New (to me!) '77 CB400F - US model

[mattsz]

I guess I need to brush up on the firing order and workings of this engine.  Is there a crank position where all the valves are closed?  I'd like to leave the engine in that condition, if possible, when I put it to bed for the winter...

[hairygit]

Short answer, no! The only way to get all valves closed is lift the rocker cover, but probably not a good idea.

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[taysidedragon]

Short answer, no! The only way to get all valves closed is lift the rocker cover, but probably not a good idea.

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Or slacken off all the tappets so they are not pushing down on the valves.
Have to do that before taking off the cam cover anyway. 🔧👍

[ted_paper]

Hi,
I have Kevin's phenolic brake piston fitted for the last seven years and have had no problems with sticking or anything else.

[mattsz]

I had a few minutes to kill this morning...

Battery: I topped up the cells with distilled water, then left it overnight on my 0.75 amp tender; it reached about 6V (it's not meant to charge a dead battery anyway).  Over the next couple of days, I managed to get it charged to about 13V using a bigger car charger (set on 2A) followed by a topping up with the 0.75A tender.  But when I reconnected it and turned the key, I got nothing.  I connected a volt meter, with the key off it read about 10V, but as soon as I turned the key, volts dropped literally to zero, so I'd say the battery is shot.

I removed the plugs - last run two years ago:

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The oil on the dipstick looks very clean and clear.  The kick start lever easily turned the engine over, by hand.  I added a teaspoon or so of oil to each cylinder, turned the engine over by hand a few times, then I figured I'd try to check the oil pressure by spinning the engine.  I hooked up a spare battery pack... remember three years ago the PO said the starter didn't work when it was wet?  Well, it's not wet now, but it still doesn't work.  The start relay buzzes loudly, though, so I'm thinking that should be a simple fix.  The starter button feels kind of sticky anyway, so I'm just as happy not to try to use it and have it stick on with the starter turning.  No big surprises or concerns there.

I kicked the engine over manually, still without the plugs in, key on and powered up - after about 20 kicks, the oil pressure light went out, and stayed out for about 20 seconds.  After it came back on, one or two more kicks turned it off again for a few seconds.  10 or so kicks turns the light off for about 20 seconds.  Does this seem like a reasonable non-running oil pressure test?

When I change the oil again before storage, is it enough to try to circulate it manually, or should I see about bypassing the starter relay to properly crank the engine?

[mattsz]

Hi,
I have Kevin's phenolic brake piston fitted for the last seven years and have had no problems with sticking or anything else.

Thanks for that info!  But as near as I can tell, Kevin is not in the USA and is no longer supplying parts...

[Bryanj]

Oil pressure sounds good, if the oil looks clean and does not smell of petrol i would leave it in there till next year when you are ready to get it going again.

[mattsz]

Oil pressure sounds good, if the oil looks clean and does not smell of petrol i would leave it in there till next year when you are ready to get it going again.

Thanks!  I was thinking of changing the oil as cheap insurance, since I don't know how many miles or how much time went by on the current oil before the bike was stored for two years.  I'll sniff around for fuel in the oil...

[Nurse Julie]

If oil does not smell of fuel, i would also leave what's in there over winter. If you are not running the engine, the oil isn't going to break down, it's just coating all the surfaces. Plugs look fine.

[mattsz]

So no worries about moisture or acids in dirty oil to contaminate or oxidize engine internals?

[Nurse Julie]

Air, not oil or water causes oxidation. As long as the oil is all around the engine internals, it will do more good than harm, regardless of the state of the oil.

[mattsz]

Huh.  Every resource I find concerning storage preparation suggests changing the oil before storage to avoid corrosive damage from oil-borne acids and carbon deposits.

I thought a few new quarts of oil would be smart, due to the unknown condition and age of the current oil.  But maybe there's no point if the only way to properly circulate it is to run the engine?

[Nurse Julie]

I must admit i have never done any research of what process to carry out to store a bike. It is such a short term storage,  taking the bike off the road for the winter, i don't even consider it to be storage really. I have a bike here of my own, a CB750/4, that has not been in the road for 3 years, i didn't change the oil or do anything else. Everything will be checked, changed and serviced before going on the road. No point in doing it before a few weeks lay up and again after.

[mattsz]

All good Julie!  This one will be sitting for six months, and with so many unknowns, and my lack of experience with these things, I've been making my plans on the side of caution...

[Nurse Julie]

Understand Matt 👍. All our old Hondas that we ride came off the road last week and will not be ridden until April next year at the earliest and they were just parked up with no prep. I worry a lot more about rust forming on chrome parts than anything to do with engine internals.