The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: joecr on 18.03. 2008 15:02
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I'm about to do a compression test on my A10 plunger, can anyone give me a round about figure for what the reading should be on a healthy engine? I've only had the bike a short time and the last owner put new pistons and rings in and it hasn't been run in yet. I would like to check periodicly to see how the rings are bedding in.
Thanks, Joe.
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Joe,
Go to topic "Measuring Compression" (pg. 4 under "Tech Topics") and you will get a whole lot of discussion on the topic.
Richard
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Oops, should have looked before I leaped, everything is there that I wanted to know.
Thanks, Joe.
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after checking mine , its been standing for some time compression down to 80 or so to it's head a barrel off tomorrow and have a look
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ring gap on compression ring 25
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That's not too bad Nick. I've seen them running well with gaps bigger than that. Were you holding the throttle wide open when kicking over and at least 6 kicks?
My low comp '51 A7 shows 130 Lb sq in, the high comp A10 shows 175.
Cheers
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thanks , i also check it out with my friend gary at srm but when i pour petrol down the exhaust port it is seaping past so grid the valves in again the next stop. the only fun i had was getting the 2 bolts out at the front holding the head down . i did not replace them last time and the head are getting a bit round and all that heat a bit firmly fixed in place but with a bit of penetrating oil they came out