I currently have my engine apart to replace the cases and balance the crank... And while doing this I am considering Roller Rockers. So yesterday I went to the shop to get everything together and took a good look at my rockers. To my surprise I found 2 of them were galled but luckily the valve stems were ok... It was on the front intake and the rear exhaust. Why just those 2 and not all 4? I don't have the answer to that but will research it more to hopefully find out... If anyone that has used the S&S 900-4098A rockers and has the instructional sheets I would appreciate it if you could post them up... The reason I ask is because S&S also offers a 900-4098FA and a 900-4098RA roller rocker that designates a location of front intake and rear exhaust and front exhaust and rear intake. It believe it has to do with the geometry of the valve train.
So everything I'm reading about Roller Rockers and when to use them makes a lot of sense. Any lift over .580 especially if your going to use stronger springs.. By the way, these rocker that I currently have in the bike were replaced approximately 24K miles ago when i was chasing down lifter noise.. I guess i should have installed the Roller Rockers then...
Last edited by 98hotrodfatboy; 02-17-2019 at 08:03 AM.
The reason I ask is because S&S also offers a 900-4098FA and a 900-4098RA roller rocker that designates a location of front intake and rear exhaust and front exhaust and rear intake. It believe it has to do with the geometry of the valve train.
900-4098A is a set (includes both front and rear)
900-4098FA is a front exhaust/rear Intake (each)
900-4098RA is a rear exhaust/front Intake (each)
I've been running with the Crane Roller Tip Rocker Arms (4-1015) for years in my EVO.
900-4098A is a set (includes both front and rear)
900-4098FA is a front exhaust/rear Intake (each)
900-4098RA is a rear exhaust/front Intake (each)
That's what I thought but was not quite sure.. So it's safe to say that the geometry between the 2 is different, same as the designation in part numbers of the OEM rockers
.. thanks..
This is discussed at length over and over.
To narrow dwn the answer and skip rocker geometry, lift, cams, and a zillion other things, its the wear on the guides and stems..
Rollers are little wheels and convert the action to a more straight push dwn rather than the lateral force combined with the push.
They help against valve side loading when you are running components that change your valvetrain geometry suck as high lift cams, oversized valves/lengths, and decked heads
This is discussed at length over and over.
To narrow dwn the answer and skip rocker geometry, lift, cams, and a zillion other things, its the wear on the guides and stems..
Rollers are little wheels and convert the action to a more straight push dwn rather than the lateral force combined with the push.
No ****.....
Originally Posted by misfitJason
Nailed it^
They help against valve side loading when you are running components that change your valvetrain geometry suck as high lift cams, oversized valves/lengths, and decked heads
Fully aware of their function, thank you.. I was making a statement not a question but thanks..
My only question is about the orientation of the rockers and why just my front intake and rear exhaust were affected and not the other 2... That's all...
98 Hotrod
Cant read your mind..
AFAIK according to smarter people then I, the HD geometry is fked from day one.
To get "over center" and be retreating at the 1/2 mark is prolly the goal so as to be even distribution.
There are people that will fix the issue and add roller tips to stock rockers so it is as purrfect as it can be with correct ratio.
02-17-2019, 08:02 AM
Why Roller Rockers....
