.
I will drain and refill with straight 30 weight oil and see if that helps.
 
#7
I changed the oil to straight 30 weight. I also installed a temp "catch can" onto the breather pipe.
I wanted to see how much oil would blow out on a "high" speed one mile trip.
From the looks of things, none. nary a drop of oil came out.
The rings on the piston may be seating properly. The bike seems to have a little more get-up-and-go and climbed my hill a littler better.
Still not the performance I need, but I'm making head way with this 5 HP engine.
catch can for oil.jpg
 
#8
After sitting for an hour,there was oil drips from the chain cover. I pulled if off and found the crank case seal was the culprit.It is original and even though I used cam lube when I put the side cover back on to protect the seal, it did not like the heat and the RPM's and started to leak. The oil slinger I put on the shaft threw the oil all through out the cover and onto the crank case breather tube. I misread the signs and thought it was the breather/blow-by.
Now that I have to pull the engine again, I need to rethink using this 5HP engine. I have a new Greyhound 212CC engine sitting on the shelf.
I would need to shoe-horn it into the bikes frame as the jack-shaft is in the way.
 
#9
Why not just replace the seal its pretty easy once clutch is off. The reed valve in the breather should keep negative pressure in the crankcase so that oil is not pushed out the seals, however if the seal is bad it certainly will cause a leak.
 

pomfish

Well-Known Member
#10
I pull side cases without removing engine.
Just loosen all the engine plate bolts some, then loosen the 2 closest to clutch a lot and insert a flat head screwdriver under that side of block from the front.
Now you have room to wiggle off the side case and don't have to remove throttle, etc.

If you want to use that Greyhound you could fab up a spacer plate to get clearance of jackshaft maybe?
Don't know what space you have to play with.
HTH
 
#13
Can't you just remove clutch, drill small holes in seal face 180 apart being careful not to go in more than 1/8 inch. Screw in two sheet metal screws about 1/8 " and pull out old seal.
 

markus

Well-Known Member
#16
I changed the oil to straight 30 weight. I also installed a temp "catch can" onto the breather pipe.
I wanted to see how much oil would blow out on a "high" speed one mile trip.
From the looks of things, none. nary a drop of oil came out.
The rings on the piston may be seating properly. The bike seems to have a little more get-up-and-go and climbed my hill a littler better.
Still not the performance I need, but I'm making head way with this 5 HP engine.
View attachment 261728
was your "catch can" vented? If not it was like plugging the hose and the crankcase pressure will have to find other spots to exit from.
 

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