Topic: Cam choice - I require superior wisdom!

[srbakker]

Hey all,

I'm plotting the course on my engine build and I could use the infinite wisdom of the HiPo crew (/ego stroke  ).

I have a set of NOS 812 ART forged pistons with Hastings rings going into my K5 750.  The head will be ported, probably by MRieck, with new guides, springs, valves and retainers.  I was planning to leave the rods alone, although if you all think it's necessary I might consider an upgrade to the APE or cyclex super rods.  Of course, everything will get stripped down and measured for tolerances as I plan to bead blast the cases anyway.

Incoming flow will be through stock carbs (although I do have a set of Mikuni VM26 with a cb750 manifold I might try to use too) and outgoing flow through a Kerker 4-1 with a Dynoman 2" baffle.

I'm a bit puzzled over cam choice.  I want a tractable street ride but I'm definitely not above winding it out to 9-10k at least once per ride.  It doesn't seem lke there are a lot of options - one suggestion I'd heard was the old Megacycle 285 grind, but these now seem to be unobtainium, and too bloody expensive to boot.  The most common choice seems to be the Webcam 41 or 41a grind, but I also see that Dynoman now has a replica Kenny Harmon D grind they call their "cafe racer grind" (holding in vomit now) which is slightly lower lift with longer duration.

Yeesh.  Someone just pick me a cam!

But seriously, I'm learning this stuff as I go.  I would greatly appreciate any thoughts on cam choice or on my proposed build. 

Cheers,
Scott

[Sam Green Racing]

Scott, best bang for the buck is the Megacycle 125-65/60. It gives a great spread of power but falls off at about 8900rpm. So providing you don't go silly, stock rods are fine.

Sam.

[srbakker]

Can anyone justify the fact that it's double the price of the other cams?  Is it really that much better?

[Sam Green Racing]

It's not the cam that's better but the way it's made, it's said that hard welded cams are better than billet but saying that, I've never had a problem with billet cams.
Megacycle always charged more for hard welded cams but they no longer do billet cams for the CB750, besides that, I couldn't find any prices on their site.
Dynoman offers billet and hard welded cams at the same price.
His DP295 cam offers similar performance to the Megacycle 125-60 at just $225. I have run this cam and in my mind is just as good Scott.

Sam.

[srbakker]

Ah ha!  Thanks Sam - that's the sort of info I was looking for.  Much appreciated!

[MRieck]

Megacycle SOHC hardweld cams retail for 349.00

[754]

APE has cams for less than 3 bills I believe.. Hard to recommend cams cuz in the end you probably be wanting hotter anyway.. once you get a taste..
 Tried a few hundred times to blow up stock rods, if you are not roadrascing, they will hold up for most.. besides cases and cylinders are still cheap...

[Sam Green Racing]

Frank, my fellow Moderator Mark Linder (who we have not seen for some time) said time and time again that it was safe to rev them to 1300rpm, then one day.......

Sam.

[754]

 They can and will blow up!
 But we got two 836s here in town that have logged at least 500 runs in the 1/8 and 1/4 mile, and seen extensive street use and held up fine. I havent seen anyone revving past 12K. but the OP of this thread says he wants to keep it under 10 k.. The only expensive part blowing up an 836 with stock head is the sleeves and pistons.. motors are cheap.. just saying..