Topic: 650 cam in a 550 revisited

[buffalogt750]

Just installed a 650 cam in my 1976 550K. No cam lobe clearance problems as some have had. Had to use 650 tach drive and 650 tach. Bike has stock 4 into 4 exhaust, Dyna 5 ohm coils with stock points, Accel copper core wires with non resistor caps, pod filters, 115 mains, all other carb settings stock. Noticeable power improvement especially at higher rpms. Cam was installed after other mods were done and tested to honestly evaluate just the cam. No issues or problems whatsoever. Probably a better power gain for the money than any other single mod you could do.

[kayaker43]

Amen,.. it should be the first mod if you ask me!

[FunJimmy]

I've recently installed the 650 cam too and find the improvements quite noticeable.
Engine is still to fresh to take it to the moon, but look forward to finding out how strong the top end really is.

[fuzzybutt]

wow, did george washington ride that 550? that 1776 550 is a rare one alright    but seriously thats cool, i had been wondering how much of an improvement that would be. i have a neighbor that just got a 550 and was wondering what kinds of cheap mods she could do.

[buffalogt750]

One thing to add. My 35 dollar ebay cam was within factory specs. Be sure to measure any used cam to be sure it is OK before you install it. Specs are available in 650 service manual on this site.

[Ryan 550k]

I'm in the middle of a rebuild with my 78 550 myself right now.  Hope to be finished in about a month.  I replaced 550 cam with 650 as well.  Love to hear it worked out so well Buffalo!  I'll report when I'm finished.

[hymodyne]

this is good news. when my 550 motor gets here, I'm going to install the 650 cam I've been holding on to for about a year...

hym

[Flying J]

Does anybody know if a regrind or the 650 cam gives better performance?

[FunJimmy]

A regrind of the correct profile will run circles around the 650 cam.

[mlinder]

A regrind of the correct profile will run circles around the 650 cam.

I think the idea is a cheap, easy performance upgrade. A 650 cam is that, compared to a regrind. And by "correct profile", what do you mean? Correct for what?

[FunJimmy]

I think the idea is a cheap, easy performance upgrade. A 650 cam is that, compared to a regrind. And by "correct profile", what do you mean? Correct for what?

Correct for your build. Compression ratio, ports, intended use, etc etc.

[mlinder]

I think the idea is a cheap, easy performance upgrade. A 650 cam is that, compared to a regrind. And by "correct profile", what do you mean? Correct for what?

Correct for your build. Compression ratio, ports, intended use, etc etc.

Well, of course. But that's a different build altogether. No point in a lumpy grind on an unported, stock compression, stock input and stock exhaust bike. It's a whole process. A grand and a half for headwork, half a grand for pistons, another grand and a half for intake and exhaust, another half a grand for bits to make #$%* work well, and the 400 dollar regrind is small potatoes, cost wise.

[Flying J]

Im just wondering what the best way to go would be for stock pistons and a mild port job. Would the 650 cam take full advantage of the "Mild" port job or would the port job not be enough for the regrind to make sense.

[buffalogt750]

If you want to spend the money, I'm sure a mild street regrind would make more power with a mild port job than a 650 cam. I don't care to spend a ton of money on a 30 plus year old bike. A CB550 is always gonna be a CB550. You can spend thousands  on it and still be blown away by almost any bigger or more modern bike. I wanted to see the benefit of a very cheap and very easy modification. For the money and effort required, a 650 cam is a worthwhile modification.