Hello I'm Steve - I've got a 750 Mk4 Commando that to be honest I've never had running properly. It runs on one cylinder, sputters on the other, ocassionally fires on both. Wet sumps and chucks lots of oil out of the timing side breather hose onto my leg. It's fitted with a Lucas Rita ignition which sparks both plugs when tested by placing them on the head.
It has been suggested that my oil pump may not be returning oil. Can anybody help? I really would like to ride it this summer. I'm in London/Kent borders.
Thanks
Steve
Hi Steve, A few things to…
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Thanks for the reply Ian .…
Thanks for the reply Ian .Ive been working so have only just read this .Ill go and get some new plugs yes the old ones were properly gapped.The inlet manifolds will be checked .I wont be fitting a tap to the oil line too risky .Right the sad bit I,ve owned this bike for 20 years and it never been on the road ,occasoinally I start it with varying degrees of success from running on both cylinders to one .And now its started to chuck considerable amounts of oil out of the breather on the top of the timing side case.Ive checked the rita ignition which seems ok swopped the coils over no differance.Ill do what you recommend,then refill it with fresh oil ,new plugs charge the battery and see if it runs thanks
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Hi Steve,
A few things to check for you:
I know you say you can see a spark at both plugs when they are grounded on the cylinder head fins but they are new plugs and correctly gapped.
Do have a good look at the carb inlet stubbs for air leaks. Make sure that the manifolds are perfactly flat and do not over tighten them.
As for the wet sumping: they all do that to some extent. How long after it has been run does it wet sump. If it happens quickly then consider taking the oil pump out and checking/refurbishing it. Be very, very, VERY, careful if you put a tap into the oil circuit. The consequences of the time when you forget to turn it on are dire! If the pump is worn then the main problem is not the wet sumping but the fact that it means that the rockers and the top end of the engine may not be getting an adequate oil supply.
Ian