S&S Roller Rockers for Milwaukee Eight

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Here’s the one we’ve been waiting for since the Milwaukee Eight’s 4-valve heads were announced, except it’s not the one that most people expected: it is not a new rocker arm with an adjuster on one of the forks to allow riders to sync the valve clearances between each pair of valves. I’ll let them explain what they are:

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Big lift cams can open up the high revving potential of the Milwaukee Eight power-plant, but they can also add stress to the stock valve-train geometry.

Valve thrust and valve-train wear in big lift cam applications drove the S&S engineers to design stronger, more durable components that will help you get the most out of your M8 and first on the list was Forged Roller Rocker arms. Their new rockers are stronger, more durable, and designed to be easier on the rest of your top end.

Oil routing is updated and is now sprayed directly on the valve springs – helping cool and lubricate these hard working parts – and they are compatible with stock or most CNC ported heads. They feature a 1.640 Ratio and are capable of handling a 0.650” valve lift, and are as essential mod for increasing the longevity of your valve-train components – particularly with cams running .550 or greater lift.

Making big reliable power has always been what S&S does best and the new Forged Roller Rockers are a solid addition to their M8 performance parts line!

So, not adjustable rocker? Good luck with that if you want to put a roller on the tip.

Harley-Davidson engineers were absolutely clear about adjustable rockers when we spoke to them – the engineers, not the accountants – face-to-face at the Milwaukee Eight launch. They tried them and the consistent thing they observed with an adjuster on one tip is that it goes out of adjustment, whereas a fixed one doesn’t. If one valve seat should go out of adjustment, that would be a bigger problem but the obvious solution is to cut the valve seats as pairs.

S&S obviously believe that there are more important things to worry about when uprating these engines and have done what they do best: looked at what could be improved within the motor, and then improved it. They haven’t ruled out the possibility of doing something in the future if the need arises – it’s still early days for the Milwaukee Eight – but they haven’t seen a need for it yet.

Harley, of course, have released an adjustable set of rocker arms under the Screamin’ Eagle banner, but that’s probably to shut some of the more vociferous critics up. A couple of people are complaining about tappet noise at the rockers, and that will have turned into hundreds by the time those threads have been shared, but be reassured that this is the rocker arm taking up slack on the looser of two valves because the conventional hydraulic follower will adjust until it takes up the slack on the tighter of the two. It is exactly the same noise you’d get if an adjustable tappet goes out of adjustment and will be less than the sound of solid cam followers on a cold engine.

And it’s not necessarily going to be down to rocker arm adjustment: it could be anything that messes with the rocker shaft’s alignment in the head or even a dodgy rocker.

These stronger S&S items will at least remove any doubt relating to the quality of the rocker – whether you’re fitting high lift cams or not – and as you’ll be removing the rocker shaft to fit them you might want to think about the more precise stud and screw replacement for the stock bolt that holds the rocker shaft in place. We covered that both in New Products and Boz’s tech in AmV99: a coarse thread where it goes into the aluminium – and held by red Loctite – and a fine precision thread for holding the shaft in place for future servicing.

S&S 900-1084 Forged Roller Rocker Arms for M8 Models $524.95
S&S 900-1013 Heavy Duty Stud kit for M8 Rocker shaft $99.95
www.sscycle.com

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