[jjdugen]

Hi All
Just completed the rebuild of an imported CB350, nothing too major, it was in very good condition. I've been running the engine up in the workshop and after a good carb clean and balance it sounds lovely, revs freely etc.
Now, I do know that if this design has an Achilles heel, its the oil feed to the cam bearings. I have observed oil flow via the tappet inspection openings and oil is splashing about like a baby in a bath. But, I have noticed that the cam bearing boxes are running hotter than the cam box cover top plate. I would expect the top end of the motor to be roughly the same temperatures. Do these cam holders run hotter or do I have a potential oil feed problem?
Cheers

 

[ancientdad]

Did you take out the 6mm bolt in the left side of the rocker box to check for oil flow there? It's the best way to be sure, and if you have no leaks from either cam bearing near the valve adjusters (coming from behind the cam bearing) it likely means you have the cam bearing gaskets on correctly (they can be put on backwards and that causes a leak in the area). This bolt in the pic below

View attachment 274298

 

[jjdugen]

Thanks Tom, to be checked once I have the tank sorted and re-installed. Actually, I needs to know, will hook up a dummy tank tomorrow and run her up. Just to be sure, I take it this bolt is inside the points box or is it external?
Cheers.

 

[Yendor]

That Bolt is outside of the Point Cover.
It seals an Oil Passageway.
With the motor running there should be a flow of oil from the hole.

Be preapred to put it back in.

 

[ancientdad]

It's a bolt, and it's in the upper right corner of the rocker box at about 2 o'clock in relation to the points cover. It's the only 6mm bolt (10mm head) in that area, and it has a sealing washer on it. Get it running, then take the bolt out for a couple seconds... if oil is getting to the top end, it will immediately come flowing out of the hole - be prepared to sop it up with a rag and get the bolt back in or shut off the engine, or it can make a mess... but it's good to know for sure. Wish the 450 had one like it, but they don't.

 

[jjdugen]

Invaluable information, thanks guys. As I say, I have no problem with the CB77's (not that they have a problem running in ball bearings) but I am still finding my way round this one.

 

[Crashoverride]

Cool, never knew that was there for checking.

 

[JamesPal]

It's a bolt, and it's in the upper right corner of the rocker box at about 2 o'clock in relation to the points cover. It's the only 6mm bolt (10mm head) in that area, and it has a sealing washer on it. Get it running, then take the bolt out for a couple seconds... if oil is getting to the top end, it will immediately come flowing out of the hole - be prepared to sop it up with a rag and get the bolt back in or shut off the engine, or it can make a mess... but it's good to know for sure. Wish the 450 had one like it, but they don't.

Tom, I believe oil feed/pressure to the 450 DOHC top end can be checked with one of the cylinder head stud nuts. The two on the right hand side have sealing washers. If loosened oil will come out under pressure. Of course loosening a head stud while the engine is not a good idea, but at idle for a few seconds...? I think I read this in the FSM, but not sure. When I built my motor I started it up and then shut it down and pulled the valve covers. It was pretty clear oil was coming out of both cams under the rocker arms.

 

[12ozPBR]

Tom, I believe oil feed/pressure to the 450 DOHC top end can be checked with one of the cylinder head stud nuts. The two on the right hand side have sealing washers. If loosened oil will come out under pressure. Of course loosening a head stud while the engine is not a good idea, but at idle for a few seconds...? I think I read this in the FSM, but not sure. When I built my motor I started it up and then shut it down and pulled the valve covers. It was pretty clear oil was coming out of both cams under the rocker arms.

That’s right Jim. The right front cylinder head nut on all 450’s to check for oil flow. I too think it’s in the FSM but it’s also the info provided for the CB450 4 and 5 speeds in the Honda Motorcycle Service Specifications for all models 1959-1980.

 

[ancientdad]

Yeah, I was aware of it but I just hate untorquing one stud by itself, plus the mess... but I did run my 450 with the exhaust valve cover off after the second oiling issue I had, just not for long and with a cloth under the valve cover area. I plan to never wash that bike, it's oil-tight so I'm going to keep it clean so all I have to do is wipe it down