DP Cams + Valve Adjustment Question...

[johnster]

I asked this question on TOB and pretty much know the answer, but being the paranoid SOB that I am I figured I'd ask again just to be sure... Well actually it's a variation of the original question:


    -So it's been 3000 miles since the DP cams were installed on my S4 (6000 miles of the bike now), which means the valve clearances had to be re-adjusted during installation, obviously.... This, in theory, means that I shouldn't have to get the valves checked/adjusted until 9000 miles, right??

    -WELL, my question is .... Seeing as how the valve action is more dramatic due to the bigger cam lobes, should I worry about the clearances being off sooner than they normally would??

    -Also (and this is sorta specific to the 916 engine), Would there be an increased risk that the rocker arms would flake due to the beefier cam lobes hitting the chrome harder?? 

   -Basically what I'm asking, is if I should bring it in sooner than 9000, or if the rocker arm/shim wear would be the same as if I were running stock cams??

Thanks in advance for any advice!!   

[Speeddog]

You should be good until 9k, IE, 6k miles on the cams.

I'm not sure *which* cams the DP ones are, Brad Black lists a whole bunch of cams here:
http://www.moto-one.com.au/performance/duccamspec.html

I suspect that the cams do open and close quicker, and that would increase the loads on the rockers.
So that would increase the chance of flaking.
It would also accelerate some of the the wear that pushes the clearances out of spec.

If you run your bike at high rpm a lot, then adjusting the valves earlier is sensible.
AFAIK, the flaking issue has been more severe on the 748, which tend to get turned at higher rpm.
In my opinion, it's high rpm usage that's the major factor.

[johnster]

Makes sense, Speeddog.....Thanks...

I've just been checking the oil filter for flakes, etc which would be where they end up anyway I would imagine...I don't run high RPM's or WOT too constantly (except for the occasional power-wheelie  ), so I'm just going to knock on wood, wait unitl the 9000 miles, and monitor the engine performance in the meantime....

**EDIT** The kit is the Full Termi/Spaghetti pipe/SPS Cam/Open Airbox/ECU setup...

-I still wish I could get to the bottom of that "airbox sneeze" issue though!!     It hasn't gotten worse though, which is a good thing...

[Speeddog]

OK, yeah, those have a bit more duration on the intakes, but quite a bit more lift for both intake and exhaust.

Neither Moto-One nor Doug Lofgren show the S4/ST4 intake on their cam curve charts, so can't really say whether the SPS intakes open and close harder, but it's likely they do.
SPS exhaust definitely opens harder than the Strada exhaust.
This does correspond with the exhaust note, an SPS cammed S4 is noticeably more 'snarly'.

Perhaps it would be prudent to get the valves done a bit more often than with the stock cams.
Maybe every 5k or so.
IMO, it depends more on how hard you use the engine, and that's really impossible to measure.

Ducs are a bit slow getting oil to the top end, so maybe wait a bit longer before getting high rpm.

[johnster]

This does correspond with the exhaust note, an SPS cammed S4 is noticeably more 'snarly'.

And it is...

At WOT the sound at the intake + exhaust completely changes from any other Monster I've heard.....MUCH more agressive than it did w/out the cams....Maybe I should make a video... 

-It almost sounds like it's running straight headers w/no cans, but only at WOT....The airbox is the same way....Idling, it sounds mostly like any other s4 with Termis....