CB650 SC Oil Cooler for CB750's

[Piute]

              THX.BlueNose

[alfa750]

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[Piute]

   Well as stated winter coming on cooling wasn't needed the faring was,Glad this was brought forward ,I will be taking a nother fit and and ordering what is needed for one of the two to work,Then look deeper into the other,Sure the 650 can be had with lil work on the F2,I'm sure.

[alfa750]

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[alehman]

Came across this thread and wanted to share my experience attempting to adapt an 83 cb650 sc oil cooler to my 79K. It does not fit. The filter bolt hole on the engine sticks out too far, meaning that the cooler's adapter plate doesn't seal against the engine. On top of that, the fins on the adapter hit the engine case and would have to be cut off. Even then I'm pretty sure the oil lines coming from the adapter, which are inflexible metal tubes, wouldn't clear some fins on the engine case. Some more creative cutting/grinding would be called for.

If anyone else has made this mod work, I'd love to know how. If not, I'd be really interested in know what aftermarket adapter plates exist out there that people have used.

[alehman]

hey TOOLS, just went back through here and saw your post where you described the same problem. Did you ever get the 4" aluminum pipe to work?

[TOOLS1]

Yes I did. Just made a 5/8 inch spacer, and used a longer oil filter bolt. I think it was from the F-3.
TOOLS

[IVPeters]

Long time forum lurker, first time poster. I had been keeping an eye on this thread as I have also been working on making the 650 cooler plate work on my 750 K7 engine. I appreciate everyone's info!
I went the route of chucking the plate in a lathe and removing material where the plate contacts the case (dark spots are voids in the casting).

I only cut as far as I was comfortable (didn't want to cut through), so there was still about an 1/8" gap between plate and case, I turned a spacer to make up that gap.

Anyway, I just started/broke-in the engine a couple weeks ago after a rebuild, I didn't install the plate/cooler as I was looking to minimize the number of things that could go wrong when doing a first time start-up
The engine ran great! I'm at the point now where I would like to install the oil cooler and my main question is has anyone measured any oil pressure drop over their oil cooler? (Specifically the lines and radiator from the CB650)

Since we're plumbing a cooler on the pressure side of the pump I'm concerned about losing some oil pressure - I've heard of people tapping a cooler in between the scavenge side of the pump and the hose back to the oil tank to avoid pressure issues, but I'm wondering if it's even a issue.

[TOOLS1]

It should not be an issue. Honda must not have been worried about it, or they would not have installed the oil coolers in this way. Also I once lost an engine that had an oil cooler plumbed in this way because it blew the oil line apart, so use good high pressure lines.
TOOLS

[IVPeters]

Thanks Tools, I agree with you - I'm mostly paranoid with it being a freshly rebuilt engine.