Topic: cb650 cam in a cb550 question

[2ceebees]

I've looked in the faq etc, but haven't found the answer.  I've got a 75' CB550 and I'm looking for a 650 cam.  What years/models of the 650 cams are correct?

Thanks

[goldarrow]

Those are nearly unobtainable.  Look for 79-81  sohc 650

[cb650]

and 82 sohc4

[2ceebees]

So 79-82 will work it sounds like.  Yeah, ebay searches are not turning up much.

[RAFster122s]

79 was the recommended year as some changes were rumored to have been made on later year model camshaft.
You will see improvements from any of the cb650 sohc camshafts because of increased duration.

[cb650]

All the 650 sohc cams are the same.  Except the lopo german cam.   Dought you would get one of them.   79 was a slightly faster bike but it wasnt the cam.

[2ceebees]

"lopo german" cam?    Not sure what that means.

[Bailgang]

"lopo german" cam?    Not sure what that means.

lopo=low performance. I don't know the specifics but from what I understand the 650's sold in Germany at that time had considerably less HP than those exported elsewhere. The cams in the engines sold in Germany had a much milder profile and are not the cam of choice if you're going to swap it into a 550.

[2ceebees]

Ahh...  good info.  Thanks

[tvs avery]

I found mine by buying a whole cb650 top end on ebay. I got it for next to nothing because no one wanted to pay shipping. I contacted the seller to see if he would just send me the cam, he was more than happy to. He got to sell the other parts and I got a cheap 650 cam with cheap shipping. So I suggest searching for "cb650 engine parts" or "cb650 top end" or "parts bike" as opposed to just the cam. Good luck.

[jinx2350]

I found one here from another member, with a cb750 tach. You'll need an appropriate tach as the gearing inside is different on cb550 than 650 and 750. 

I don't recall paying too terribly much for both. You should try posting in the wanted section.

[2ceebees]

Thanks for the info folks.  Had a pm from a member who just sold me a 650 cam and tach drive.  Score!

[alacrity]

I am thinking of doing this too-  with a 77 cb550k

Any chance there is another member here with a cam and a tach drive? 

[xsmooth69x]

going to do this with my bike too.

should i grab extra cams and drive gears?

[RAFster122s]

Cam needed, 550 cam gear used with 650 cam. If you are going with gear driven (cable driven) tach you will need the 650 cam's tach drive gear, or blank off & remove the drive gear and use a later electronic tach.

[Lars]

So. What's the gain...? The post from CB 650 indicates it does not give more Power??

[RAFster122s]

So. What's the gain...? The post from CB 650 indicates it does not give more Power??

Gives more power (torque and hp) through increased duration of the 650 cam when compared to stock cb550 cam. Don't know numbers because no one has done dyno runs for it to my knowledge. It is not huge, but it can be felt as well as seen when riding with stock and modified cb550.

[cb650]

So. What's the gain...? The post from CB 650 indicates it does not give more Power??

Where did I say that?     I've only heard good things about the swap.

[RAFster122s]

I believe he probably misunderstood your statement about the cams not being different on the CB650 as not being different from the CB550 to CB650...
You indicated other than the German market ones that were a different grind and fairly rare for most of us, the CB650 cams were all the same and any from '79 to '82 fit the CB550.

For the CB550 with a CB650 cam, you will use the CB550 cam chain drive gear and the CB650 tach cable drive gear with a CB650 or CB750 cable driven tach.  The other option is to omit the tach cable drive gear and to use an electronic tach.

David

[cb650]

Ok BUT BUT I never said no more power?   No matter I just dont want to be contributed to the " No it cant be done as it wasnt engineered that way" crowd.
 

[Bailgang]

So. What's the gain...? The post from CB 650 indicates it does not give more Power??

I think you misunderstood cb650's post as well, what he's saying is that all of the sohc 650 cams are the same except for the German cam meaning they will work but try to stay away from one that came from a 650 that was exported to Germany because those are different. It will still run with the German cam but you wont get the performance boost you're wanting because the German cam has a milder profile compared to the other 650 cams. 650 cams are getting harder and harder to find because this is a very popular performance mod for 500/550 owners and people who are parting out a sohc 650 know this and 500/550 owners wouldn't be doing this swap if there wasn't any performance to be gained.

I don't have side by side dyno numbers to prove it but I can tell you that from my own experience you will definitely feel the increase in power when swapping out the stock 500/550 cam with the 650 cam.

[2ceebees]

What I'm looking for more info on now is what other changes make sense when upgrading the cam.  Will it be a reason to change the jetting?

[Bootlegger56]

Keep your eyes open for a 650 parts bike with the motor intact.  I found mine here in NC for 125.00, scavenged the cam and tach drive, sold the header for 100.00 and still have the rest of the bike left.  I also pulled other parts to use in my 550 build like that nice alloy points cover which polished up nice instead of my rusty 550 chrome one.  All around it was a good way to go.