Here we see the filler blend at the exhaust guide boss.

I mentioned that the 1.3” pipe is not going to complement the enlarged port outlet.  You need a 1.5” ID or larger pipe to take advantage of the enlarged port.  When I tested the enlarged port with a 1.3” adapter, the flow didn’t improve much.  I was compelled to switch to a larger adapter.  That worked great.  This is the enlarged 1.5” ID adapter I used.

The void is formed by the juncture of the diverging port bevel and the converging pipe inlet.  I’m sure you are familiar with the bevel.

The intent of the insert is to provides a flow path with a uniform cross section from the 1.3” port outlet to the actual 1.27” pipe inlet.  I came up with an insert and my tests show some good results.  When used with a stock head and a stock exhaust header pipe, the 1.3” insert increased flow by 4.2 %.  I will be doing a separate post with all the details on the insert.  Here is a look at what I came up with.

When the stock header was installed on the stock head, flow was reduced by 10%.  

When the stock header was installed on the ported HammerHead, flow fell by 27%.  

For these comparisons, I used 28” H2O test pressure.  

I don’t think it’s a good approach to run the 1.27” ID header on a souped up head.  It will probably work a little better than stock, but there are other ways to get that kind of power aside from porting the head.  Porting the head and slapping on the stock header pipe seems to defeat the purpose of the port work.  All that port work choked off by that teeny-weeny stock header.  My goodness!

I think this test came out well.  The flow improvements are substantial, and I think we can all benefit from the results.  I will keep you informed regarding my progress on the good head, along with the results of my epoxy and filler putty tests.  Of course, the special insert post is forthcoming.  I think it's a simple and cheap improvement.

As usual, I invite your comments.  What is your real-world experience with porting the Savage head?  Anybody out there got any concrete data (like a dyno run, or some technically reasonable performance measurement)?  If you performed similar port mods, did you have to make any significant adjustments to carburetion or ignition timing?  Any problems with detonation, fuel octane, etc.?  How’s the reliability?  How’s the clutch holding up?

Once again, I must thank Fast650 for his generous donation (the HammerHead).  It has been invaluable.  He also played an important role in evaluating my test data and keeping me on track.  This has been a very long and difficult project, but well worth the effort.

Knowledge is power.

Best regards, Mike

Mike have you ever considered reducing the DD-2, that exists between point C & D ?

I'm not arguing with your results, but could there possibly be a reason for those dipsey-dos??  

Could those actually be a feature the enginers put in for some sort of scavaging or back pressure effect??  

I'm thinking along the lines of "if it were all about airflow then you could argue that we shouldn't run pipes at all".   I believe Suzuki's engineers are probably a pretty smart group and either put those there for a reason or were mad as hell they had to leave them there at all.