5 hp is not possible without changing hard parts.  You might be able to gain 2 hp with higher flow muff/intake/jets.  When running at 80+ mph the motor sounds like it's going to fly apart but it won't.  If it bothers you, use a pair of earplugs or headphones and ride on.  The vibrations aren't bad at all IMO.

This sort of discussion makes me wonder if Dave couldn't create a cottage industry for modified Kawasaki front pulleys, just as Verslagen did with his tensioners. I do note that the front pulley mod requires very good tooling when trimming the width down and I am willing to bet that most forum members don't have the skills, the lathe and the tooling to do it. There are times when I look for sixth gear.

jcstokes wrote on 01/28/16 at 19:47:17:

exactly precisely yes
the ONLY thing that kept me from trying the Kaw pulley was the fear that I'd buy the thing, and the machinist I used would screw it up
no way I'd try to do it even if I had a lathe, which I don't, and I highly doubt more than 1% of S40 riders do, either
I'd even have been willing to buy the pulley up front so Dave wouldn't of had to be out of pocket for the part

If you are serious, here you go...  

http://www.ebay.com/itm/Kawasaki-EN450A-EN-450-A-454LTD-Front-Drive-Pulley-19...

 It's cheap enough, but you need someone to machine it for you, $100 at least.   ( unless you have some good dirt on them )

jcstokes wrote on 01/28/16 at 19:47:17:


Well I am slowly working on it.  The Kawasaki Ninja engine I took apart has transmission shafts with the same size and spline....so I can use those shafts to make mandrels to hold the pulley for machining.  I am a lathe NOOB, and I have never been able to make nice clean cuts on the lathe.  Even when cutting soft PVC or brass it would leave a funny pattern on everything I cut.  No matter how I sharpened the cutting bits, what speed or material I was cutting....the pattern showed up.  If I changed the rpm or the cutting speed - the only thing that changed was the shape of the pattern...it looked like "Tweed" or "Herringbone"  I first thought maybe the shaft bearing where worn out - but they felt fine and new ones would be over $ 600!  I started to suspect something was wrong with the motor, as it was very loud even when disconnected from the lathe....and once you cut the power to the motor it coasted very smoothly to a stop.  I took it to a motor shop and he replaced the bearings and a few parts, and the motor was a bit less noisy and the pattern got smaller.  The motor was a Baldor - but I am sure it was not the original motor, and the Forward/Reverse switch was not the original (I suspect it was a 3 phase motor originally).  I started looking at the wiring.....I couldn't really make sense of what they did, so I used the diagram on the switch and the motor and started from scratch - and I do believe that fixed it and it finally works properly.  You can see the cuts on the left side that were made before the work on the motor....and the right side is a cut I made after changing the wiring.


I have never cut really hard metal on my lathe - and I likely will need to get some carbide cutters to make this work.  (Any lathe experts are welcome to come over and give me a lesson).

I would not plan on me getting this service up and running for a little while.


 

MeeLee wrote on 01/29/16 at 13:58:32:


My $ 600 estimate is if you were to also buy the rear pulley, and modify the Kawasaki pulley to fit the Suzuki hub, and pay someone to machine your sprocket hub as well......the cost to do both pulleys.

So....what year is your bike?

MeeLee wrote on 01/29/16 at 14:36:50:

How you gonna' afford the $1,000 in mods you are talkin' about?...

I say,.. just get it, and ride it...  the difference between 65mph and 75mph, is 10 or 15 minutes per fill-up...
So,.. just leave 10 minutes earlier...

The metal on those pulleys is HAAAAAARRRD!...