I installed one of Dave’s 25T pulleys back in September of 2022.  It was a significant change.  Rather than machine the back side of the pulley, Dave suggested that I could shorten the pulley spacer.  I thought that might be a good approach, so I agreed.  The installation was easy but there were a few small details to iron out.  Seems like a good candidate for a report.

Previously, Dave would machine the backside of the pulley to achieve correct belt alignment and to allow the splines on the output shaft to engage the lock washer.  Should be able to shorten the spacer and achieve the same outcome.

I had to trim the spacer exactly .200”.  That should place the centerline of the new pulley in the same location as the stock pulley.  If you use this method, make sure to remove the material from the side of the spacer without notches.  The notches are oil passages.  Remove them and the output shaft will not receive any oil.

When I installed the spacer and tried to fit up the pulley, the pulley would not go all the way home.  The sharp corners on the female splines bottomed out in the roots of the male splines.  A minor setback.

That was easy to fix.  Just machine a 35° chamfer on the female splines in the pulley.  The face of the pulley must bear hard against the spacer.  The chamfer eliminates the spline interference and allows the pulley to go all the way home.

The splines on the output shaft must protrude a bit for the lock washer to engage.

The pully cover boss on the engine case interferes with the pulley, so you have to file the aluminum boss.

Dave provides two stainless steel button head screws.  Replace the stock 6mm bolts with these screws to make sure the pulley and/or belt doesn’t rub.  One screw goes on the output shaft seal retainer as shown here.

I had plenty of room on the swingarm, no need to file out the axle slots.  I was done with the entire job in a couple of hours.
 
I was running a Dunlop 140/90 rear tire.  When combined with the 25-tooth pulley the final drive ratio was just under 14% taller.  My cruising rpm dropped about 500.  It made a big difference.  Where I used to run at 4500 rpm on the freeway, now I cruise at 4000.

At first, I didn’t care for it.  It really dogged out my acceleration.  The bike still had plenty of steam, but certainly didn’t yank like it did with the 23-tooth pulley and 140/80 rear tire.  Over time, it grew on me.  I have come to appreciate the reduced rpm.  I initially installed it on my 94mm flat-top engine and now am running it on my 97mm pop-top engine with a four-speed trans.  They're plenty fast.

My fuel economy was not affected.

I know this seems a bit haywire.  The larger pulley and rear tire make the speedo and odo read a lot lower.  The stock Savage speedo is optimistic.  It indicates high.  It’s my understanding that it’s about 10% high.  That’s how the factory delivered it, and that’s what I suspect most Savage riders are using.  Up to this point, all my mileage and economy data has been taken using the stock rear tire and gearing.  So in the past, when I provided data related to speed or mileage, it was in “Savage Miles”.  Moving forward, I intend to correct my mileage with the correction factor 1.138.  That may sound wrong, but all my prior data is in Savage miles, so to do any sort of reasonable comparison I need to use the CF.

If you’re lookin for a more relaxed ride, one where your engine isn’t runin it’s guts out and your hands aren’t numb from the high frequency vibes, then this pulley is the hot ticket.  Trimming the spacer instead of the pulley results in about 4mm more spline engagement (a good thing), and it’s easier to machine.

Hope some of you find this report informative.

Best regards,

Mike  

As always, interesting and informative!
So, this begs the question-anyone have one of these spacers I can buy and chop down?
Of course, I still have some of the modified Kawi pulleys….