CB450K camshaft timing mark problem

Highwayace

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Finland
Hi everyone,

I am working on a CB450K4 and run into a bit of a puzzle regarding the camshaft timing. According to many general resources, there should be clear timing lines on the camshafts. However, on my shafts, I cannot find any lines at all—only punched dots (as seen in the attached pictures).

Before posting here, I did some research. I checked the Factory Service Manual (FSM), but the illustration is quite grainy and vague; it looks like it might depict a line, but it is hard to say for sure. I also asked about this in an older group and on the Facebook Honda Twins group. The feedback there fell into three categories:

"Check the manual" (which, as mentioned, wasn't definitive).

"Yes, they are timing marks" (some members shared photos of their own camshafts which featured a clear dot).

"Maybe, maybe not."

Since this forum is known for its deep expertise on these vintage twins, I wanted to ask here for a more definitive answer: Are these punched dots indeed the official timing marks on certain production runs of these camshafts, or should I keep hunting for hidden lines?

Any insights or validation from someone who has run into these same dot-marked shafts during a rebuild would be greatly appreciated.

I'm not completely sure whether my bike should be classified as a K3 or a K4. The frame and engine numbers indicate that the bike was originally built in 1969, but many parts on it are clearly from later K‑series models — for example the newer‑style fuel tank and the front disc brake conversion.The bike was first registered in 1971, and the registration document lists it as a K4. Considering the age of the bike, it's very likely that many components have been replaced or updated over the last 55 years. I've spent this winter hunting parts from all over the world, so the restoration is definitely a mix of different K‑series generations.

Thank you in advance for your help!

BR Ilkka, Jyvaskyla, FinlandHonda-CAM_1.jpgHonda-CAM_2.jpg
 
Hi everyone,

I am working on a CB450K4 and run into a bit of a puzzle regarding the camshaft timing. According to many general resources, there should be clear timing lines on the camshafts. However, on my shafts, I cannot find any lines at all—only punched dots (as seen in the attached pictures).

Before posting here, I did some research. I checked the Factory Service Manual (FSM), but the illustration is quite grainy and vague; it looks like it might depict a line, but it is hard to say for sure. I also asked about this in an older group and on the Facebook Honda Twins group. The feedback there fell into three categories:

"Check the manual" (which, as mentioned, wasn't definitive).

"Yes, they are timing marks" (some members shared photos of their own camshafts which featured a clear dot).

"Maybe, maybe not."

Since this forum is known for its deep expertise on these vintage twins, I wanted to ask here for a more definitive answer: Are these punched dots indeed the official timing marks on certain production runs of these camshafts, or should I keep hunting for hidden lines?

Any insights or validation from someone who has run into these same dot-marked shafts during a rebuild would be greatly appreciated.
I'm not completely sure if they are original, obviously I haven't seen every version of 450 camshaft but the majority of cams I've seen do not have those marks. I traded a pair of used high performance cams done by Megacycle in 1992 for my build and they have dots for cam timing instead of horizontal marks.

1780660947718.png

I'm not sure if Megacycle made those during the regrind process but it would make sense, since they've been regrinding and refurbishing 450 cams since the late '60s and have refurbished thousands of cams for the 450 alone over that time.

Full pictures of your camshafts that show the timing dots, as well as the castings near them, would help determine if they are marked in the same location on the camshafts as mine are.
I'm not completely sure whether my bike should be classified as a K3 or a K4. The frame and engine numbers indicate that the bike was originally built in 1969, but many parts on it are clearly from later K‑series models — for example the newer‑style fuel tank and the front disc brake conversion.The bike was first registered in 1971, and the registration document lists it as a K4. Considering the age of the bike, it's very likely that many components have been replaced or updated over the last 55 years. I've spent this winter hunting parts from all over the world, so the restoration is definitely a mix of different K‑series generations.
A picture or two of your bike would help us. There's also the Honda ID Guide entries showing the frame numbers of the different K models (part of your Welcome Package) here:

 
Can you tell us which cam is which in your pictures? Top is exhaust and bottom is intake?
Based on the castings visible I'm guessing that is correct. I'd like to see full sized pics of each cam, 180° apart, so we can see the castings and where the dots are in relation to them, to compare with mine further.
 
Thanks Rob. And the dot is on the exhaust cam, which makes me wonder if it had been refurbished by Megacycle too since the exhaust cams are the usual victims of lobe and follower wear.
 
No idea if it was refurbished, one came from the engine that was in the bike and the other from the donor engine. They all had some wear but these were the best.
 
No idea if it was refurbished, one came from the engine that was in the bike and the other from the donor engine. They all had some wear but these were the best.
You don't happen to have any full pictures of the cams before installation, do you? Ones that show the castings and timing marks in the same pics?

I found this pic of my repaired exhaust cam after getting it back from Megacycle, note the casting facing outward when both the dot and original timing mark showing.

ex cam.png
 
I don't think the little "dot" showing in the top picture provided by the original poster is a timing mark for the exhaust cam. It doesn't seem to match up with mine, shown below.

f377a821-9263-48b9-80c8-a41d7739c96a-1_all_3133.jpg

The one in the second picture does appear to be a timing mark for the intake cam.
 
I don't think the little "dot" showing in the top picture provided by the original poster is a timing mar for the exhaust cam. It doesn't seem to match up with mine, shown below.
After a second look I agree, the tapered area of the casting is about 90° from that "dot". That camshaft might have a faint line where the mark actually is, which is why we need more full-sized pics of both cams to be sure.
 
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