Author Topic: RE: 1972 CB750 Please Help Me Identify Cam X (Read 6989 times)

chewbacca5000 · « **on:** August 21, 2012, 08:41:06 PM »

I have a cam with no R series markings and am wondering if it is an aftermarket cam? Did Honda ever make cams without the R stampe ie.R11. All it has on it is a circle with an X inside of it.

Thanks!

HondaMan · « **Reply #1 on:** August 21, 2012, 09:05:19 PM »

Nope, that's not a Honda cam. Those wide lobes look like at LEAST 225 degrees, maybe more. How much lift does it have? That might help ID it, too.

chewbacca5000 · « **Reply #2 on:** August 21, 2012, 09:08:54 PM »

Quote from: HondaMan on August 21, 2012, 09:05:19 PM

Nope, that's not a Honda cam. Those wide lobes look like at LEAST 225 degrees, maybe more. How much lift does it have? That might help ID it, too.

I have no idea. Just took it apart and now I have no idea how to get it back together.

scottly · « **Reply #3 on:** August 21, 2012, 09:10:35 PM »

Look at both ends of the cam for stamped markings.

chewbacca5000 · « **Reply #4 on:** August 21, 2012, 09:15:01 PM »

Quote from: scottly on August 21, 2012, 09:10:35 PM

Look at both ends of the cam for stamped markings.

There is none on the side with the horizontal line not sure about the side with the plastic retainer disk. I will check it out and let you know.

Thanks!

Terry in Australia · « **Reply #5 on:** August 22, 2012, 01:51:14 AM »

Yep, if it's an aftermarket cam, I'll probably be marked with the lift etc on the end with the retaining washer and bolt. Take the bolt out and have a look. Don't take the sprocket off, if it's been timed with a degree wheel you don't want to mess up the timing. Cheers, Terry.

chewbacca5000 · « **Reply #6 on:** August 22, 2012, 04:46:13 AM »

Quote from: Terry in Australia on August 22, 2012, 01:51:14 AM

Yep, if it's an aftermarket cam, I'll probably be marked with the lift etc on the end with the retaining washer and bolt. Take the bolt out and have a look. Don't take the sprocket off, if it's been timed with a degree wheel you don't want to mess up the timing. Cheers, Terry.

Too late for that already took it apart. I found a J on the other side opposite of the X, and there are too slashes pretty close to each other on the other end. Nothing else is written.

The sprocket s non adjustable from the looks of things. My main concern is being able to time it correctly. If the sprocket is non adjustable shouldn't I be able to put it back together and be ok?

HondaMan · « **Reply #7 on:** August 22, 2012, 03:51:21 PM »

It will run when reassembled, but will run BETTER if you can degree in the cam lobes. I don't think I've met an aftermarket cam that just dropped in "on the mark" since the 1980s.

chewbacca5000 · « **Reply #8 on:** August 22, 2012, 06:44:39 PM »

Thanks Hondaman,

This engine is starting to get really interesting today I noticed that the crank has been modified with set screws instead of the ball plugs. I wonder if the earlier engines had set screws?

Also the head gasket is copper with a rubber coating. I would like to reuse if possible, or get a new one just like it. The cylinder block has been resurfaced and the new head gasket appears thicker.

It also has the 1 piece oil rings, no seals on the exhaust, old style guildes, free spinning cam rocker shaft, and the ports have been modified. Maybe just matching or some funky port job. Also, the combustion chamber looks like it is right out of your cheap performance section in your book with the deep cuts in the combustion chamber smoothed out.

I have found corrosion on the piston wrist pins, and the final drive bearing. Man I hope there is nothing wrong with the crank.

Here's a couple pics.

scottly · « **Reply #9 on:** August 22, 2012, 07:16:43 PM »

Kind of difficult to degree the cam without having any specs. What size is the bore? The stock cranks all had the balls, I think.

chewbacca5000 · « **Reply #10 on:** August 22, 2012, 07:35:52 PM »

Quote from: scottly on August 22, 2012, 07:16:43 PM

Kind of difficult to degree the cam without having any specs. What size is the bore? The stock cranks all had the balls, I think.

Standard size. Do you think this head was tweaked? Looks like someone went to alot of trouble to smooth things out?

scottly · « **Reply #11 on:** August 22, 2012, 07:42:43 PM »

It looks like the intake ports have had some work, smoothing out the casting marks.

jerry h · « **Reply #12 on:** August 22, 2012, 08:39:57 PM »

The intake ports must have been a quick factory "clean" up of rough castings? Here's a look down my K2 - exactly the same as yours....
Frame date is 2/72

chewbacca5000 · « **Reply #13 on:** August 22, 2012, 08:47:52 PM »

Quote from: jerry h on August 22, 2012, 08:39:57 PM

The intake ports must have been a quick factory "clean" up of rough castings? Here's a look down my K2 - exactly the same as yours....
Frame date is 2/72

Thanks for the great pics! Looks like someone stuck a moto tool in there and went to get a cup of coffee! Real question is how does it run?

Have you had your engine apart? If so did you find 1 piece oil rings and no seals on the exhaust. I'll have to find that section in Hondaman's books that talks about these. He says they are good can't remember why. I can live with the smoke if it helps performance.

Terry in Australia · « **Reply #14 on:** August 23, 2012, 02:20:43 AM »

Can you posts a pic of your cylinder head looking down from the top mate? Someone's obviously had a play with your ports as they've all but deleted the bottom portion of the valve guides, but I'm wondering if it's a K1 head? That'd explain the exhaust valves not having seals, which of course reduces friction slightly, at the cost if puffing smoke on the overrun, if your valve to guide clearances are excessive.

If that cam has no markings and the sprocket isn't slotted, it's either a stocker, or it's like the Andrews "torquer" cam I had in my first K1, no additional lift, just more duration. That was a great cam, and the thing I liked about it was that I didn't have to degree it, it was a "drop in and ride off" deal. Cheers, Terry.

chewbacca5000 · « **Reply #15 on:** August 23, 2012, 04:46:13 AM »

Quote from: Terry in Australia on August 23, 2012, 02:20:43 AM

Can you posts a pic of your cylinder head looking down from the top mate? Someone's obviously had a play with your ports as they've all but deleted the bottom portion of the valve guides, but I'm wondering if it's a K1 head? That'd explain the exhaust valves not having seals, which of course reduces friction slightly, at the cost if puffing smoke on the overrun, if your valve to guide clearances are excessive.

If that cam has no markings and the sprocket isn't slotted, it's either a stocker, or it's like the Andrews "torquer" cam I had in my first K1, no additional lift, just more duration. That was a great cam, and the thing I liked about it was that I didn't have to degree it, it was a "drop in and ride off" deal. Cheers, Terry.

Maybe it's a K1 head the frame is dated 11/71. I like the sound of torquer! I'd better sell off my extra inventory and get a better bottom end. It probably is a drop in since it has no slot. Try to get some better pics after work today.

Thanks Terry!

Terry in Australia · « **Reply #16 on:** August 23, 2012, 01:34:55 PM »

No worries mate.

HondaMan · « **Reply #17 on:** August 23, 2012, 10:30:41 PM »

If it is a Torquer cam, cool! Action Fours made some like that, too, with 240-ish duration and stock lift. They were easy on the cam chain tensioners (and chain) and required no other mods to the engine, made them stronger in the 3000-6000 RPM range while winding to the 9200 RPM line with no valve float. But, theirs were not hard enough, so most of them wore out by now and are gone.

If I ever get to make my own cams, it will be on this philosophy.

wrenchmuch · « **Reply #18 on:** August 24, 2012, 06:41:07 AM »

Replacing the balls that seal the drill holes in the crank with Allen bolts usually means that some one has removed the balls to clean out the cranks passages.

754 · « **Reply #19 on:** August 24, 2012, 10:19:36 AM »

Sure hope you checked valve clearances BEFORE you took it apart..

Some cams are mared on flat spot between lobes, but I think you would have seen it.

Measure the dang lobes already..

chewbacca5000 · « **Reply #20 on:** August 24, 2012, 01:02:19 PM »

Quote from: 754 on August 24, 2012, 10:19:36 AM

Sure hope you checked valve clearances BEFORE you took it apart..

Some cams are mared on flat spot between lobes, but I think you would have seen it.

Measure the dang lobes already..

I will make a short video and you guys will have to walk me though it if I get it wrong. Thanks 754.

chewbacca5000 · « **Reply #21 on:** August 24, 2012, 01:47:25 PM »

Quote from: 754 on August 24, 2012, 10:19:36 AM

Sure hope you checked valve clearances BEFORE you took it apart..

Some cams are mared on flat spot between lobes, but I think you would have seen it.

Measure the dang lobes already..

I did not check clearances I had "wrench fever" that day. Here's video not sure if I am measuring correctly or not.

http://youtu.be/oZrTfBRijho

Thanks!

Terry in Australia · « **Reply #22 on:** August 25, 2012, 01:58:37 AM »

To meausure the lift you need to subtract the OD of the cam's "base circle" from the total distance that you measured from the heel of the cam, to the toe.

Without me measuring one it looks to be stock mate, but as I said once before, the "torquer" cam is around the same lift as a stocker, so it could still be, but the trouble is, you need a known stock cam to compare it to to know for sure. The lobes on your cam appear to be more "rounded" that a stocker, and that's a good thing, as it leads me to believe that it could be a torquer.

Interstingly enough, I went thru my cam collection (God know's why, but I've got a dozen or so stock K and F2 cams in a crate out in the "Tardis", as Cliff refers to my garage) and I've got 2 or 3 "odd" ones with unusual castings on them

If you like, I'll measure a stocker tomorrow, and tell you what the lift is. Cheers, Terry.

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Author Topic: RE: 1972 CB750 Please Help Me Identify Cam X (Read 6989 times)