I had my CS6-1 running today for the first time in a while. I was playing around and substituted the governor spring for a length of elastic bands and I was able to get the thing to run very slowly indeed - just fast enough to make it over compression.
I started to wonder if there was a speed achievable that would be too slow to throw oil onto the cylinder bore from the big end dipper. Is this a potential problem or need I not worry? I'll desist from further experimentation with slow running until the 'team' deliver their verdict!
I would be _very_ cautious at running an old engine much below its rated speed. There are just too many things that can get too little oil. It should not be very noisy running with no load, but if noise is a problem rather improve the silencing, possibly fit an air filter to cut induction noise, and fix the mechanical clatters if any.
A lot of the oily whirry bits rely on splash lubrication, not enough rpm means not enough splash- so I wouldn't recommend it. Also the engine won't ever really warm up- and the CS is a cold blooded beast anyway when off load. Oh, and for light load running leave it on the high compression setting.
I concur. The engine oiling in simple splash systems is arranged around the manufacturers recommended running speed. Much below that - or use of an oil of too thick a viscosity - & things get squeaky.
The Iron Horse (AKA BSA or Chore Horse) engine has a neat sort of semi-pumped system. The conn rod has no dipper, but the lower timing gear runs in the oil sump, hauling oil up between the gear teeth which then splashes into troughs which feed the flailing and whirling bits.
I remain impressed with these unassuming units. I have three, any one of which can be dragged blinking into the light & fired up at a few minutes notice. They will then run all day with no attention, are frugal and quiet and - unfortunately - are about as memorable as John Major.
Still cheap, though & I'd like to find a mains one sometime ..........
The CS has a simple plunger oil pump for the main bearings, which pumps oil into the galleries above the bearings and runs through.
The big end, small end and piston rely on splash as has already been posted, so I would concur with the others and say that it would not be good to run too slow.
Philip's comment re the cool running is another very good reason not to do it.
Peter
-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:
Right you are. I was really wondering if anyone had some practical experience here rather than conjecture and theory - I can manage those two myself! Has anyone ever had one tighten up or perhaps start squeeking as a result of it running much below it's design speed? I suppose the rally field is the best place to ask this question! I do run it at around design speed normally -I was just playing.
Talking design speed, have you seen the RPM that some of these Indian CS copies run up to? (about 1200 IIRC) You must need one hell of a block of concrete to keep it still. I wonder if the flywheels ever fragment?
It was a wierd experience starting it for the first time in a long while, having become used to starting my Field Marshall with it's fairly large cylinder recently, the CS cranked so easily that I felt the conrod had been removed!
I can get the cylinder and head hot, but not the oil. I once left it all afternoon running a 3kw fan heater (that made it produce a trace of black smoke) and the oil was really not much more than warm.
There are a number of plain bearings on the camshaft and idler gear which rely entirely on splash, the camshaft gear at the far end of the camshaft from the governor is pretty much dependent on removal of the OIL plug and a squirt of oil every now and then. The outboard bearing at the governor end is not lubricated at all by hand and so would probably be the first to run dry. Peter
-- Peter A Forbes Prepair Ltd, Luton, UK snipped-for-privacy@easynet.co.uk
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