Topic: Modified 550 cam cover for cam degreeing

[Scott S]

 Found this on the interwebs. I have a couple of spare covers and plan on doing to degree in the cam on my current build.
 A few questions... Do all of the rockers need to be in the cam cover or just a couple to use the dial gauge on? Is it OK to put a few bolts around the perimeter or should all of the bolts be installed? What's the best way to cut the cover? Dremel? Hacksaw blade?

[calj737]

Drop to your machinist and have him use an End Mill. There's no reason he couldn't also widen the chain channel a touch too.

Brent W recently suggested all rockers and enough screws to Dave during his Hyena build.

[Scott S]

 Done! Nothing a cut off wheel and some grinding stones can't take care of!

[bwaller]

I suggest folks use the older covers to modify and save the upgraded ones.....unless you have a stockpile of newer covers Scott.

If all you're doing is degreeing the cam just use the #1 rockers. With a new build with aftermarket pistons & cam that needs clearance checks then best to install them all. Use as many bolts as keeps the cover tight. If you're only compressing two springs use more bolts at that end.

[Scott S]

 That is an old style cover. I have a few, so I could sacrifice this one.

 I'll have stock pistons/new rings, a CB650 cam and I milled the head .020 and have 1.00mm over intake valves. Think I should install all the rockers? Or just use the ones on the end?
 And why #1? Wouldn't #4 be easier since the degree wheel will be on that side?

 I'm asking....this is all new territory for me.

[bwaller]

Sorry Scott, I looked at the first picture and saw the newer version.

[bwaller]

Sorry Scott, I looked at the first picture and saw the newer version.

I always attach the wheel on the left end but I'm not using stock bits on the right end either so wherever you mount the wheel turn from the opposite end of the crank and install those valves. I don't think you'll have any clearance issues. So just check the valve clearance with the two valves and if there isn't an issue then you've saved a bit of time. Checking is always proper.

[Scott S]

 So.... Degree wheel on right, #4 rockers installed, turn from the alternator bolt?

[bwaller]

That'll work, just be sure the wheel is secure. Use as large a wheel as possible.

[DaveBarbier]

So.... Degree wheel on right, #4 rockers installed, turn from the alternator bolt?

I put my degree wheel on the alternator side and measured from the #1 cylinder. Everything was in view and it went fairly quick.



If you're interested, I just typed up a degreeing "how to". It may help if it's your first time. It's in my build thread and you can find it in the table of contents.

[Scott S]

 Thanks Dave! I'll definitely read up on it.
 What I'd REALLY like to know are the stock CB650 cam specs. I have the lift numbers. Do you have the duration? Opening and closing events? Meaning "so many degrees  BTDC", etc?

[DaveBarbier]

I do not, Scott. The cam I'm using is a Megacycle. I wonder if you could contact them and see if they know. They take the 650 cams to do the regrinds so they might have the info.

[SOHC4 Cafe Racer Fan]

Blac aka Bryan,

Here's How Scott did his degreeing cam cover.

[Scott S]

 Here are some CB 650 numbers from the lady at Megacycle. They look a little different than the numbers I measured using my cheapo calipers, but what do I know?
 Do these numbers look viable for a stock 650 cam?

 INTAKE

 .332" lift at .040, measured at zero clearance.
 223° duration
 105° lobe center

EXHAUST

 .318" lift
 228° duration
 108 lobe center

[bwaller]

Barbara has been in the game a long time! If you're good searching this site there will be a thread that lists all these stock model actual cam #'s plus several aftermarket. Sorry I cannot even remember the OP

[Scott S]

 A lot of the 650 cam info is stuff I posted! There just doesn't seem to be much info out there.
 I have a friend (pro mechanic) that has degree'd cams before and is going to help/teach me. I'll be SURE to document as much as I can when we do it.

[innovativems]

Not trying to hijack but is there any reason I couldn't do the same for my cb400f?  Be a heck of a lot easier to degree my cam


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[bwaller]

It might well have been your thread Scott. I searched until my head ached and I found your thread, but I had offered actual #'s from both a Web38a and M-Cycles 126-20 and didn't see those so not sure there still isn't another thread.

[flatlander]

might be this one?
http://forums.sohc4.net/index.php/topic,134461.0.html

[bwaller]

Thanks, that's the one. Was starting to think I was losing it!

For opening/closing numbers the early 750's were (in) 5-35 (ex)35-5. I think the 550's were the same, but square the cam and even the lobe centers.

[flatlander]

sorry, that doesn't mean you're not losing it 

[bwaller]

Understatement