Topic: Oil pump

[gsb]

Hi!   

I have f1motor to rebuild .Motor was  never opened yet.Outside need repaint but inside look very good.i have book from hondamann but is my first rebuild so should i change only 3rings on pump and leave inside of pump untouched .pump spins very fineand smooth all screwes are untouched.Thanks for advices gsb

[ekpent]

Just for more info how many miles do you speculate is has on it ?

[Whaleman]

I would be inclined to not open it. In the past there was a guy that made new leak stopper rubbers which he sold with a new spring. If anyone has a link. I would change this if it is still able to be purchased. Also, don't try to pull the screen off unless you have to as they come off hard and a lot have been wrecked. Dan

[oldhatt45]

The members name is Elan.
If you go to personal messages and search for him, you'll find him.
Sometimes takes him a couple of days to reply but he will.
You probably want the Oil Stopper and the pan gaskets.

All reasonably priced.

I found the thread for the Stopper Assembly & Oil Pan Gaskets
http://forums.sohc4.net/index.php?topic=126362.msg1607215#new

Charlie

[PeWe]

The engine is over 35 years old and one must to do is the tensioners for Primary chains and cam chain.
The rubber is now closer to bakelite than rubber , small pieces of them will probably be found in the oil pan.

Check the slack of primary chains that can be done from the oil pan side. Slack is 65mm (new chains) to max 70mm which is what Honda say as service level.
I replaced all my chains in my last rebuild that only had 35.000km's since I replaced them during the 80's. Primary chains had 67.5mm in slack and I bought new HD cam chain again just for sure.

I should open the engine completely. Replace all chains with tensioners. (HD cam chain).
Check the crank bearings. New clutch.
Check head, valve seats might be corroded and need to be cut and lapped. Valves OK?
Complete gasket and seal kit....

[Whaleman]

I agree PeWe but keep in mind you are talking a serious amount of money. Dan

[PeWe]

Maybe  $1000US or less if all valves are OK.  And no bad surprise when lifting the cyilnder, pistons and rings..... 836 piston kit from Thailand is almost no money if new pistons are needed.

It cost some to just open and close ithe engine with new gasket set, sealer and seals... New 6mm bolts when the old x-bolts are horrible. A cheap 6mm thread kit of helicoil type is a must as well. I got  threads gone when releasing the bolts from the very beginning and still get it.

I did not open my oil pump. I tried, but bolts were too tight. I replaced all o-rings in the oil flow from pump and the other. I Trusted the protective mesh filtering all rubber stuff from tensioners and damaged clutch parts. My engine had only 96.000 km's
It felt ok when moving it flushing with solvent naphtha to remove old oil. Then new fresh oil in it and pump some before install.

Nice with a tight and leak free CB750. This was the difference back in the days compared with the UK bikes. I bought my bike early 1979, in time to see the  old BSA's, Triumphs and Nortons still on the road. Always a small lake of oil under the engines outside the cafe's.
CB750's dry and start direct with NO Lucas electrical, the man that invented the darkness.

NOT doing this can cost more, engine ruined.