Oil pressure issue / motor rebuild

[K2-K6]

Yes you're right Trigger,  I was just thinking of some easily accessible bare metal that you can easily get a big crunchy old jump clip onto without scratching the engine paint.
It's something I use on old landrovers as the quickest way to verify the earth.

[MrDavo]

I see the point, but it doesn't make a difference. I tried a jump lead from the negative terminal to the kickstart, but I'd already measured zero resistance between -ve terminal and the engine so it's not that. After an initial struggle it turns quite well, but that first moment is horrible.

I'll try a car battery tomorrow, if it's ok I'll order a solid state modern one, either to rule it out or make it maintenance free, as I recall old technology lead acid batteries often died when they got cold and flat.

[hairygit]

It's a possibility that the previous owner and yourself between you have knackered the starter motor brushes, replacing them is cheaper than a new battery, and provided you clean out/undercut the mica segments in the commutator it should be fine again for many years.

[MrDavo]

Worth checking, do I need to take the alternator cover off, I reckon not?

[hairygit]

No, just the chrome cover on top of the engine behind the barrels, no oil to spill

[MrDavo]

Its off and apart, what do you think of this on a scale of 0 to banjaxed?

Pretty damned filthy, I don't know if that's my problem totally, but it can't help. I'll sort this before trying a new battery or 10/40.

I'll order new brushes tomorrow, DS has the genuine article in stock.

[Trigger]

That needs a good clean. Use WD40 and scrape all the grooves on the copper with a tooth pick.

[Bryanj]

Orrible with a capital O, best cleaner is Armaclean but not that easy to get

[K2-K6]

That's probably the PO turning it over with those tight main bearings as it ground lumps off them does look pretty mucky.

Looking at oil temp range in Honda manual, and it says 20/50 ok down to zero degrees. 10w just extends usable operating range lower to -15c so I can't see it would affect it. It may be at ambient temp now that the two are all but identical in practice.

I know Bitsa always advocated 20/50 for these and I've always used it without any problems partly because of the top temp range is useful if it's running hot. Queing in and out of road race bike meetings always got mine stinking hot.

[AshimotoK0]

If you look in the Honda manuals in My Drop-box Dave there are refurb detail in there. It may be better in the CB350 twins manual than the 750 one .. not sure & I can't check for you at the 'mo. All of the Mutsuba starters  have armatures/commutators/brush arrangement which  are basically the same, it's the gearing & wattage that differs.

[MrDavo]

Right, cancel the gel battery and the thinner oil, the starter refurb was a 100% success! No pics yet but the +ve brush was 1/4 inch long, the service limit is 1/2 inch. I doubt the spring was even working.

Yet again you guys made me spend £12 and saved me £100.

The motor whizzes round, the oil light goes out after a few seconds, and I can now confidently report to Trigger that there is oil upstairs in the cam box that I didn't put there.

[Nurse Julie]

👏👏👏 Well done Dave, I bet there was a huge sigh of relief when it all worked as it should do

[JamesH]

Awesome well done Dave...!

[hairygit]

It's one thing people often overlook, I would guess that 90% of bikes our age have never had anything done to the starter motor bar removal and refit for engine rebuilds, and most are more than 40 years old, and people seem surprised that they fail due to worn brushes! Still, glad you got it sorted, next is to get it running! 

[Trigger]

Hairy, see all problems are down to electrics on these old girls