I installed a 95mm Wiseco in my Cafe' bike the winter of 2013.  At that time the only choices you had were DR650 pistons in 95mm, 96mm or 97mm.  I chose the 95mm as I really didn't know what to expect for reliability/durability - and I wanted the ability to bore again if things went bad.

I have been running the 95mm for the last 14,000 miles and it works great, doesn't burn any oil, runs smooth, and it provided a noticeable power increase (along with a performance cam, head porting).  For the first year I ran the stock carb, air cleaner and the exhaust system was a Dyna muffler.

For all of that time I was running premium fuel, as we all believed the compression ration was 10.5:1 - which is what Wiseco listed for the piston when used in the DR650.  DragBikeMike has done all the math and determined the pop up DR650 piston when installed in the Savage engine has a 9.2:1 compression ratio for the 94mm piston and 9.5:1 for the 97mm.....that would place my 95mm at 10.3:1 compression.

So I looked up a couple of Suzuki single cylinder bikes for comparison.  The TU250 has a compression ratio of 9.2:1 and the DR650 has a compression ration of 9:5:1 - and both are approved for using "regular" grade fuel.

So.....yesterday I went on a ride and stopped at the gas station and put 2.5 gallons of 87 octane in my Cafe' bike (a bit more than 1/2 gallon of premium was in the fuel tank at the time).........and I went for a 60 mile ride in 75 degree weather.  I was riding my standard country roads which keep the engine between 3,000 - 3,500 rpm and I seldom used more than 1/2 throttle to maintain the 50mph speed that suits the curvy roads.  I could not tell any difference in the way the bike ran and I sensed to objection from the engine for the lower octane fuel.  I did a couple of full throttle acceleration runs in 4th gear up to 4,000....and the engine sounded just fine with no hint of knocking or pinging.

So.....maybe regular fuel works fine in the Savage engine with the DR650 pistons.  I am going to give it a try until I hear the engine file a complaint!

Has anybody else running a Wiseco tried regular fuel?

I felt mine pinging with regular but I can run the mid grade when available, premium otherwise.

Versy:

I didn't hear any pinging on my easy ride.....but I did have a bit of Premium left in the tank and that may have bumped up the octane sufficiently.

And......perhaps the fuel they brew in California is a bit different than what they have in KY.  I will try again with the next fill up and see if a second tank will still run fine in my engine. In rural areas where most cars and trucks use Regular fuel - the Premium can sit in the tanks for a very long time and can be old when you buy it.

It is not that I can't afford Premium - but it is nice to know that regular can be used in a pinch........as we learned in Arkansas some rural gas stations only carry Regular and Diesel.

justin_o_guy2 wrote on 10/07/21 at 14:21:26:


I am not into octane boosters.....they are expensive and it takes a lot of it to make a difference.  It costs about $0.25 a gallon to raise the octane up 3 numbers (using Royal Purple).

But.....I can see that storing a small bottle on a bike that requires Premium might help you get through a place like Arkansas.  My F800GT requires 89 octane and some stations only had 87.....a small bottle of Octane Booster could be added to bump the octane up 2 or 3 numbers - however that little amount of Octane booster will likely be worth $2.