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S&S 551 gear driven cams

8K views 18 replies 10 participants last post by  prodrag1320 
#1 ·
I was wanting to install the new easy start S&S 551G cams, and I had a question.
S&S states that they are easy start cams to help your starter last longer, but our new Road Glides already have some type of system in place that acts as a compression release.
So do I need to look at another cam set that is not easy start or not? I like the new 551G because it's good for low end torque up to 4000 rpm, which is perfect. I want that heavy bike to get off its ass sooner than later.

Thanks
Loner
 
#3 ·
I may be wrong but when at the HD dealer looking at the new bikes I did not see any compression releases installed on the touring models with the 103 engine and I was looking to see if the new bikes are coming with ACR's because I am putting ACR's on my new heads. The 103 engine has a 9:6to1 compression ratio which is not high enough compression to require compression releases. I don't think that the easy start cams would be necessary but I haven't heard anything bad about them so if that's the cam you want then give them a try.
 
#4 ·
All the current(from at least 2011-up) 103" motors come with ACRs installed from the factory. They are not visible, as they are installed down in the center of the head rather than out by the spark plug like the older aftermarket versions, and they vent internally into the exhaust port. If you have them you can hear them if you listen carefully when starting the bike.

Here's a couple pics of where they're at:
http://www.danvanceracing.com/id124.html

Ok, back to the original question.
yes, EZE start cams are redundant if you have the ACRs from the factory.
 
#5 ·
My question to the OP, you're getting gear drive cams, have you checked the run out to make sure your crank is in spec? If not you'll be in for a rude awakening miles down the road. Also the 103s do come with a compression release which is automatic, (somebody chime in if I'm wrong), which means after so many revolutions of the motor they close wether or not the motor starts. The S&S is a centrifical release which means the motor has to reach a certain rpm before they stop working, so they will work until the motor starts which is why they are so easy on a starter.
 
#7 ·
ACR's

Hey Guys,
Thanks for the response. I'm still learing this bike, and I now know that any 103ci from HD has the ACR. Redundancy is a good thing.

I'm going with the S&S 551G EZ start cams. I'm thinking with those cams, my RSD intake, Rinehart Extreme true duals 4", and Power Vision custom map, that 820 lbs beast may win some races against those jaskass buddies of mine with lighter bikes.
Look out.... here I come...............

Thanks guys
 
#8 ·
Depends on what kind of bikes your buddies have, also don't forget about checking the run out. I'm also curious, why are you going with gear drive instead of chain?
 
#9 ·
I put gear driven cams in another bike of mine and just loved the quick response. I also like the fact that you remove the chain shoes. Also, the bike idles different and sounds different with gear driven. I know when a bike has gear driven cams in it, and I just say that's the sound of HP.
It's just my preference. I know chain driven are very good too, it's just I don't like chain lag.
 
G
#16 ·
im a big fan of geardrive cams,but your wrong here too,if you can hear a difference,your gears are too tight (a gear whine),or too loose (ticking),not only do you need to check run out,but gear back lash must also be checked to make sure oversized or undersized gears are not needed.please explain "chain lag" too
 
#11 ·
You don't have to check runout at all if you go with the 551G cams. They are bolt in which means you don't have to do a thing to ur engine. Now if you go with higher lift cams you have to check valve clearance and you have to install stronger valve springs. I'm not going to get into that crap! Besides from what I'm seeing about those S&S 551G cams, they are PERFECT for getting a heavy bike moving fast. They call it a torque cam. Torque gets you there quick and then HP makes you go fast.
BTW with these 551G cams they say you can use your stock push rods, but I HIGHLY recommend that you spend the $190 extra dollars and get the Screaming Eagle adjustable push rods.
 
G
#15 ·
please dont tell me your working on anyone but your own bike.pinion run-out MUST be checked on ALL gear drive applications and has NOTHING to do with cam lift,its got to do with the outer gears eating each other up.another example of why you really need to check out who`s working on your bike
 
#12 · (Edited)
You absolutely DO need to check run out before installing gear driven cams on any twin cam. We have been installing them for years, and we check run out on every twin cam, regardless of year or displacement. We do a ton of 510's, and now 509's, and since some years are so prone to walk, we keep 255's in stock in case we tear down and the bikes do not except the gear drives.

 
#14 ·
Thanks Nick-O and roadwolf for confirming what I previously posted. Loner, the run out has nothing to do with the lift, you must be thinking about valve springs or something. With gear drive the tolerance has to be a whole lot closer than with a chain, gears aren't as forgiving.
 
#18 ·
GD cams

I have questions for the 3 experienced engine builders posting to this thread. I recently bought a 2001 RG w/gear driven cams, I must assume that runout was checked at the time of install, but can or does it change over time ?

I spent my childhood around street rods and drag racing and always loved the sound of a Jackson gear drive set-up, but based on your statements here, I have to assume that if the noise is that noticeable maybe they are not set up correctly ?

Mine in my bike make just a little noise, nobody notices except me, should I be concerned ?

Thanks guys
 
G
#19 ·
sure it can change,thats how the lower ends get out of spec to begin with.if the bike gets abused (holeshots,downshifting hard,ect)if yous is making a little noise i propley wouldt sweat it,but pulling the cams out & checking run-out isnt a big deal either
 
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