1974 Norton 850 Commando Starting Problem

A reader’s 1974 Norton 850 Commando has been harder to kick over ever since a new reed valve was installed on the breather hose.

Reader Contribution by Pete Morland
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by Keith Fellenstein

Editor’s note: If you’re having trouble with that old Suzuki, BSA or BMW, Keith Fellenstein is your guy. From motorcycle tuning tips to detailed motorcycle engine repair, he can draw from a wealth of experience to help guide you to success. Send questions to: Keith’s Garage, Motorcycle Classics, 1503 SW 42nd St., Topeka, KS 66609, or send an e-mail with “Keith’s Garage” as the subject.

Q: After letting my 1974 Norton 850 Commando sit for around four years I began to fit some new parts and upgrades. Among them is a Yamaha 650 reed valve which has been installed on the breather hose which exits at the right rear area of the engine. The bike now seems harder to kick over than it did a few years ago. Could this be caused by the valve? I also replaced the oil seal on the left side of the crankcase which required the removal of the primary but it seems doubtful that this could be the cause of the starting problem. It is as if the bike has more compression than before. Thanks.

— Pete Morland/via email

A: The only way I can think that valve would make starting more difficult would be if it was installed backwards. Remove it and blow through the valve. One way will let air through and the other won’t. We’ll call the one that does the inlet. Install the inlet to the timing chest at the right rear of the engine.

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