Back in October, I posted a request for loaner cams.  There isn’t much information on the cams that fit the LS650.  I wanted to measure and record the timing data on the available LS650 cams, and also plot the cam curves in ten-degree increments for easy comparison.  I was able to come up with five cams to measure.

I had previously posted some timing checks on the stock cam and a DR650 cam (1995 model year), but I measured the timing data at the valve.  The standard practice is to take timing data on the lobe at a predetermined lift.  The SAE checks timing at .006” lobe lift, and various cam manufacturers check at either .020”, .040”, or .050” lobe lift.  The Harley crowd checks at .053” lobe lift.  After sifting through all sorts of literature, I arrived at the conclusion that most of the experts like .050”.  I decided to check cam timing at .020”, .040” and .050” and tabulate that data.  That way it will be easy to compare one of our LS650 cams to any other cam that has timing data at one of those three lifts. All the timing data I tabulate in this post is taken at the lobe, not the valve.

In addition to the timing data, I took valve lift data in ten-degree increments and plotted curves to display valve lift in relation to crankshaft position.  The curves allow an easy way to quickly compare one cam to another.  I also measured maximum valve lift and TDC valve lift.  I used the maximum valve lift point to determine lobe centerline, and used that information to calculate lobe separation angle (LSA).  All of the data collected for the cam curves, maximum valve lift, and TDC valve lift, was taken at the valve, not the lobe.

I tried my best on all the tables and graphs to identify where the readings were taken.  This was a pretty big job for me and there’s a possibility that I flubbed up a reading or two.  If you are going through this data, and you unearth what appears to be a screw up, please call it out and I will do my best to get it corrected.  That could be tricky because all the loaner cams have been returned.

I measured the stock cam, the Web 466, the Web Stage 1, the 1995 DR650, and the Web Stage 3.
 
The stock cam is obviously a low performance item, and the Web 466 is only slightly more aggressive.

The Stage 1 and the DR650 are almost identical, with the DR cam owning a slight edge.  It has more TDC lift and overlap, which should give it a nice mid-range sweet spot.  One possible problem with the DR cam is the intake closing point.  At 34° ABC it is the earliest closing point for any of the five cams measured.  That increases the effective compression stroke and could result in detonation if you increase compression with a pop top piston.  The DR cam also does not incorporate oiling holes in the lobes.  I am currently running the DR cam and am not experiencing any issues with detonation or oiling.  I inspect the lobes periodically and will post any problems I experience on those lines.

11/1/23 I ultimately learned that the oil holes in the cam lobes provide lubrication for the left-hand main bearing and balancer bearing.  I had two main bearing failures before I figured this out.  DO NOT RUN THE DR CAM WITHOUT DRILLING THE OIL HOLES IN THE LOBES AND ENLARGING THE CENTER HOLE ON THE RIGHT-HAND SIDE OF THE CAM. DBM

The stage 3 is the most aggressive but looks like it will offer good drivability.  It really doesn’t have any more duration than the DR or Stage 1, has minimal overlap, and relatively low TDC lift.  However, I personally do not consider the Stage 3 a bolt-in cam because of its maximum lift (.393” intake).  With only .430” available travel between the valve spring retainer and the guide seal, the .393” intake lift leaves only .037” clearance between the retainer and seal when the valve is fully open.  You generally want a margin of .060”, so as a minimum, the head should be checked to make sure you won’t have an interference problem with the Stage 3 cam.  I know that some members are running that cam with no problems, but there are manufacturing tolerances to consider.  The consequences of a collision between the retainer and guide are grim at best.  If you don’t plan on doing a proper setup, use the Stage 3 at your own peril.

I respectfully invite comments and discussion on this post.  Testimonials to the cam you are running now, or have run in the past, would be great.  Comments on any problems you have experienced with any of these cams, or others not contained herein, will help all of us to avoid serious issues on our projects.  Please share information about setup, springs, retainers, clearance, interference, etc.  It goes without saying that we are all anxious to hear about performance.  How does your cam perform?  Did you have to increase your compression ratio to compensate for late intake closing event?  Fuel octane? Failures?  Loss of low-end performance?  Freeway performance?  Hard starting?  Detonation? It’s all good.

Also, if you are aware of any other camshafts that fit the LS650, please share that info.  Even if the cam isn't a bolt in, there may be some members that are willing to perform the necessary mods to accomodate the cam.  

Knowledge is power.

Best regards, Mike

Here is the stock valve lift data.

Here is the Web 466 valve lift data.

Here is the graph of the stock exhaust lobe vs the Web 466.

Here is the Stage 1 valve lift data.

Here is the graph of the Stage 1 exhaust vs stock.

Here is the DR650 valve  lift data.