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#833047 12/12/20 6:59 pm
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Hi, does anyone have experience with megacycles 542x2 cam? I've got a number of 68-473 cams to pick from for my motor build but thinking about picking up one of these. What's the effective difference with this versus stock. What does "improved mid range" mean functionally wise?
I'm not looking for racey. A little more pep isn't bad but overall having a solid, daily around town with longer weekend trips is the goal. Being able to run at 70+ all day is more important to me than going fast from stop light to stop light.
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They why bother changing from the stock cam?

If you want to try something, buy another camshaft pinion and broach several key ways in it. Then learn how to dial a cam in with a dial gauge and you’ll get pretty close to what the mega cycle cam is giving you. After all it is supposed to be identical to the original cam... just retarded a few degrees.

Ps. With the mega cycle cam you’ll also need to have your followers ground to 3/4” radius (stock is 1.25”)

I’m using the X12 cam... it’s ok but I’ve used other cams (less expensive) that pack more punch.


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68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (now rebuilt)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

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The standard 473 cam is adequate. It's quite a 'sporty' item anyway.

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I tend to agree with the above comments but to answer your question, I have some experience with the x-2 on my race bikes. First, I used standard tappets and if you are getting a new cam, have Mega reface them for you. At first, I made the mistake of setting the cam a couple of degrees retarded because 'that's what you do with the 473'. It sucked! Reset a couple of degrees advanced. Result, a small amount more power in mid and upper range. A couple of horses. They say stock springs are ok but if you are going to the trouble get new ones. Ed V. sells good springs that are not 'race springs'. Real 'race springs' require a lot of maintenance with valve lash. So, if you are building a street bike you don't 'need' a different cam but get new springs and set to spec and check to make sure cam is set to spec on all 4 lobes. However, if you want to make sure everything is tip-top then get the x-2, springs, etc. and then spend a few bucks on dyno time for a good tune. Hope this is helpful. PM if you want more info. PRT

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Since this is a discussion on A65 cams......My A10 Super Roocket has the stock 357 cam in very nice shape. I have read it's very similar to the A65 473 ?...I believe the stock intake lobe center for both these cams is 105 degrees? Do any of you think advancing the cam to about 100 degress would be better for a road bike? This engine has about 7.75 static compression...
I do have a lot of experience with Triumph cam timing changes so I might assume the A10 would be similar..


79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
"I don't know what the world may need
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Originally Posted by Allan G
They why bother changing from the stock cam?

If you want to try something, buy another camshaft pinion and broach several key ways in it. Then learn how to dial a cam in with a dial gauge and you’ll get pretty close to what the mega cycle cam is giving you. After all it is supposed to be identical to the original cam... just retarded a few degrees.

Ps. With the mega cycle cam you’ll also need to have your followers ground to 3/4” radius (stock is 1.25”)

I’m using the X12 cam... it’s ok but I’ve used other cams (less expensive) that pack more punch.


I was considering buying a new stock cam instead of putting a used one in, just about everything else in this motor is new. There's a new megacycles cam on eBay that's about half the cost that got me thinking about it but your right, I'm past the days of taking it out to the track on weekends so stock cam it is
Great feedback thank you

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Tony, My book shows 98.5 and 110.5 for both the 473 and the 357. I don't think you could go wrong by setting as close to that as you can..Or maybe a couple of degrees towards straight up. PRT

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Originally Posted by NickL
The standard 473 cam is adequate. It's quite a 'sporty' item anyway.

Agree. I just haven't known anyone that's done a cam upgrade on the a65 so was curious what the experience has been. Like I mentioned to Allen G there's one on eBay for the cost of a new stock so seeing if its worth the trouble. Seeing as I'm more tame these days the sticking with stock seems the way to go..

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Originally Posted by pushrod tom
I tend to agree with the above comments but to answer your question, I have some experience with the x-2 on my race bikes. First, I used standard tappets and if you are getting a new cam, have Mega reface them for you. At first, I made the mistake of setting the cam a couple of degrees retarded because 'that's what you do with the 473'. It sucked! Reset a couple of degrees advanced. Result, a small amount more power in mid and upper range. A couple of horses. They say stock springs are ok but if you are going to the trouble get new ones. Ed V. sells good springs that are not 'race springs'. Real 'race springs' require a lot of maintenance with valve lash. So, if you are building a street bike you don't 'need' a different cam but get new springs and set to spec and check to make sure cam is set to spec on all 4 lobes. However, if you want to make sure everything is tip-top then get the x-2, springs, etc. and then spend a few bucks on dyno time for a good tune. Hope this is helpful. PM if you want more info. PRT


Great info. I'm gonna stick with the stock. My flat track days are over (for now 😉) so tempting though...

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Originally Posted by pushrod tom
Tony, My book shows 98.5 and 110.5 for both the 473 and the 357. I don't think you could go wrong by setting as close to that as you can..Or maybe a couple of degrees towards straight up. PRT
Thanks Tom....I will check it just to be sure... 110 degrees on the exhaust is quite a bit, Must be some reason for it..


79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
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Think I'll drive to find a place, to be surly"
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A good old 473, which most are works fine a new one will soon look the same. You can see if it has wear but I've not seen it.


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Originally Posted by Mark Parker
A good old 473, which most are works fine a new one will soon look the same. You can see if it has wear but I've not seen it.

I have 2x 473 cams which I’ve dialed up, one is still spot on with the numbers. The other I think someone has tried cleaning up with a stone as one inlet gives incorrect numbers, when I’ve calculated the LCA using lift angles at 0.080” lift I find that one side is a few degrees different.


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68’ A65 Lightning “clubman”
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Haven't posted in quite some time. Former name was blimey-bill, but was probably linked to my old email addy. Anyhoo, I've been making some progress with the A10 crank (taking my time, lol) for my A65. I have a set of the E&V A70 (10.5:1 CR) pistons and I'm wondering if a longer duration cam would be beneficial in lowering the cylinder pressure a little. The Megacycle X2 specs out with a pretty good increase in duration and a little bump with the lift. This will be strictly a street ridden bike. Bore and stroke will be 76mm X 84mm. I'm not chasing after high RPM horsepower or anything radical. I have a bunch of dual carb heads, both small port and big port. All of them have stock size intake valves. Also wondering if fans of the small port head prefer the later style big intake valves. Cheers!

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Got the big valves on one of my small port heads with a multi angle cut seat… made no benefit over the standard 38mm valve.

I wouldn’t waste my money on the X2 carb either. The spec is the same as the stock cam, apart from the key way is timed a few degrees retarded. I doubt the cylinder pressure would lower by much. A full race cam would do though. If you can get one of the SRM race cams it will do what you want. Sadly they don’t seem to show stock of any. From memory the timing isn’t too different from the sifton 380 cam.

With the small port head the arm race cam worked really well on my 680cc. The best setup I have had.


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71’ A65 823 Thunderbolt (now rebuilt)
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Just spotted this and off the top of my head here is something to consider. Also consider that this is a SWAG. You are building a pretty big motor so I think bigger all around would be beneficial. Big ports. Big valves. X2 cam with std radius lifters set straight up or a degree or 2 advanced. Ed V has good springs and he can advise installed ht. Check your pushrod length and, maybe, get some chrome moly ones. Do not use aftermarket aluminum ones. Carbs no smaller than 32's. Don't forget the exhaust system. This can make or break your build. Tough to be specific here as we are not sure what your application may be. Do not expect to use pump gas! Cheers, PRT from N. J.

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Ben just got nice C/molly pushrods from Ed V I got a G/box mainshaft support plate for the firebird. Spending money is better making the thing strong than replacing a very good cam. Why I am fitting MAP steel rods soon as well.

The camshaft isn't a big restrictor on the motor, nor is the exhaust port, but the stock inlet port is. Hopefully the numbers Tom might get with the Hornet might show this up. But generally it just makes it nicer and more responsive.

Our pump gas is 98 it's fine with 11-1 with B44 pistons, Ben has the angled EdV forged A65 ones .040" and we will be trying to get as much compression as we can from them in the 671. Though I'm of two minds about that if high domes restrict breathing as the Firebird is 9-1 and if the race thing goes as well it should good for power and easy to ride.

Last edited by Mark Parker; 01/10/22 10:21 pm.

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Pardon my ignorance, but what's a SWAG?

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That Is a ScientificWildAssGuess. Dick, where are you in NJ? I'm in Westfield.

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Fair Lawn. BTW: my name is actually Bill, lol.

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For pushrods you can also try Smith Brothers in Oregon. They are popular with the drag and stock car people...Set of moly is about 50 bucks... you do need to tell them the length and end type and size.


79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
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Think I'll drive to find a place, to be surly"
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So as it turns out I had a bit of a brain fart. I dusted off the A70 pistons that I bought from Ed-V and they're not the 10.5:1 angle dome type. I started this project way back when, but other projects got in the way so it took quite a while to make progress with the A10 crank. Anyhow, the pistons I have are 9:1 so I'm just gonna stick with the stock BSA cam. I do appreciate all the replies I got though if that's any consolation.

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You do know with a 9-1 dome on the shorter A70 piston travelling further you get higher compression because of the extra displacement?

9-1 turns into around 10-1.

Last edited by Mark Parker; Yesterday at 07:48 AM.

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You can still add some compression by removing the base gasket and probably removing a couple of thou from the top of the barrel. Most heads have been decked anyway again increasing compression.

I wouldn't let the change of compression stop me using a certain cam. it will still improve perfomance.


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71’ A65 823 Thunderbolt (now rebuilt)
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I would look at skimming the cylinder or a thinner base gasket if you really want higher compression. On my A65 stroked to 750cc, I shaved the cylinder down to match the top of the pistons (T140 with massaged valve pockets) which gave me 14:1 ratio using standard base and head gaskets. Also running a MegaCycle X8 camshaft. I would run the cam you originally choose as others have mentioned, you will gain some performance even with the 9:1 pistons.

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