Cams (2012)

acotrel · Jul 6, 2012

I know this is a Norton forum, but I thought you might like to see this, it's the 600cc Jawa outfit with the Neill Street motor:

http://www.youtube.com/watch?v=XoWlC8wzA7g

G Jensen · Jul 7, 2012

beng said:
Anyone ever use a Johnson cam for a Norton as here?:

http://www.johnsoncams.com/jc_n_cams.html

They have a nice selection and also look to have the best prices in the business.

I have a Johnson J360/264 cam in a hot rod 880 Commando. Johnson Cams was recommended to me by triple racer pal Jerry Liggett. At 2000 miles the cam appears to be holding up well and I like the way this (street) motor runs. To get the cam done I send my own standard cam to Johnson where it was welded and reground.
When I bought the Johnson cam, maybe 5 years ago, I talked to Keith Johnson on the phone several times. Keith was a very knowledgeable and gave me some great free advice. I recall that Keith is a proponent of 102 degree lobe centers, from the web data 102 degree centers seems to be a theme in Johnson’s own grinds.
Then for about the next 4 years there was a statement on the Johnson website that said that Johnson Cams was too busy to take on any work. I called Johnson Cams during the no new work years to see if they would do a cam for a triple for me and the guy on the phone, not Keith Johnson, said he wasn’t interested.
If you are considering a Johnson Cam I would call and find out what’s up and what kind of delivery you can expect.
GJ

Hobot · Jul 7, 2012

I too tried to contact Johnson a couple years ago and told to go away. Glad they are that busy yet making room for a mere one off Norton. I want to try a dual int/ext profile someday like the advantage them ole Triumphs have. Maybe 102' allows good overlap filling w/o too long duration peakiness?

Trying to bone up online on these cam topics I've come across two firm yet opposing Statements to ponder... Peel project forced me into #2 path.
1. The cam should be the first component selected then all the rest made to suit it.
2. The cam should be the last thing chosen after the basics, bore stroke CR and type intake and exhaust system plus the fuel and operation zone determined first.

marinatlas · Jul 7, 2012

Hi , few years ago , Keith made for me upon core supplied by me, one 360 and one 380 , it took him nearly a year to do them, but at the end after several phone call , I succed to get them , then Jim Schmidt arrived on the market with his cam/ followers and my Seeley went to full JS stuff, I had kept those two Johnson cams over me , and fit the 360 in my cafe racer with a std 30mm head, and Dunstall 10/1 pistons, much more tractable than the previous engine which was fitted with a 5S cam but oversize inlet valves and BSA (Norvil) cam followers into a 32mm ported head , the 380 is allready fitted in one engine on the bench with std pistons and a Combat head ........when everything will be finished , I could report , the differences between those mills.

acotrel · Jul 7, 2012

@Hobot
'1. The cam should be the first component selected then all the rest made to suit it.'

Always start with the gearbox. A good six speed box will permit you to use the most radical cams, and still have a bike which won't scare you shitless. If you haven't got the ratios, you cannot use an engine with the power band you get with the most radical cams. The beauty of the Norton is that it provides a lot of torque, and torque wins races. Whenever I think about improving the power output, I always think about ways of keeping the torque. The factory 750cc production racer had, I believe an 81mm stroke. When you do that, you are making it into a Triumph with the advantage of a squish band head. It is a move in a different direction. I raced my short stroke 500cc Triumph for about 12 years against a guy with a 650 Triumph. I was competitive against him, but he did it much easier. I've ridden his bike - it was set up to provide torque, and was never revved over 6,300 rpm. I was on Calder race way with it, and it out accelerated a good H2 Kawasaki with chambers.
My Triumph 500 was something that nobody should ever try t o ride. The motor was originally built in the 50s by an Irishman called Baldo Meli who worked for the Triumph factory. He got a twelfth place with it on the IOM in about 1948. It was a 650 stroked down to 63mm using a billet crank, and the cams were absurd. It had a 4 speed CR box, and I found it was impossible to ride around tight corners. If it dropped off the powerband in first gear, you were in between the devil and the deep blue sea. When it came on again it would immediately snap sideways.
The history of the bike in Oz was my mate had it in the fifties and took it to Bathurst. It bounced him off the armco at Skyline corner, and broke his arm and leg. He never told me about that, but when I bought the bike from somebody else, I found it was impossible to ride. I put a two into one exhaust on it and finally got reasonable lap times without the fear factor. I found the way to ride it was to drop the tyre pressures, soften the suspension, drop the gearing, and rev the tits off it. It's seen 10,500 RPM a few times - bastard of a motorcycle, but interesting and an education to own.

acotrel · Jul 7, 2012

About two into one exhausts. I read a comment on this thread that you guys are still debating the advantages of both types of exhaust. I found with my Triumph and a Laverda 750, that if the collector outlet is of smaller diameter than the total of the two header pipes, the result is pathetic. The pipe on my Seeley actually works very well, but I've never ridden it with separate pipes to compare the difference. However the bike is really fun to ride, even with the 4 speed CR box and high gearing, it spins up very quickly, and is hard to keep below 7,500 rpm. Incidentally I use a balance factor of 72%, when the motor idles the bike jumps up and down, but when it is revving it is beautiful.
I hope some of you get to buy youselves a Seeley copy frame , and build a bike like mine. I built it in 1978, and because I didn't believe in it, didn't race it until 2003. But it is a bloody good thing and I love it. I'm just surprised that such an awful motor can go so hard.

acotrel · Jul 10, 2012

I am still interested in whether anyone else has ideas about the cam timing to use with a two into one exhaust. It stands to reason that it must be different to compensate for the different impulse and extraction effects. As far as 'valve clash is concerned, I usually put the head on with a bit of kid's plasticine across the valve pockets. Rotate the motor, then take the plasticine out and cut it across with a razor blade. Then you can actually see how much clearance you have as the piston passes top dead centre.

comnoz · Feb 4, 2014

Does anyone have a Megacycle 560-00 cam I could borrow to make a graph. I lost some of my files from several years ago when my backup died and that was one I have lost.
I am still interested in any other unusual cams to graph also. Thanks, Jim

bwolfie · Feb 5, 2014

I'll look at what I have here. I know I have 2 megacycles, but they are over at the shop.

ILLF8ED · Feb 5, 2014

nortriubuell said:
comnoz said:

nortriubuell said:

Wow ... though mostly over my head, great thread ya started here Jim !!! Just curious, I've got a 1971 750 motor, and the cam is marked "SS" :shock: Is this a hi performance Norton OEM cam ??? Perhaps i should use it in the 850 motor I'm building; opinions from all are invited ...

Click to expand...

That sounds like a 2S- Combat cam. You can confirm that by measuring one intake and one exhaust lobe. They would be quite a bit different. The 2S cam is the only factory cam with considerably more lift on the intake than the exhaust. Jim

Click to expand...

Well, your EXACTLY correct Jim. (still don't understand why Norton marked it "SS" ... but then "call" it a ... "2S" what kind of "pizzaro world" logic is that ??? :?

Anyway, it measures 1.263 and other is 1.261" for the the inner lobes; and measures 1.219" and 1.218" for the outer lobes. So the inner lobes are a bit larger as you say. Yes, quite different indeed.

It still puzzles me though, any thoughts on why Norton marked it "SS" ... but then call it a "2S" ??? :? BTW, this cam was in a 1974 850 motor I stripped :shock:

Why they marked is "SS" is a mystery, but calling it 2S is to distiguish from the "SS" camshaft from the Dominator which the combat cam is not. The Dominator cam was not marked "SS", so when you see this it is a combat camshaft.

KHK · Feb 11, 2014

I have a mega cycle 56020 SSS spare cam that had some damage on one lobe, kind of an oddball, I run it on my street norton, seems to come alive above 4500. Any interest Jim ?

comnoz · Feb 11, 2014

KHK said:
I have a mega cycle 56020 SSS spare cam that had some damage on one lobe, kind of an oddball, I run it on my street norton, seems to come alive above 4500. Any interest Jim ?

Yes, I would like to get that profile. That is one I have not seen. Jim

worntorn · Feb 11, 2014

I hope everyone here realizes that at some point we will need to extract DNA from Jim for future cloning.

Glen

cjandme · Feb 12, 2014

worntorn said:
I hope everyone here realizes that at some point we will need to extract DNA from Jim for future cloning.

Glen[/quote

+1 ......you guys are funny this forum is a great distraction for me right now ....hey, while you're at it , I think you need to get some of Ludwig's DNA too :shock:

worntorn · Feb 12, 2014

How about using DNA from both to create the ultimate Norton Guy?
Is Genetic Engineering wrong when it improves a Norton?

Gle

acotrel · Feb 12, 2014

When I was racing regularly years ago I was searching for more torque from my short stroke 500cc Triumph. I tried various configuration exhaust systems and changed the cam timings from meeting to meeting to try and optimize. I started with separate pipes with 4 inch megaphones which made the bike deadly, and ended up with a two into one with a large diameter tail pipe with took about 1000 RPM off the top, however I was then able to get respectable lap times, and outride many other competitors without giving myself ulcers. In those days, I usually rode my fifties 500cc Triton in Allpowers C grade, which was always the charge of the light brigade. The competition had Z900 Kawasakis with aftermarket pipes and Yoshimura cams, Also H2 Kawsakis with expansion chambers. The best ride I ever had was when I dropped the gearing right down, softened the suspension and dropped the tyre pressures. I led all of them for almost a full lap of Winton, however three of them out powered me down a straight and got into a corner too fast, so I had to stand my bike up to miss them when they chickened out (drum brake when they all had discs ), and ran off.

By the time I had built my Seeley 850, historic racing was the go, so it all became pointless.

comnoz · Feb 10, 2015

After my 4th axis drive failed I have only been able to map a cam the hard way. I finally got the wiring and programming done to get the mapping software working again. Here is a video of how I do it.

And if anyone has a cam and they don't know what it is or have a cam that is not in the database and they would like to share -you can send them to me and I will post the results here and provide return shipping. Jim

[video]http://youtu.be/s1iOguANcmw[/video]

PS The lifter grinding sounds rough because I was not really doing any grinding and the motor was just running slowly.

SquareHead · Feb 10, 2015

Jim,

Probably a stupid question (and I just had 2 pints of Guinness!), but do you only want cams that are Norton compatible? I assume that's the case, but if you are looking for other motorcycle cams, I may have a few laying around.

Thanks, and it's always enlightening to follow your threads. You have taught me quite a bit just by reading your threads.

Regards,

Chris

comnoz · Feb 10, 2015

SquareHead said:
Jim,

Probably a stupid question (and I just had 2 pints of Guinness!), but do you only want cams that are Norton compatible? I assume that's the case, but if you are looking for other motorcycle cams, I may have a few laying around.

Thanks, and it's always enlightening to follow your threads. You have taught me quite a bit just by reading your threads.

Regards,

Chris

Just Nortons for the forum.

I can pretty much map any cam but since my hardware is pretty much built for Norton cams the setup would take a lot more time. Jim

Hobot · Feb 10, 2015

What is split lobe point? Don't ya have to do each lobe to know for sure?

Cams (2012)

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