Topic: Where to Buy Top End Oil Jets?

[Xander^]

This side of my camshaft is definitely damaged and not useable right?... from all the metal to metal no oil contact

[seanbarney41]

Yup, that stuff is shot.  Note the gouges in that bearing journal, those are not supposed to be there.  Also the blue cam lobes...smoked.  first one I've seen where the center was worse than the ends.  Did you find o rings under the ends of both cam towers?...they often stick to the bottom of the towers.

[Xander^]

Yeah thought so.. im looking for a new camshaft and  holder/retainer .. are both holders the same? Or is left different from right??

Also, partszilla shows 2 different types of o-rings that go on the top end metering jets.. see picture below of my shopping cart..

[seanbarney41]

You will need new rockers too.  I would be very concerned about even the rockers associated with possible still good lobes, rocker shafts, even valve springs could have got over heated.

Reason u asked about o rings is, if outside ends of cam towers o rings were omitted or damaged by po, the oil jet could have been ok, and the similar damage may result.  You need all 4, 2 for inside end of cam towers where the oil jets are, and 2 outside for the blanked off hollows in the head.  The size of the o ring changed from early to late, so measure your hollows and jets and get the corresponding size

[Xander^]

You will need new rockers too.  I would be very concerned about even the rockers associated with possible still good lobes, rocker shafts, even valve springs could have got over heated.

Reason u asked about o rings is, if outside ends of cam towers o rings were omitted or damaged by po, the oil jet could have been ok, and the similar damage may result.  You need all 4, 2 for inside end of cam towers where the oil jets are, and 2 outside for the blanked off hollows in the head.  The size of the o ring changed from early to late, so measure your hollows and jets and get the corresponding size

The picture of the parts list there^ has both on the 1977 cb750k exploded diagram.. not sure why both were listed for that year when i will only use 1 set .. regardless the difference in both sets are 0.02mm .. i guess ill try to measure the holes but i might even be off by that much while measuring...

Also ive been trying to find a new cam .. even posted in the wanted forums list. If this issue was only on side of cylinder 1&2 i should only need hardware for that side right? Plus the whole camshaft obviously.

Are both camshaft retaining holder towers the same from side 1&2 to 3&4 ?

[seanbarney41]

I don't know about whether the cam towers are interchangeable side to side.  I know that it would be ideal to keep a whole valvetrain together as a set from a good running bike but it is not critical.  I have swapped parts and pieces with good success before.

I don't know what's up with that o ring situation either.

[PeWe]

CB750 Cam towers are the same 1-2 vs 3-4. Later version has no punched in markings, ink numbers.
I have read that very early had one for 1-2 and another for 3-4. Big problem if shifting them.
New model with holes for both oil channels.

I usually put them back as they were before. I have however bought 3 sets from eBay I had no idea how they have been used before.

[Xander^]

CB750 Cam towers are the same 1-2 vs 3-4. Later version has no punched in markings, ink numbers.
I have read that very early had one for 1-2 and another for 3-4. Big problem if shifting them.
New model with holes for both oil channels.

I usually put them back as they were before. I have however bought 3 sets from eBay I had no idea how they have been used before.

I see.. so i can get away with just a camshaft and 1 camshaft tower.. and a new topend oil metering jet lol

[bryanj]

Having had to do these way back for customers i would not do the job without a total strip down and clean out of all the cases and galleries

[754]

 FWIW, I blew mine up worse than that, wore 1/8 inch off the end journal, had spent the last he doing 60 mph on a mountain pass. we cut the frame , pulled it apart, then drove 4 hrs to my stash of parts.
 I spent about 2 hrs carefully cleaning out the debris on the low spots on the heads with Q tips. Got it running, rode about 50 miles, dropped the oil filter, and the housing was surprisingly clean, I expected lots of filings.  I had to surmise that most of it stayed up in the nooks of the head, and the rest got caught by the filter while I was running the bad cam.
 He will need cam , probably 4 rockers, maybe shafts, one cradle and it's matching caps.

[PeWe]

This has worried me too so I have had some thoughts about how the orifices can be blocked.
The oil transport up to the head goes via the oil filter direct from oil tank and pump. No dirt from engine can enter the head if filter is OK with its spring + washer. Dirt from engine blocked by the oil pump strainer, oil pumped by scavange pump to oil tank

If there is additional sealer around the 183 o-ring between cases above oil filter, around 2 o-rings between case and cyl, cyl-head or too much flowing sealer around rubber pucks under the cam holders, oil orifices can be blocked.

There is a risk when changing oil filter that something can enter the inside of the filter housing and can slip up to head.

If dirt will enter oil tank it will go straight thru oil pump and forward to the filter. So if a bad person put sand there, oil pump will suffer and filter should catch the sand.

Use of too much not really needed additional sealer on base gasket, head gasket and let dirt enter the filter housing during a filter change are the risks I have found.
I have never got the oil flow obstructed to the cam.

I blew the oil channel from pump to filter clean with pump removed when I changed oil pump to a pump with new rotors from MessnerMoto just for sure. This might be the alternative when cleaning engine after cam oiler issue.

[Xander^]

Thanks guys, going to keep that all in mind.. and going to start hunting those parts..
Maybe my metering jet will be okay after a good cleaning

[Xander^]

So ive pulled the top end metering jet out and the passage is still clogged...no air coming through when air is blown with compressor from the passage down where the oil pressure gauge goes.. other metering jet gets air.

Time to pull the head.... any idea how deep the clog could be?

[bryanj]

Somewhere between cam carrier and main gallery, not a lot of help i know but why i said you need to do a complete strip and clean mate

[Xander^]

Somewhere between cam carrier and main gallery, not a lot of help i know but why i said you need to do a complete strip and clean mate

Well hopefully the issue is somewhere in the head or the cylinder and not in the cases because my bike is at a shop as it initially went in for a safety inspection and a valve adjustments... getting to be a serious job lol..