What cam do you have and why?

It seemed time for a lively discussion...

I'd like to ask the collective here: "What cam are you running and why?" and "What do you like about it?"

Lets see if we can avoid arguing shall we? There is no "right or wrong / good or bad" there are only personal opinions and experiences.

I'm aiming this question at those who have deliberately chosen a specific cam in their builds.

For starters, I'll share mine:

I'm running a JS1 cw lightweight cam followers in my '74 850. My cam followers and cam follower tunnel in the barrel were all scored beyond use, so the lightweight followers running in their own bronze blocks made perfect sense to me. I am a fan of lightweight valve train mods anyway, as this was a big focus of my old sponsor and mentor, Dave Degens.

I needed a cam to compliment the higher CR I'm running (10.5:1) and bigger carbs (35mm FCRs) and I have subsequently had the RH10 head given the 'full Comnoz' treatment. I thought long and hard about the JS1 and JS2 and eventually decided on the JS1.

I like the way it delivers its power, its still very tractable at low revs but definitely 'comes alive' at 3,500+ and it pulls very strong to over 7,000 (although I try not to go above 7,000 too often). There is no real comparison to how it was before with stock cam, stock CR and a single Mikuni. It is a completely different animal altogether, more torque, far more power and smoother.

I still think about alternatives though, I still think I could easily go a little more radical, but don't want to spoil what I have. Its a conundrum many of us have I guess!

Please share your own thoughts / preferences...

Fast Eddie said:

It seemed time for a lively discussion...
<snip>
Lets see if we can avoid arguing shall we? There is no "right or wrong / good or bad" there are only personal opinions and experiences.

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Those 2 statements are somewhat at odds with each other !!
Ones arguing is anothers correcting the record, or pointing out there is another point of view.
Sums up this forums foibles and 'lively discussions' completely.

And since I didn't choose any cam other than stock, my opinion is probably worth zip here then ?!

But, not entirely off track, I will tell a tale of someone I went to see, who had fitted a concentric carb to an old Model 7. He said it was "running great", and I was looking forward to seeing it in action.
It was coughing and spluttering and chugging black smoke.
"Running great, isn't it."

Hmmm, how would that show up on the forum here in a discussion...
Opinions are worth what you paid for them ?

Have the stock cam now cuz the bottom has never been apart.

But, have a Webcam 312a with 4" radius lifters in the mail from JimC for use with my new FA head. Cuz I want a nice hotly streetable bike that is all about the midrange.

gortnipper said:

Have the stock cam now cuz the bottom has never been apart.

But, have a Webcam 312a with 4" radius lifters in the mail from JimC for use with my new FA head. Cuz I want a nice hotly streetable bike that is all about the midrange.

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IF I understand correctly... a WC 312a with radiused lifters has very close lift, duration, and timing to the JS1. So should be a great combo with your FA head IMHO.

When I was racing mine, I started with a 4S. Then I went to an Axtell #3 ( AKA the Axtel 5S ). To be honest I couldn't tell any difference.

I have run the 4s in two motors now , std rebuilt 850 and 920 with a mild head job & 35mm FCR's .
I liked it the first time & I like it even more the second time .

I'm running a PW3 cam with everything else pretty stock,with a single VM34 Mikuni and, of course, my first production Fullauto Technologies head (No 2) with untouched ports and standard valve sizes. I was told that the cam would be somewhat wasted using a single Mikuni and I had thoughts of going to JS's twin Keihin CR33s after I ran the motor in. I probably still will but, some 4000 miles on, I'm really impressed with the combo. I run a 22 tooth front sprocket so the gearing is taller than stock.

It still pulls well from down low but with a meaty mid range that makes it feel very strong. Certainly stronger at low revs and through the mid range than a stocker. In top gear it picks up revs noticeably better than before. Top end? Dunno, because I don't really go there. It's got everything I need at lower revs. It will be interesting to put the Keihins on, just to see the difference.

Very very relaxed and satisfying performance, and this is a big and, 64 MPG (Imperial)! The most I've ever wrung out of a Commando. Back in the seventies, with a Combat cam on my MK2 850 and standard Amals, I used to get low 40s. With a big power step at 4500 revs. The current motor has no power step. It pulls from nothing.

There you go, Nigel. My seat of the pants impression. No dyno chart. Sorry.

I'm running the stock cam in my '73 850. I did a complete rebuild on the motor in 2010 and wasn't at all interested in performance. I owned a BMW S100RR at the time so any extra HP that I coaxed out of the Norton would have paled compared to what the Beemer put out. I wanted a mellow reliable bike that I didn't have to worry about. It works well and doesn't pack any surprises. I bought and restored this bike more as a mobile art project rather than a hot rodded 40+ year old racer. The bike is fairly stock and makes me smile ever time I look at it. When I sit in the garage enjoying a cold adult beverage my eyes always focus on the Norton. Sorry HD Roadking, you're a traveling tool. The other rolling stock in the garage are all designed with form following function. The Norton is all about form, form, and yes, still more form. I love this bike.

I've always run the stock cams in my Nortons (18 to-date), with the 2 exceptions of the alloy tank monoshocker I built and sold in 2010, and my Dreer prototype engine (all the parts still on the shelf waiting to be built up); those two both use the Megacycle 560-00 with radiused cam followers.

The '72 Roadster I'm totally rebuilding turned out to be a Combat, and the cam is stamped "SS". I am rebuilding the engine to original Combat spec's to experience all that fun first hand, hopefully by next summer.
Bill

put a Megacycle 5600 cam in my 850 as the best all around power curve upon the recommendation of my builder Jim Mosher of Performance Indian, Pecos, NM

Fast Eddie said:

IF I understand correctly... a WC 312a with radiused lifters has very close lift, duration, and timing to the JS1. So should be a great combo with your FA head IMHO.

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Correction - A Webcam 312a running flat lifters is similar to a JS1. Jim

Stock cam because I've never had reason to switch it. It gives me all that I want.

I am a Sunday rider and I really like the stock cam. Couple that to an 850 motor and you've got something very usable.

After Replacing a heavily planed stock head with a Fullauto one the bike would then only perform at high revs.
A check revealed a full on race cam so replaced that too, a PW3 seemed like a good idea.
Quite happy with how it now goes.

Stock cam for me as well. Rebuilt engine to mostly stock specs. I wanted reliability. It runs good the way it is and will hopefully stay together for a long time.
As Eskasteve says, it makes me smile and the Fatboy sits in the corner.

Fast Eddie said:

Lets see if we can avoid arguing shall we?

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Yer right :lol:

Do you guys actually believe that when a racer sells you a copy of his good race cam, the timings he specifies will suit your motor - give best performance ? If you are using a two into one pipe which gives more back pressure, surely the exhaust opening point of the cam should be different ? Perhaps if you use a vernier sprocket on the cam and try advancing and retarding it in 3 degree steps, you might discover something about power delivery ? I still use a near standard 850 cam in my 850 motor, however it is advanced by 12 degrees to suit the two into one pipe. The motor pulls strongly from 4000 RPM and goes straight through the top. (of course the methanol fuel helps a lot) . I have stayed away from race cams and strictly limit my revs to 7000 RPM max. I haven't even polished my rocker gear - which is probably the first thing I would do in a normal race motor.

When I first built the 850 motor in about 1978, I figured that whatever cam was in it, Mr Norton would still build the bike to comply with American And British noise and pollution laws and provide power characteristics suitable for commuting. So how could the cam possibly be timed to give best power in a standard 850 Commando ? Even in the 1959 Triumph Bonneville, the exhaust cam was the Tiger 110 grind, except for the Thruxton Bonneville which had the E3134 race cam grind on the exhaust as well as the inlet. With early unit construction Triumphs, it was possible to buy the E3134 grind with the points extension. With that fitted to a standard Bonneville and changing nothing else, the bike was much quicker.

I like Jim Schmidt's go-fast bits, particularly the longer rods and light pistons. However the BSA type cam followers seem to be a pit pointless to me because once you start revving a commando engine over 7000 RPM, you are into a much more expensive game, and do you really need to go there ? The strength of the commando engine lies in it's torque characteristic, NOT top end power. To my mind the 6 speed gearbox is a better investment than the billet crank and thicker cases.

Fast Eddie said:

Lets see if we can avoid arguing shall we?

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toppy said:

Yer right :lol:

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Jim just corrected fasteddy on the cam number.
We can see why 'arguing' isn't going to be allowed here... :mrgreen:

P.S. Where are the dyno charts to prove these "cams are great" stories ?