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CB450 Camshaft & Follower Wear

lundy341

New Member
Joined
Feb 22, 2025
Total Posts
7
Total likes
3
Location
South Dakota
I've been rebuilding my CB450K6 engine little by little and noticed excessive wear (concave wear pattern) on 3 of the 4 cam followers. I scanned VHT threads and was able to learn that it's a common failure point on these bikes. I was able to find some used cam followers online that are in much better shape than my current ones. Both of the exhaust cam followers were worn along with the LH intake cam follower.

This is where my question comes in, I am concerned about the wear on my camshaft lobes. I am hoping that someone can tell me if my worry is justified or if I should proceed with getting the cams measured to see if they are within the service specifications. I've seen a lot of threads here where cams are showing large gouges, this isn't the case for my setup. My exhaust cam does have some small pitting and grooves. The intake cam appears to be in better shape but still has some wear grooves. At least this lines up with the wear I was seeing on the cam followers... Thanks in advance!

Intake Cam
1740712698620.jpeg

1740712768220.jpeg

Exhaust Cam
1740712863193.jpeg
1740712935047.jpeg

Cam Follower Wear Example
1740712982518.jpeg
1740713002916.jpeg
 
lundy341 said:
I've been rebuilding my CB450K6 engine little by little and noticed excessive wear (concave wear pattern) on 3 of the 4 cam followers. I scanned VHT threads and was able to learn that it's a common failure point on these bikes. I was able to find some used cam followers online that are in much better shape than my current ones. Both of the exhaust cam followers were worn along with the LH intake cam follower.
Click to expand...
What has happened to yours is fairly typical, and often exacerbated by owners not understanding the proper way to warm up a DOHC 450 before riding away. Because of the design of the head, there is no trapped or puddled oil beneath the cams to provide immediate lubrication on start-up. The oil that fills the camshafts from the passages up the two right hand cylinder studs drains out of the cam lobe orifices and back into the bottom end overnight, so it takes at least 1 full minute (sometimes as long as 2 minutes) to reach the cams and flow out of the orifices in the lobes to lubricate the followers on a cold start. I like to keep the rpms as low as possible during the first 1 to 2 minutes (idling if possible) until oil flow arrives so the film of oil left on the cams doesn't get burned through by higher rpm and friction. It was even mentioned in the early CB450 owner's manual.

CB450 manual2.jpg

This is the path of oil flow to the cams, and since it's a piston pump it only pushes oil on the inward stroke of the clutch basket-driven eccentric "pushrod".

450 top end oil flow.jpg

So with freshly repaired parts, if you follow that method you'll avoid most if not all potential damage in the future. I run my 450 hard most of the times I ride it and it has aftermarket cams in it as well, but given a good warmup, regular oil changes and decent maintenance you'll be fine.
 
LongDistanceRider said:
Ouch. The cam lobes will wear the replacement rockers fairly quickly.
Oregon Cam can regrind yours back to spec, the have masters made from NOS cams. https://www.oregoncamshaft.com/
Rockers can be rebuilt to spec by Rockers Unlimited https://www.rockerarms.com/
Click to expand...
I just contacted Oregon Cam and it sounds like they don't have a master for the CB450s. He did say that he worked with someone (I am assuming you) on making masters for a 350. I may have to try and track down a set of used cams, from what I've read that can be challenging with the exhaust cam.
 
ancientdad said:
What has happened to yours is fairly typical, and often exacerbated by owners not understanding the proper way to warm up a DOHC 450 before riding away. Because of the design of the head, there is no trapped or puddled oil beneath the cams to provide immediate lubrication on start-up. The oil that fills the camshafts from the passages up the two right hand cylinder studs drains out of the cam lobe orifices and back into the bottom end overnight, so it takes at least 1 full minute (sometimes as long as 2 minutes) to reach the cams and flow out of the orifices in the lobes to lubricate the followers on a cold start. I like to keep the rpms as low as possible during the first 1 to 2 minutes (idling if possible) until oil flow arrives so the film of oil left on the cams doesn't get burned through by higher rpm and friction. It was even mentioned in the early CB450 owner's manual.

View attachment 43058

This is the path of oil flow to the cams, and since it's a piston pump it only pushes oil on the inward stroke of the clutch basket-driven eccentric "pushrod".

View attachment 43059

So with freshly repaired parts, if you follow that method you'll avoid most if not all potential damage in the future. I run my 450 hard most of the times I ride it and it has aftermarket cams in it as well, but given a good warmup, regular oil changes and decent maintenance you'll be fine.
Click to expand...
Thanks for the information! I figured this was the case and it's good to have someone reconfirm my assumption.
 
lundy341 said:
I just contacted Oregon Cam and it sounds like they don't have a master for the CB450s. He did say that he worked with someone (I am assuming you) on making masters for a 350. I may have to try and track down a set of used cams, from what I've read that can be challenging with the exhaust cam.
Click to expand...
That should not be true - this thread by Jim confirms they have 450 masters

Cam regrinding and Rocker arm repairs

Oregon Camshaft https://www.oregoncamshaft.com/ is making masters of the intake and exhaust cams. That should be done in the next 30 days and they will be able to resurface/regrind your damaged cams. Thank you Chris, @12ozPBR, for supplying those cams. Rocker Arms Unlimited...
www.vintagehondatwins.com www.vintagehondatwins.com
 
ancientdad said:
That should not be true - this thread by Jim confirms they have 450 masters

Cam regrinding and Rocker arm repairs

Oregon Camshaft https://www.oregoncamshaft.com/ is making masters of the intake and exhaust cams. That should be done in the next 30 days and they will be able to resurface/regrind your damaged cams. Thank you Chris, @12ozPBR, for supplying those cams. Rocker Arms Unlimited...
www.vintagehondatwins.com www.vintagehondatwins.com
Click to expand...
Right, I saw that pinned thread so was pretty confused when the man I talked to had no recollection. I see that "Ken" is mentioned in that thread as being the Oregon Cam contact. I will call back and ask specifically for him.
 
lundy341 said:
I just contacted Oregon Cam and it sounds like they don't have a master for the CB450s. He did say that he worked with someone (I am assuming you) on making masters for a 350. I may have to try and track down a set of used cams, from what I've read that can be challenging with the exhaust cam.
Click to expand...
He made those masters the end of last year, I know he has them since he charged me for making them. Mention it's for the DOHC 450, separate intake and exhaust cams. He doesn't have the K0 intake.
 
A very late update here... Oregon Cams was able to regrind my cam shafts. It took some back and forth, they didn't initially remember they had the CB450 masters. They came back looking great!
 
lundy341 said:
A very late update here... Oregon Cams was able to regrind my cam shafts. It took some back and forth, they didn't initially remember they had the CB450 masters. They came back looking great!
Click to expand...
Good to hear, but a bit disappointing that they didn't even remember LDR sending them cams to work with and charging him for making the masters.

Can you post some pics of the cams so we can see the results?
 
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