Topic: Megacycle cam question

[scondon]

          Has anyone used the stock rocker arms (followers) with a Megacycle cam? While installing my 125/65 cam I noticed that the lobe surfaces are a bit rough. Megacycle strongly suggests using "hardened" followers but I'd like to hear from you guys before going forward. I'm sooooooooo close to getting this engine buttoned up.

          Engine is a '78 "836" F/K if that makes any difference.

[Sam Green Racing]

Hi Sean,

Don't worry about the surface of the cam.
Megacycle require you to use new or rehardened rockers.
If in dought have a word with the Head Master.

Regards Sam.

[Bodi]

Rough surfaces? Mine were pretty smooth.
You should use reground/hardened or new stock rockers because the used ones will have worn in to the old cam. Using them on a new cam can cause lubrication failure and galling because the rockers will only contact the cam at their "high spots" and the contact pressure is likely to be more than your oil can handle. New or reground rockers will have very flat contact surfaces.
Last time I looked Megacycle didn't have hardened rockers for the SOHC750 engine, just for (much) newer sportbikes.

[Sam Green Racing]

Megacycle will resurface your own rockers at a cost of $57.
I think you will find new ones are cheaper.

[Terry in Australia]

Sean, as you're aware I'm faced with the same situation, but I think that purchasing new/re-finished rockers is a load of hooey, IF your rockers are in good condition. I know it says to use new or resurfaced rockers in the installation blurb, but I still think it's bollocks.

I've got a box full of rockers (good ol' ebay!) and few, if any, are showing any major signs of wear, so I'll use the best set and I reckon it'll be no different from when I rebuilt my F2 engine, using used rockers and cam from several different bikes.

The surface of the megacycle cams (mine's a 125/75) are quite rough, but compared to the OEM cam and an "Andrews" cam I had in my K1 20-odd years ago before Andrews found Harley, or vice-versa, the whole casting is very rough. Megacycle must be the "Wiseco" of camshafts? Cheers, "sceptical" Terry.    

[Mark M]

Having had a little think about this I would like to point out that the ammount of wear that it would take to cause this Kind of lubrication problem would mean that the parts have probably already worn through the surface hardening and are now scrap anyway. 

Wern't 'chocolate cams' an 80's thing anyway?

[dusterdude]

do these engines have roller rockers,if not,they will eat into a new cam.roller rockers can be reused as long as they are not galled or have any serious wear.

[MRieck]

The rocker arms can be reused if they are in good condition (insepect them with a magnifying lens). New arms are cheaper than Megacycle hard welded units and personally I don't think it is a good idea to put that much heat into one of those rocker arms. Megacycle was doing alot of Ducati arms a few years back( secondary to poor hard chroming on Ducrappy's part) and there were problems with distortion. If I were to replace any pieces it would be the intake rocker arms secondary to the aggresive lift of the Megacycle 125-65 and 75. The exhaust opens gradually while the intake is "slammed" open.

[scondon]

 Thanks for the responses fellas. The rocker arms I have are from a '78 motor with 12 grand on it. They are in the best "used" shape I have seen i.e. no pitting,discoloration,wear spots etc. I also have a back up set from another 78 motor should any of them fail close inspection.

   The stock cam that I removed has shiny, smooth lobe surfaces while, in comparison, the Megacycle "billet" cam has a dull gray surface that feels like an oil stone when you run your finger across it. Your right Terry, the whole casting is a bit rough as if it were made of stone rather than metal.

   I don't like the idea of having Megacycle weld a surface to the rockers so I'll go with what I have and keep a close eye on the valve lash over the first thousand miles or so. I'll report any problems/success to this board.

   I've got to figure out my exhaust options and get a few more parts together but I should have this bike running within a month. I started this "project" last October with the simple idea of putting 836 pistons in. My big mistake(haha) was having the frame powdercoated, as every part that goes back on has had to be thoroughly cleaned, inpected, painted, or replaced. It won't be a "show bike" but it'll certainly be the "cleanest" CB750 I've owned.

[MRieck]

Sean
  The Megacycle lobes "shine up" after running. Remember that that cam is cast iron which is a little rough in regard to surface but is good in that it retains oil well. The gray finish is an anti friction coating that wears off quickly. Are you degreeing that cam in??

[scondon]

Thanks Mike. I was hoping that there would be some kind of "run in" with this cam   Unfortunately, I am not degreeing the cam. I do not have the experience or the tools? to do it. Considering the time and $ put into this project I will purchase parts, tools, and learn "on the fly" if this is a "must" for this cam.

[Sam Green Racing]

Hi Sean,

That cam has to be dialed in. If its a gnats dick out the motor will under perform.
You have spent a load of bucks on it, so do the job properly.
If your not sure, get somebody to do it for you.

Regards Sam.

[750deepsouth]

My megacycle 125-05 has smooth lobes, very smooth, smooth bearing surfaces too, but grey everywhere else :-)

I am using good used rocker arms. [although I'm not installing that cam for the moment]

Andy

[MRieck]

Hi Sean,

That cam has to be dialed in. If its a gnats dick out the motor will under perform.
You have spent a load of bucks on it, so do the job properly.
If your not sure, get somebody to do it for you.

Regards Sam.

I have to agree with Sam on this one. If you need a slotted cam sprocket let me know. I just sent one out to Sam a few weeks back as a matter of fact.

[scondon]

WooHoo! So all I need now is a slotted cam sprocket and a gnats dick for good measure

I'll give the local shop a call and see if they can't get me the sprocket. If not then yes, Mike, I could sure use one. I'll shoot ya an e-mail in a couple hours when I find out. Thanks.