[quote author=363C3A323E316B6E666C5F0 link=1554362214/30#44 date=1557538261]DragBikeMike wrote on 05/06/19 at 23:30:36:


When I built my engine I chose the 95mm, as it was the smallest Wiseco piston available at the time (Lancer had not had the custom Wiseco in the stock 94mm size being built yet).

The reason I used the smallest piston - is that I seldom need to use "all" the HP that my engine can make, and the majority of my riding is done on twisty county roads between 40-60 mph....and this requires 1/4 - 1/2 throttle.  I wanted an engine that was economical, reliable and ran well - I was not after maximum HP.  I also wanted to be able to bore the cylinder again if needed - however I now realize that the Savage engine really doesn't have any piston/cylinder issues as long as you keep the oil level up and use a good oil - Youzguyz got 160,000 miles on his bike and was able to re-use the piston and cylinder when he had his engine overhauled.

I think the cylinder head is the big restriction in how much power the engine can produce - and on a dyno the piston size is likely to make a difference on "where" the power is produce - more than on how much power is produced.  I believe there is a possibility the larger pistons will reach the airflow limits of the head at a lower rpm than the smaller pistons will.  So....I would expect the 94mm piston will have the maximum torque at a bit higher rpm than the 97mm piston will.  The bigger pistons will make a bit more torque than the smaller pistons....but they will likely start to run out of air a bit sooner than the smaller pistons will.

So - I believe that if you want maximum bottom end grunt, you should go with the bigger piston.....even as big as the 97mm.  If you want a good running engine that makes more HP because of the higher compression ratio.......but do not use full throttle often.....go with a 94mm piston and save the cost of the cylinder boring if your cylinder is in good shape.

I am well satisfied with how my 95mm Wiseco engine runs.....it is a joy to ride.  Maybe someday I will build a 97mm engine and see if I am missing anything.

So

philthymike, You say you say better mileage with the big kit, with the h/c piston do you run hitest? Is the better mileage enough to make up for the increase in cost for hitest?

badwolf wrote on 05/11/19 at 10:23:39:


Yeah I’ve got to run super now but the engine runs more efficiently with higher CR and takes alot less throttle than before. Up on the interstate I used to have to keep the throttle nearly pegged to keep up with 70 mph traffic. Now it’s quite alot less throttle for the same speed. To be perfectly honest I haven’t pegged the throttle at all since the upgrade. Once I get the bike up to 85 the light weight starts freaking me out on the rutted washboard mess PA calls a highway. But I’ve hit 90 and still had a bit of throttle left.

I don’t sweat about the cost of super with such a small tank. My Ducati averages 49 mpg according to its calculator and i go much much farther on a tank of gas in the Thumper than I can on the Ducati. If I was to guess I’d say I’m in the neighborhood of 56+ mpg. That’s riding heavy handed too.

My most recent check yielded milage in the low 60’s.
Good efficient performance and milage can co-exist and be fun at the same time.  
Besides, REX SOUNDS GREAT when HE is howling !

60's?!  

Crap, I struggle to get 50's out of my cleanly jetted mostly stock bike with my fat ass (6'3" 250 lbs)  on it.  :'(

Iceman4193 wrote on 05/22/19 at 17:26:24:

I don't know if Comp Cams does Savage Cams.

Web Cam does - but their cam grinds for the Savage aren't much better than stock.  The Stage 3 that Lancer sells is his own design, and Web Cam does not offer that grind to the retail market.

The stock DR650 cam has the oil system set up a bit different.  The center hole is smaller, and there are no holes at the base of the ramp in the cam like the Savage has.  DragBikeMike has been using the DR650 cam successfully without the holes - however we have also found that the holes can be drilled.