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Crankcase blowby
- cbclemmens
- Posts: 220
- Joined: Sun Apr 25, 2021 2:21 pm
- Location: Apollo, PA
- Been thanked: 5 times
Re: Crankcase blowby
As I said my compression dropped from 160 pi. to 100 psi. rather quickly and in both cylinders. I took apart and cleaned the crankcase vent. When I did the spring flew off and brushed my forehead as it flew away. I scoured the floor and bike surfaces to no avail. I ordered one from Max, only $2.00 but it has to come from Germany. I went back out to the garage and moved everything in the area (3 bikes, 2 lawn mowers, etc). Then I swept the floor and dragged a magnet through the pile of dust. I found the missing spring clinging to the side of the magnet.
That crankcase vent is so simple I don't see how it can be the problem, as long as it is clean. I blew air into it and the air came out the dipstick hole. When I reassemble, I will blow air in the dipstick hole and see if it comes out the vent.
Craig
- srankin
- Posts: 1078
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- Location: Spencerport, NY USA
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Re: Crankcase blowby
A bad habit of mine is to read these posts first thing in the morning before I have had a couple of cups of coffee and am fully awake. I apologize.
That big a drop in compression in my mind screams something major changed. You are on the right track getting the problem solved. LOL, I will keep an eye on your progress but keep my fingers off the keyboard for replies until I am sure I have read what has been posted. Cheers, St.
- cbclemmens
- Posts: 220
- Joined: Sun Apr 25, 2021 2:21 pm
- Location: Apollo, PA
- Been thanked: 5 times
Re: Crankcase blowby
I'll be down for a couple of days, but I'll post my progress when I get back to it.
Craig
Re: Crankcase blowby
While the jug is on the bench you can push out the piston and fuss with the rings. Then it's easier to use a regular ring compressor to put the pistons back into the jugs. Some guys just use their finger strength to compress the rings one at a time.There is a chamfer on the jug.
-Randy
- drpetemurray
- Posts: 80
- Joined: Fri Feb 06, 2015 5:13 pm
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Re: Crankcase blowby
Stroudsburg,Pa
73 R75/5 , 1014 RTW, IBA 359
- cbclemmens
- Posts: 220
- Joined: Sun Apr 25, 2021 2:21 pm
- Location: Apollo, PA
- Been thanked: 5 times
Re: Crankcase blowby
I did not disassemble the valves. If you read back a couple of posts you will see that I filled the inverted heads with 1k and they didn't leak any out, so I didn't see the need. The rings slid back into the jugs very smoothly with my makeshift compressor so I think I'm ok.
I had to have a minor medical procedure Friday and so haven't finished reassembly yet. I got the jugs back on and let it sit until I could get back to it.
Craig
- drpetemurray
- Posts: 80
- Joined: Fri Feb 06, 2015 5:13 pm
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Re: Crankcase blowby
I wish you and your motor good Health.
Stroudsburg,Pa
73 R75/5 , 1014 RTW, IBA 359
- cbclemmens
- Posts: 220
- Joined: Sun Apr 25, 2021 2:21 pm
- Location: Apollo, PA
- Been thanked: 5 times
Re: Crankcase blowby
300 miles and no sign of leaking so far. (The orange color at the base of the jugs is Permatex high temperature RTV gasket sealer.)
Craig