cb450 rebuild

[strokinout]

Okay, I hate posting new threads as I prefer to research and find out answers to my questions on my own as I usually find a lot of other interesting tid bits of info along the way. But this is just eluding me. I'm currently doing a frame off on my 1974 cb450 that's been sitting for a very long time. Frame has some rot, engine needs rebuilding and pretty much everything needs to be replaced. But I got the bike for a song so it's worth it and the experience gained. I started tearing down the motor and found this.

 

[strokinout]

My question is more about the motor then anything else. It's looking like the valve head, pistons and cylinders will need replaced. Does anyone know if later model cb450 engines have parts that will swap over?

 

[kosmjon]

I feel your pain. I had a CB360 whose insides looked like that. Must've been hard-water with lime and calcium that basically become like concrete. It actually ate away some of the aluminum around the steel valve seats. I ended up replacing the cylinders, pistons, rings, and cylinder head (and I vowed to in future start with an engine that at least turns over.)

I'm finishing up a CB450 right now and it had one piston stuck bad enough that I bought new cylinders, pistons, and rings for her. On the plus side I recently fired her up and she ran great, but failed to shift due to a (ever so slightly) bent a transmission fork. I found an entire trans on ebay for $55 shipped and she is back together and all good now.

What I'm saying with all this is you should easily be able to source a new cylinder head and w/valves (and other parts) from ebay. Personally I would try to stay with top-end parts from a 1969-1974 so it shouldn't be too bad to find.

 

[strokinout]

Yeah, whatever that stuff is, it was eating away at the piston. Even the rings were coming out in pieces. I plan to stay as close as I can with stock parts but I have a good line on early 80's cb450 cylinders with pistons and wanted to know if they can be used on my year motor. They gotta be replaced and it seems early 80's stuff is easier and cheaper to find.

 

[mydlyfkryzis]

80's CB450 are SOHC, 3 valves per cylinder. They are 360 degree motors with counter balancers. There are about 0 interchangeable parts motor wise. The 70;s CB450 are DOHC, 2 valves per cylinder. They have a 180 degree motor. An entirely different animal.

 

[strokinout]

Gotcha. Thanks a bunch. Sucks though because there seems to be a lot more 80's stuff available and for cheaper.