Topic: 650 cam in a 550 head conversion.....I ran into some trouble.....

[Ryan 550k]

Has anyone who's done the 650 cam in a 550 head conversion had any problems getting the cam chain around the 650 cam sprocket?  I loosened up the cam chain tensioner, placed the cam on the head and tried to pull the chain over the sprocket but it was just a bit too tight.....and by a bit too tight I mean it almost fit but there's no way it was gonna.  I was told by those who seem to know what they're talking about that any 650 cam from 79 - 82 would work.  I'm using a cam from an 82 650.  Maybe it's too big?  Help?

[mlinder]

You are using the sprocket from the 550, right, Ryan?

I think you can remove the sprocket from the camshaft, get the chain over the sprocket, then slide in the camshaft, and attach it to the sprocket. Can do that with other bikes, so I assume you can with this one as well.

[Ryan 550k]

#$%*, I have a feeling it might be the 650 sprocket.  Only because I was under the impression that was what was supposed to be used.

[mlinder]

#$%*, I have a feeling it might be the 650 sprocket.  Only because I was under the impression that was what was supposed to be used.

Nope, remember, I thought we switched it over already. Take a look at em. The 650 sprocket will not fit the 550 camchain at all. Look at them again.

[Ryan 550k]

Ya, I seem to remember switching them as well.  I think your right.  I'll take a look.

[Beans]

I'm curious on this conversion. Can u just swap in a new cam and go or do you have to do some mods to make the cam work.  I figure I would have to go to a bigger main jet but is it just swaping the cam and ur done?

[mlinder]

Beans, far as I know, it's been a direct swap for anyone who's done it. Clearances are a bit tight, but seem ok, at least on the 550 heads, not sure about the 500.

[Beans]

Beans, far as I know, it's been a direct swap for anyone who's done it. Clearances are a bit tight, but seem ok, at least on the 550 heads, not sure about the 500.

Ok cool just curious since I got my motor apart was thinking about doing the conversion but wanted to make sure before I did it on my 550.

[mlinder]

Beans, far as I know, it's been a direct swap for anyone who's done it. Clearances are a bit tight, but seem ok, at least on the 550 heads, not sure about the 500.

Ok cool just curious since I got my motor apart was thinking about doing the conversion but wanted to make sure before I did it on my 550.

It's a good idea to drop the 650 cam in and make sure the lobes don't hit anything before reassembly, though I'm pretty sure they won't.

[Beans]

Yea I don't think it will seen a lot of threads on this mod but will check to be safe.  Now I just need to find a 650 cam.   

[Ryan 550k]

I'm thinking that something might have been impeding the chain from loosening up all the way.  I'll be looking at it next week.  I'll let you know what I find.

Beans, MLinder is right.  A hand full of folks have done the cam switch and it seems to be a direct swap.  

[Beans]

Cool thanks guys I'm still learning these motors.  But not much different then my dirtbike except for 3 more cylinders.

[Ryan 550k]

Cool thanks guys I'm still learning these motors.  But not much different then my dirtbike except for 3 more cylinders.

So am I dude, so am I.

[mlinder]

Ryan, didn't we have to remove the gear from the cam to get it off? I might be confusing that with the 350t, can't remember.

[Sporkfly]

The 650 cam should work in the 500 as well. The Honda part numbers for the head between the 500 and 550 are the same. You will need the 550 cam sprocket, the 650 tach drive gear and a 4:1 tach (either a 650 or 750 tach will work), but other than that it will be a direct drop in. Check the service manual on the main page, and the tips and tricks section for getting the chain over the sprocket. There are a number of write ups on getting the chain over.

Just to reiterate, the 650 uses a cam gear rather than a sprocket so you will need to use the 550's sprocket on the 650 cam.

[mlinder]

Paul, the stock 650 cam is very similar to the mild street cam for the 550 offered by webcam, etc.
Supposed to increase midrange and top end a fair bit,

[brianzenk]

The trick is the chain goes on the camshaft
first then the sproket. The chain then goes
up on to the sprocket from the back. Be sure
to line up the sprocket markings correctly.

[mlinder]

The trick is the chain goes on the camshaft
first then the sproket. The chain then goes
up on to the sprocket from the back. Be sure
to line up the sprocket markings correctly.

Yeah, this. Knew it was something along those lines.