Topic: high performance street/strip/track motor... advice???

[MCRider]

hey MC,

i have a K6, so i have the lighter rotor.  can you help enlighten me on why i've read some people saying there's issues with running a lightened crank on a decent running 836 kit?  i think i've made the decision to build the motor properly when i get some funds...  what do they lighten on a rotor, and do you have to run a kick only when you do this? 

after enough consultation with Mreick, i've decided to go with the big bore kit, so i'm looking for some smooth power that's good for an all day cruise if needed!!  i don't think i'm going to go with new rods, just use some F rod ends from Mreick and have the K rods shot peened and cryo'd.  so any input is appreciated! 

sorry to partially thread jack justin, but i figured this could help everyone!  oh ya, did you get those pics of my motor?

As Big Jay has said, I know of no issues running a lightened crank on an 836 or any size motor, stock or 1000+cc. Lot of personal experience there.

As BJ says, running the lighter OEM later rotor and all's well re electric start etc.

But even if you had the earlier heavy rotor, lightening it does not interfere with the electric start.

[MCRider]

one other thing...  what about the welded valve covers?  do they make a difference with a build like this??

I think they look trick as heck. THe original CRs had them. I've had personal experience where I would have benefited from having one. High RPMs with heavy duty springs and big bump cams make the cam holders flex all over the place. this affects valve timing and high performance running, and accelerates valve gear wear. The bolts in the reinforced covers are screwed down to touch the cam holders and force them down against the head, precluding any flex.

In the worse situation, they can flex to where they spit out the little Orings that hold the oil pressure to the cam, the cam seizes in one of the cam holders and twists in half. Now you have a perfectly fine 325cc twin, except it weighs a ton. 

Now I've heard MRieck and others say that cam profiles and spring technology have improved to where these reinforced covers are no longer needed. I am not smart enough to say yay or nay and their rep is on the line. (Apologies if MRieck did not say this. I heard it somewhere.)

So that brings us back to looks. THey just look mean IMO.