Topic: cb 650 cam to 550/500 what modifications have to do?

[kranta]

so what modications ihave to do if i put 650 cam to 550 or what parts i have to change?

[Scott S]

 You have to  put the 550 cam chain sprocket/gear on the 650 cam. You will also most likely have to clearance the head a little bit to clear the cam lobes. Where and how much varies from bike to bike. It can be done with a  Dremel tool.
 And, of course, cam chain and valve adjustment.

[DaveBarbier]

I may be mistaken, but I think you'll also need the tach drive gear and a tach gauge with a 650 ratio.

[Restoration Fan]

I may be mistaken, but I think you'll also need the tach drive gear and a tach gauge with a 650 ratio.

If you're going with the mechanical tach, maybe so.  But I believe that cal and a few others run a magnetic tachometer that reads from pickups on the front sprocket.

[Bailgang]

I may be mistaken, but I think you'll also need the tach drive gear and a tach gauge with a 650 ratio.

+1
750 tachs have the same ratio as the 650 tach which is what I used on my 550 when I swapped a 650 cam in it.

[Bailgang]

I may be mistaken, but I think you'll also need the tach drive gear and a tach gauge with a 650 ratio.

If you're going with the mechanical tach, maybe so.  But I believe that cal and a few others run a magnetic tachometer that reads from pickups on the front sprocket.

Do you mean electronic speedo maybe? I can't see how mag pick ups on the front sprocket will work for a tach especially if bike is in neutral.

[Restoration Fan]

Do you mean electronic speedo maybe? I can't see how mag pick ups on the front sprocket will work for a tach especially if bike is in neutral.

You're right.  Brain fart.  My bad.

[Bailgang]

Do you mean electronic speedo maybe? I can't see how mag pick ups on the front sprocket will work for a tach especially if bike is in neutral.

You're right.  Brain fart.  My bad.

It's all cool, I'm still on my first cup of coffee.

[kranta]

ok, thanks!

[goldarrow]

Be sure to test fit the 650 cam on to the head, spin it by hand and make sure cam lobes don't hit the head

[Kenzo]

How often are there clearance issues with the 650 cam in a 550? Most of the post imply simple easy drop in power improvements.

Where is the best place to source these cams?

TIA
Kenny

[RAFster122s]

Used cams turn up here occasionally but they are often bought on eBay.  They can go for $100 or even higher sometimes. Good price is generally around 70-75 for a good cam and tach gear.

[DaveBarbier]

Used cams turn up here occasionally but they are often bought on eBay.  They can go for $100 or even higher sometimes. Good price is generally around 70-75 for a good cam and tach gear.

If you could find one for that cheap then that would be great. I've seen them range from $120-$200 with just the cam and sprocket. Funny how much the price drops for the '83s and later. Saw $30 for both cams (DOHC) on eBay. But of course you need '79-'82.

[SOHC4 Cafe Racer Fan]

Used cams turn up here occasionally but they are often bought on eBay.  They can go for $100 or even higher sometimes. Good price is generally around 70-75 for a good cam and tach gear.

If you could find one for that cheap then that would be great. I've seen them range from $120-$200 with just the cam and sprocket. Funny how much the price drops for the '83s and later. Saw $30 for both cams (DOHC) on eBay. But of course you need '79-'82.

You also need to be careful about buying a cam on eBay.  Low resolution pictures or not showing every lobe on the cam can hide a roached/pitted or overly-worn cam.  You can also get a hardweld cam for about $360 ish (Dynoman).