Topic: CB750 Oil Pressure - Got oil pressure gauge now title amended

[dave500]

when chicks see me they lay eggs!

[kghost]

when chicks see me they lay eggs!

I keep telling you ......telling an angry woman to calm down is like trying to baptize a cat.

[Ace]

Yep, can't think that they would be made anywhere else these days.

Interestingly, your 0 psi reading starts a bit higher than mine, so they might be a little different. My 0 psi starts at the stop, but yours starts a bit higher up.

Mine has no oil in it to dampen the needle, so my need vibrates a bit when running.

As I was sitting next to my bike having pulled the airbox, carbys, 3&4 exhaust pipes off and various other things, I noticed I read the gauge wrong. 0 is marked when there is no pressure and the graduation are 10 psi.  Therefore what I thought was 2 psi was actually 12 psi.

Anyway, I've ordered a new seal for the middle of the oil pump as mine is hard and now cracked.  I was pulling the engine down to fix an oil leak that way annoying me and found another issue. Head gasket had blown through to the return stud on the #1 cylinder in 1 place and nearly 2 others. I think because of this I thought #1 was running rich when it was in fact the plug was getting oiled.  Another thread from a while ago.

[AJK]

Hi Ace,

I see what your talking about with the gauge. Looking at them a bit closer, both yours and mine are actaully graduated the same. Your right, you were getting 12 psi as its part way off the stop. Thats good news anyhow.

Sorry to hear about the head gasket issue. I can say that clean and flat surfaces, together with a thin coat of 'copper coat' on both sides of the gasket and slight overtorquing (I.e. torque to 19 or 20 ft.lb) instead of what the book says should see you trouble free. I torqued mine to 20 ft.lb which was over by a few ft.lb & no issues. I leave it overnight then re-torque to the same spec again the next day to allow the gasket to compress & settle.

Let us know how you get on with the pump seal when you get around to it.

[Ace]

Oil pump seal...well isn't that fun to take out and install. Sharpened a screw driver up to leave out the old seal, didn't that take some getting out and slight damage to the soft metal surrounding. Not too worry, all done.

Reason for wet plugs was the orings at the bottom of the sleeves, the big ones that are 64mm or something, oil was getting past them and then into the chamber. Flame ring failed on 2 cylinders in parts as you could see the burn trail.

Oil pressure on start up about 75 psi. Once hot running at 60 mph 4200 rpm, 50 psi. At idle 1400rpm hot engine about 10 psi.

Clutch issue - well I didn't put the gear shifter (arm with the wheel on it) in the correct place, the wheel was sitting on the shifter drum between the inner and outer plates, one plate bent. Fixed that, changed out the little oring as well. Now if I pull the clutch lever in and downshift straight away I grind the gears a bit, if you pull the clutch in and wait for a second or so for the revs to drop which it should do because you pull the clutch in (not instantaneous on my bike) you can downshift without grinding. Neutral is getting easier to find and lets not forget only 2000 kms on the tranny. Clutch still bugs me though, I wonder if the wait a second or so is normal (I don't think so and am open to suggestions/ideas about it).

Best of off, no oil leaks yet after 100 mile run. (I'm touching a wooden table).