best cam for 920

baz · Mar 16, 2015

what would be the best cam to use in a fast road going 920cc engine with an rh4 head ,a stock cam or a 4s? the reason for asking is i already have these cams in stock along with all parts including big bore barrel/pistons to build another commando engine ,,,,,,,,,,,cheers baz

Hobot · Mar 16, 2015

Engine comp ratio should determine the happiest breather, octane and timing permitting. I'd guess if ya like the short shifting spurts of torque up to good passing speeds then standard but if wanting to keep on going too fast to be passed >>> I'd be restless regardless till I tried them both of course. Oh yeah more over lapped cam implies less starting effort.

cash · Mar 18, 2015

More cc requires more time to get in, I'd go for the 4S

Cash

bwolfie · Mar 18, 2015

You could always install a quick change bearing kit and try them both.
I have made and sold them, have them on all my bikes.
Takes less than 30 minutes to swap cams.

baz · Mar 18, 2015

bwolfie said:
You could always install a quick change bearing kit and try them both.
I have made and sold them, have them on all my bikes.
Takes less than 30 minutes to swap cams.

that looks good i have heard of these but not seen one how much do you sell them for ? are the needle rollers fed by splash? do the needles run directly on the cam? cheers baz

bwolfie · Mar 18, 2015

Splash oiling, Rollers work on scrolled and non scrolled cams.

I was getting $150 for them, I also include a bearing for the other end.

Requires machining to fit both.

Unfortunately I do not have any in stock, and won't be able to make any more for a few months.

Reggie · Mar 19, 2015

cash wrote;

More cc requires more time to get in, I'd go for the 4S

When I was building my 920 that is basically what Steve Maney said to me (regarding camshafts).

cjandme · Mar 19, 2015

Reggie said:
cash wrote;

More cc requires more time to get in, I'd go for the 4S

Click to expand...

When I was building my 920 that is basically what Steve Maney said to me (regarding camshafts).

Thank you both for posting that info, good to know guys.

I really like this forum because of information exchange like this. Thanks again, Cj

Fast Eddie · Mar 19, 2015

Reggie said:
cash wrote;

More cc requires more time to get in, I'd go for the 4S

Click to expand...

When I was building my 920 that is basically what Steve Maney said to me (regarding camshafts).

Am I right in thinking that Steves cam is basically the same as the 4S ?

Reggie · Mar 19, 2015

On this thread ;http://www.accessnorton.com/bob-920-special-666-t3279-45.html?hilit=steve%20maney%20camshaft

BobV wrote;

Regarding the cam/followers. Consensus in the heart of Norvil land (I live only a few miles from the luscious Les Emery), is that the Maney cam is essentially a 4S and there is no need to radius the followers for this cam - something to do with lack of quietening ramp, although I don't want to open a can of worms here.

Seeley920 then wrote;

Funny that, Les Emery can't even give proper details about the so called "norvil" cams that he sells himself!! try ringing him about set up. Ok if everything is bog standard and by the original factory manual, not so good as soon as you deviate from this!!

So is Steve's cam based on a 4S or not? I'm not sure? Is it folklore from Mr. Emery or does somebody know better?
Incidently, I run a PW3 on my 920.

Matchless · Mar 19, 2015

Steve told me his cam is a modified 4s form. I'm using a PW3 in my 920. Goes pretty well but I haven't tried anything else.

Chris · Mar 20, 2015

Hi

yep Steves cam is very close to a 4s. I love this cam (4s) & run it on most of my bikes, it just seems to give the best drive/feel. Basically what I think the Commando should go like. The PW3 didnt seem to make a lot of difference on the 750 sprint bike but it has nice midrange & top end & has ended up in the 850. On the big engine Dave Watson used a 7s The bike (960) is stunning. We used a 7s on the 750 & it was a complete flop.
Again the old saying runs true. Everything has to be matched to get the best out of an engine.

Chris

baz · Mar 20, 2015

i think i will run it with the 4s cam to start with

dero · Mar 22, 2015

I have a 4S in my 920 , has done quite a few miles now , I am very happy with it .

B+Bogus · Mar 24, 2015

Here's a Steve Maney cam next to a 3S from an old Proddy Racer spec motor

I didn't apply any profiling analysis to my measurements, but they both have the same lift and if the profiles are different it isn't by much.

best cam for 920

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