Wow!  Lots of activity here.  This is getting interesting.

Regarding Lancer's comment "Keep in mind that the Stage 3 cam is in the low range for cams duration wise, and the lift is nowhere near even the stock DR cam".  

I recently finished mapping out a Stage 3 that Dave loaned me.  The Stage 3 cam has the following max lift numbers, .393" Intake, .376" Exhaust.  The stock 1995 DR 650 cam has the following max lift numbers, .365" Intake, .364" Exhaust.  So the Stage 3 actually has a bit more lift than a stock DR650 cam.

Regarding DR springs vs LS springs, the parts fiche shows that the DR & LS use identical springs, part #12920-37402.  The retainers are also identical, part #12931-4500.

Lancer, I really appreciate your input regarding your spring setup with the Stage 3 cam.  It tells us a lot about how forgiving the valve train is.  With that cam having faster ramps and higher lift, combined with a relatively close proximity between retainer & guide seal at max lift, the fact that you can wring its guts out on a regular basis sets us all at ease.  Looks like that puppy can take it.  Also, great info on the Mac header.  It pretty much tells the story on header ID.  Seems to me that the book is closed on that topic.  All the formulas, tables, charts etc. indicate the ID of choice should be between 1.5 to 1.625", and it seems to me that we have testimonials that support that.


Regarding Dave's comment, " it just doesn't pull all as hard when you approach the upper limit of the rpm range.  The bike reaches 80 mph easily, 90 comes with a bit more work....100 takes a good while and there really isn't much left".

As you increase speed, the wind resistance increases exponentially, its not a linear function.  So its natural for your acceleration rate to decline dramatically as you exceed 70 or 80 mph.  Your on top of one of the most aerodynamically challenged vehicles ever designed (an unfaired motorcycle).  It's like trying to push a sheet of plywood through the air.  In addition, it's a single cylinder.  Multi cylinder engines have shorter periods of time between power impulses, so multi cylinder engines have a much easier time plowing through the wind.  That single cylinder takes one step forward on the power stroke, and three steps backward on exhaust, intake & compression strokes.


As far as your compression is concerned, as I recall you reported on another thread that you have somewhere on the order of 195 psi cranking pressure.  I'd say that you need to stick with premium fuel.  The Stage 3 cam closes the intake valve at 38 degrees ABDC, the stock cam closes the intake at 40 degrees ABDC (those numbers were measured at .050" lobe lift).  So the Stage 3 cam actually closes the intake sooner than the stock cam, which in turn increases your effective compression stroke by 2 degrees.  Add in the pop top Wiseco and your in premium fuel territory.  No sort of vacuum retard feature to pull timing out under load and you really have no choice.  Too risky to run 87 or even 89 octane.  The Stage 1 that you were previously running closed the intake at 40 degrees ABDC, so with that cam, your effective compression stroke was identical to stock.  I agree with Fast650, the cylinder pressure is a key factor in fuel selection, but we should also consider other factors like ignition timing and quench clearance.  The LS650 has effectively no quench since the piston doesn't get close to the cylinder head at TDC, and the timing really can't be adjusted too readily.  Maybe that's why the advance curve is so darned shallow. When I did my timing test the first thing that struck me was how high I had to rev the engine to achieve full advance.  I don't have a tach but that puppy was really singin by the time it stopped advancing.  Maybe the OEM simply dogged out the curve to avoid any detonation problems.  Pretty easy solution, set the compression ratio in limbo land (how low can you go), and advance timing at a snail's pace.  Some more low hanging fruit?  We shall see.


Stay tuned for a cam comparo.  I have to remove the DR650 cam to do a better map and plot a curve.  Then I can finish it up.  The reason I posted the head data first was because I wanted to be able to see if the cams are all bolt-in.  Seems they are.  With all the cams plotted out on a bell curve, we can then move on to trying to improve cylinder head flow, and figuring out what improvements can be made to flow at lower lifts & higher lifts.  That will make selecting a camshaft for the combination a bit easier, and also help in deciding what head mods will work best for a particular riding style & budget.

I was going through some of my old Harley notes and came across a printout of a dynamic compression ratio calculator I used.  It's really cool and provides a lot of interesting info.  You will need the rod length, bore, stroke, combustion chamber volume, intake valve closing point, calculated static compression, etc.

Try it out.    http://www.rbracing-rsr.com/comprAdvHD.htm

Here's a look at what the calculator provides.

 

How long does it take to figure out
Very limited potential?

ohiomoto wrote on 11/26/18 at 20:32:51:


Not sure if he left because we were too tuff on him - or he learned that the Savage is not going to get him any big HP numbers or low ET's.  He hasn't posted anything in 5 months - but did log onto the site 3 weeks ago.  Every couple of years we get a new member who is going to turn the Savage world upside down and turn it into a big HP power monster....then reality sets in.  DragBikeMike is going about it in a far more methodical/schooled investigation........and may well find a few HP that has never been available previously.  "MORE POWER TO YOU"!

 

Dave wrote on 11/27/18 at 04:59:56:
---------------------------------
I agree, more power to you DragBikeMike!

I'm not one to judge how someone goes about it, I enjoy seeing what people come up with.  It's all good in my book and long is it's not my checkbook.  

Ruttly wrote on 11/27/18 at 10:24:05:


I am with you - both in reliability and durability.

Being able to make more power by increasing efficiency and breathing ability should not cause things to wear out or break.  I am pretty satisfied with the increase I got from the Wiseco, cam, carb, light flywheel and mild porting changes - especially since most of my riding is done at 1/2 throttle or less.  I wear my tires out in the curves.....not by accerating hard down the straight sections.

I am not opposed to finding out how things could be improved beyond where we currently are.....is there some HP that has been elusive?    

Oh yeah there is still H/P on the table , but is it worth the money and at this point is where we trade H/P for rock solid dependability ! My bike is fast and I haven't even done the stage 3 cam yet and I may not. So ask yourself what you are willing to do about it.