You'll have to get the complete grind numbers for the 293 and 101. Actually, I'll bet the good folks at web cams can explain it better than most of us can.

My guess is that the 293 provides more low-end torque and less on the top-end, but without seeing the grind numbers there is no way to know. Unless you want more top-end, I wouldthink that the stock cams should suffice...they offer the best compromise.

 

EDIT: 2/12/2008 - Updated below

 

Looks like the the 293 has a higher lift and shorter duration/less overlapwhich translates to increased compression/combustion efficiency at lower RPMs (better low end torque), but will suffer at higher rpm where higher flow fromlonger duration and more overlap is needed.

The 101 has lower lift but longer duration which tells me it's more efficient at higher RPM (grinded more for flow).

I am just a novice at grind numbers, soI'm sure there is somebody lurking who can explain it better or maybe even prove me to be an idiot, but that's how I interpret the graphs/numbers.

I have heard that thegood folks atWebcams can explain the charts in great detail.

 

What you said is generaly right on.
Look at the numbers in this case, though, and you'll see that they are so close, +/- a few degrees, and in the case of lift, +.010", I'm not sure you'd see any difference on the bike.
Under ideal conditions, and with a perfect tune, on a dyno, one would probably work slightly better than the other.
I wouldn't want to guess which one.
Many factors have to be considered. Each motor, and application will have its own idiosyncrasies, and as a result will react in a different way to different grinds.
IMO, either of these cams will work well.
When I saw the durations (at .050") being similar, the first thing I looked at was the advertised durations.
The profile with its duration at .050" closest to its advertised duration will ussually be the better performing one, due to its quicker (steeper) ramp angle.
Being that this is a bucket/shim style lobe, and symmetrical, open/close rates are the same on either side, and not a factor of consideration.
In this case, they are practically the same.
This makes the judgement based entirely on numbers that much easier.
When two grinds are so similar, you really have to start splitting hairs to decide on which one might be better.
In this case, I'm sure either would work fine.
Does anybody have the stock numbers for comparison?

 

Just looking for a second opinion and trying to educate myself more. If and when I go with a cam, I'll probably go with the
#293 grind. For my riding, I'm less interested in top end power than I am in low end grunt.

Here is a table with the numbers: EDIT: 2/12/2008 - Updated table below


Still missing the valve lift number for the stock cam.

Here's what a person from Web Cam said:

"For a Trail riding application I woulddefiantlygo with the #293. If you look at the specs, it has a short lift high duration on it for good acceleration and torque. You have the big bore kit on it as well as a full exhaust system so that profile should run great." (NOTE: She had dislexia when she wrote this, it should say "high lift, short duration" instead)

I agree the numbers for the #101 and #293 seem to be really close, but both are quite different from stock.

 

Its really not possible to say how different they are from stock, not having the stock numbers.
Don't even try to use advertised duration to compare, as there is no datum point from where they were taken.
Note that even though the advertisednumbers indicate greater duration (who knows why?), both perf. grindsappear to beadvanced ~ 5 degrees from stock.
The problem is, that there is no datum point from where those measurements were taken, either.
It would not be out of the ordinary to increase duration, then close up intake centerline to bring back some bottom end. The result being a broader torque curve. Again, without all the numbers, its not possible to say.
With that chart, comparison from stock to the perf. grinds is not possible.

 

When I spoke with Web Cam before building my motor, they suggested the 101 unless I wanted to use stronger valve springs. Steve Story, the owner, also said that the 101 was a reasonably good midrange cam, but made good high RPM power. This is where I think those of us with the 101 grind have yet to see the full benifit. Once one of you gearheads works out the ignition timing problem, I think we will see a whole new animal here as our engines won't be so retarded above 8000 RPM. I'd love to know for sure.

Bill Dragoo
Norman, Oklahoma
KLX 331

 

A couple of updates. The table above has been changed, the timing numbers are at 0.050" of lift. Webcams confirmed that the timing numbers for stock are at 0.050" too. Webcams also gave the stock lift to be 0.325"

Another quote: "I would recommend springs for this application because of the high lift, you don't want to go in to coil bind. (When the spring is fully compressed, you need to have a total of .045 clearence, which is at least .015 clearence between 3 of the coils.)"

This confirms what Bill said, alternate valve springs will be needed if going to the #293 grind. Their spring kit with retainers is $225

 

.325" for lift makes sense, but I don't buy the stock duration at 260/264 at .050".
For an OEM cam, with this type of motor, that would be practically unheard of.
It must bea mistake.

 

Ok, I'll run those stock numbers past them again. Unfortunately, the timing and duration numbers from the service manual are not referenced to a datum. The numbers from the service manual are in the table above and here:

Duration: 260/264
Exhaust: 61 BBDC / 19 ATDC
Intake: 22 BTDC / 62 ABDC

At what lift do you suspect these were taken?