Opinions on 4 5/8 89" stock case camshaft welcome, I currently run a DME 581

DM581 - 26 42 56 12 248 248 38 98 112 105 0.58 0.58 0.227 0.144

Roadking, 3.37 gearing, 2 teeth off trans pulley, Rineharts TD, I ride 2 up and a 6'3" 270 lb donut eater and your wasting energy to type "lose weight" 20 lbs is beer, I also ride solo with hard riding lighter bikes (Evo's, stroked Shovels) and nothing better than them having to keep looking at my mug in their mirror while accelerating.

My stock heads are going to a head specialist for porting and is going to set my compression for flat tops & DM581, interested on hearing thoughts on a optimal camshaft for my riding style before any work is done and I'm to picky to take a chance on a W6H noise not able to be tamed.

 

Just out of curiousity, whos going to port your heads? also why stay with a flat top piston? just curious.

 

Talk to your head porter. He should know how his heads flow, that along with the other info will allow him to make an informed decision. Be sure to set your squish right as it will help prevent detonation and make the bike run right. Because he chose to go with flat-top pistons he must know the little secret about them. Hope this helps.

 

John Sachs, he runs a Wiseco 1200 Sportster flat top piston in his 4 5/8 89" ridiculous numbers aerocharged engines, they protrude 012-015" on deck height, he recommended the piston set up when he does my heads.

Did alot of background on John and reeks of performance knowledge, highly regarded by other engine builders and not too big for the small guys like me. I have followed his leads and he had no problem with helping me set up my engine but just looking for opinions about cams, he felt my DM581 will work fine but I have always tried to learn more by asking questions.

Any opinion helps Miacycles, thanks

 

John Sachs definetly knows the secret of the flat top pistons!

 

You called it early, somewhere you have sat and stared at a Harley engine for hours or layed awake at night to make this statement. I'll leave this stuff to you guys, I'll keep buiding my diesels.

 

The advantage as explained to me in school is pretty simple.With a pop top the incoming air charge and flame front has to travel over the hump in pop tops where as with a flat top its a straight shot,in laymens turms..Im no engineer and wont claim to be,just passing on what was taught to me....but back to the topic at hand,follow youre builders recomendation.

 

From my days of mudracing (572 injected nitrous Hemi) I deeply studied engine efficiency and the flat tops provide lighter rotating weight, better flame travel and no hot spots that can cause detonation expecially with nitrous. Hemi's domed piston was a disadvantage until a blower was bolted on or a whole bunch of nitrous to pack the cylinders.

The same piston theory should work with a Harley, I guess that is why Mr Sachs produces some very efficient engines. His non-aerocharged engines produce large HP to cubic inch ratio and the aerocharged 89" was @ 168 hp (off memory)

I am defintly following his advice, he wanted my stock heads over the SE heads so the SE's were sold (tough one) and I bought into his knowledge.

I guess the cam question was answered in my first post