Air Intake

Tim Brown

New Member
Hi, I’m new here but have read many threads for a few years now. I have an 07 K-9 (carb) v&h big radius 2-2 setup 9500 miles on it. 31/78 jets
Just had the ehc rip kit put in cause it had the wires plus unit and died. Also have thunder heart adjustable ignition module. Looking to do some upgrades and asking for advice on cam size and air intake currently looking at reaper 594 vs s&s 600
And the arlen ness monster sucker vs s&s dual runner. Any info suggestions warnings would be greatly appreciated
Thanks ride safe
 

1 B.M.F.

Well-Known Member
Hi, I’m new here but have read many threads for a few years now. I have an 07 K-9 (carb) v&h big radius 2-2 setup 9500 miles on it. 31/78 jets
Just had the ehc rip kit put in cause it had the wires plus unit and died. Also have thunder heart adjustable ignition module. Looking to do some upgrades and asking for advice on cam size and air intake currently looking at reaper 594 vs s&s 600
And the arlen ness monster sucker vs s&s dual runner. Any info suggestions warnings would be greatly appreciated
Thanks ride safe
Tim I don’t know if you have done an introduction yet I haven’t looked but you will get more reply’s on your own thread. Welcome from Texas. I would go with the S&S 600 cam and the S&S dual runner. They look better to me. Plus it keeps everything S&S. Either way you go you will have to re-jet the carb. Just to keep everything smooth. Good luck. Go to introductions and tell a little about you and your bike and post pictures. Everyone likes pictures. Welcome
 

mleach72

Well-Known Member
Tim, both of those cams are very close in all specs, so I would expect them to be nearly identical in performance. The big issue with these cams is that the intake valve closing is a bit late for the 117's stock 9.6:1 compression. This takes a toll on low and mid range torque. A cam like the 585 is going to be a better performer through the entire rpm range. Sure, in a stock motor, the 600 will probably produce 2-3 more hp, but this won't show up on a dyno until about 5k rpm. You will likely need to change springs for the 600. The 585 is a straight bolt-in cam. The 585's earlier closing intake valve produces higher cylinder pressure which makes the bike pull hard all the way through the rpm range.

A good way to illustrate this is the Big Boyz Heads compression calculator. A great all-around performing engine has a cold cranking pressure (CCP) in the neighborhood of 180. This engine will have a great torque curve and won't be a pain to start. A ccp that is a lot higher will have potential detonation problems and will be hell on the starter, even with compression releases. A ccp that is a lot lower will have soft bottom end and will likely not get very good fuel mileage.

The first two pictures are comparing the 600 and 585. The last picture is the 600 after the jugs have been shaved .040". This gets the static compression up over 10:1, which is where the 600 performs at its best.

The two ac's you mentioned are both excellent. Any ac using a K&N type filter (cloth element that requires oil) will move a lot of air and still maintain excellent filtering capabilities.

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Mr. Wright

Knows some things
:agree:, I ride with a couple of guys that both have K9's. one is running the 585 cam, and the other is running a 650 cam, with over $4000 in engine work. On the track, they are just mil-seconds apart.
The 117 is actually a de milled 124. If you want to go to a 600 cam, go the whole way and change out the crank and rods, to make it back to a 124. Otherwise the 585 cam is the best way to wake up this engine.
 

Twistedspoke100

05 Mastiff
:agree:, I ride with a couple of guys that both have K9's. one is running the 585 cam, and the other is running a 650 cam, with over $4000 in engine work. On the track, they are just mil-seconds apart.
The 117 is actually a de milled 124. If you want to go to a 600 cam, go the whole way and change out the crank and rods, to make it back to a 124. Otherwise the 585 cam is the best way to wake up this engine.
Do the jugs need to be changed as well? And are the pistons the same?
 
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