Topic: Cam holder question

[Rio83]

Should one of the oil passages to the cam be blocked off like this? Or should it go through and to the underside of the cam holder? CB750 K2.

[Rio83]

Short clip of where it stops in the stud hole.

[newday777]

What bike is this on?

[Rio83]

Sorry. Cb750 K2😉

[madmtnmotors]

Clean out the bolt hole. I think you're missing the continuation with your drill bit as I believe the oil feed angles more sharply downward than you are doing with the drill bit. I would suggest a good cleaning of all those valve train components. If that oil feed were blocked then that cam cradle would be toast.

[Rio83]

No, I tried several angles. No hole🤔

[MRieck]

Replace that Rube Goldberg mess.

[madmtnmotors]

No, I tried several angles. No hole🤔

After cleaning it?

[Rio83]

After cleaning it and blowing with compressed air. Should all the four passages be the same?

[HondaMan]

There are 4 holes that oil the cam journals (2 on each bearing housing, in the bearing), and 4 more that squirt oil out onto the cam lobes while it rotates in front of them (2 on each bearing housing, look inside the back of the bearing assembly for those others). You can clean them (backward) by spraying solvent into the holes, like brake cleaner or carb cleaner sprays with the little plastic tube on the can.

[Rio83]

Ok👍 But ther should be 4 similar oil passages? Not one wich is blocked off?

[PeWe]

I spray good degreaser in all holes, CB750 cam holders. Chain cleaner spray work fine. WD40 ok too.
Blow with compressed air several times, blocking and spray thru different holes.
I block other big hole with finger to get higher pressure in small holes.

[Rio83]

Thanks Pewe👌 Ok👍 But ther should be 4 similar oil passages? Not one wich is blocked off?

[HondaMan]

Here's some pix of a normal cam bearing.
The "Cam Bearing 1" and "Cam Bearing 2" show 2 typical oil ports to the cam journal's bearings. One of the others in this pair of bearings missed going thru the bolt's hole, sometimes they are like that (they were probably just drilled in a jig, on a mill or drill press). The third picture shows the main journal's end cap on the backside of a bearing: that's where the hole you are testing should end up. If you suspect grit or filings got in there, try blowing it out from the infeed port on the bottom of the bearing, blocking off the one on the opposite end to ensure flow out this hole. I just use my finger to block it. Then fish a small wire down into the hole, all the way back to the journal's hole. If you must remove the little end plug to verify this distance, you can tap in a small screw to the hole after removing the end cap, or if you know someone who sells metric caps you can try that approach to reseal the original hole.

[Rio83]

Thank you Hondaman☺️ So all 4 bearings should for sure have the same oil passage?

[Rio83]

[Rio83]

Nobody knows??

[HondaMan]

Well, as they were hand-drilled, some have the side of the oil's passage hole open to the bolt's hole, and some don't. I have 2 that "missed" the bolt's hole entirely, but work fine, so they look different from the others. Just make sure that yours goes past the bolt hole and all the way into the oil journal's hole across the back of the cam bearing casting. Then it should work fine. I'd suggest blowing some brake cleaner (or similar solvent) thru them all the way back to the feed hole from the head, just to be sure there's no debris inside. One little chip can cost the bearing!

[Rio83]

That answer all my questions. Thank you very much☺️👌