Getting more out of the S2R800 Engine

[TitanMonsterS4R]

The title says it all.  How can one get more out of an S2R800 engine.  The bike currently has pod filters, a quat-D exhaust and a Techlusion EFI.  Not looking to get 100hp out of her but I've heard things like HP pistons or a big bore kit will increase HP.  What the best way to get as much out of this durable little engine and what's the potential increase in HP I receive with the upgrade.  I could easily go out and buy anS2R or S4 engine and drop her in there, but where would the fun in that be and as much as I like the coffee can rattle sound of a dry clutch, I love the wet clutch.

Thanks for the advice DMFers

[bikepilot]

I'd research the pods a bit, the more airbox volume the better for twins as a general rule of thumb, though the monster's airbox isn't great -- maybe its bad enough that pods are actually better, I dunno.

Generally more compression and displacement is a good bang-for-buck method of getting more power.  CA cycleworks lists 91mm pistons for the monster 800.  http://www.ca-cycleworks.com/shop/catalog/ducati/engine.html  That'd give 859cc and, I'd guess, more compression.  With its comparatively short stroke I would think you could get by with quite a bit more compression than is typical of the big case motors.

[teddy037.3]

higher comp pistons would be the way to go. I had... 88mm (I think... it's been a while) FBF pistons that bumped comp to 11:1. they also made a 12:1 set (these are made for the 750/800 motor. I had a 620 and swapped cyls, too).
lighter weight flywheel is another thing you can add.  otherwise, port and polish for the heads and a dyno-tune for your bike will get you pretty close to maxed out. not sure what cams are swappable into the small case heads.

also (not HP, but performance related) I hear lighter wheels are great

[TitanMonsterS4R]

I'd research the pods a bit, the more airbox volume the better for twins as a general rule of thumb, though the monster's airbox isn't great -- maybe its bad enough that pods are actually better, I dunno.

Generally more compression and displacement is a good bang-for-buck method of getting more power.  CA cycleworks lists 91mm pistons for the monster 800.  http://www.ca-cycleworks.com/shop/catalog/ducati/engine.html  That'd give 859cc and, I'd guess, more compression.  With its comparatively short stroke I would think you could get by with quite a bit more compression than is typical of the big case motors.

I wasn't thrilled with pods when I bought it but I figured with the last setup I had we put holes in the airbox to open it up a bit and let the bike breathe.  Thanks for the Ca-Cycleworks link.  Will definitely look into going to 859cc. 

[bikepilot]

I agree re the light weight wheels, they can make a huge difference in turning, acceleration and braking. 

Re the pistons for the 750, the bore and valve pockets should be the same I think.  I dunno if the pin or crown height are the same -- the 750 and 620 have a shorter stroke crank so plausibly could have different piston specs.  Worth checking before you buy if you go that route.

[teddy037.3]

Re the pistons for the 750, the bore and valve pockets should be the same I think.  I dunno if the pin or crown height are the same -- the 750 and 620 have a shorter stroke crank so plausibly could have different piston specs.  Worth checking before you buy if you go that route.

620 bore is smaller than 750, same stroke. 800 is the same bore as 750, longer stroke. when I did the 620 I just bought 750 barrels and the FBF pistons, they bolt right on and kept the 620 heads.  when I still had my monster I was debating on changing the flywheel and crank to basically make it a hi-comp 800.

:edit: the top end of the 750/800 are identical; piston kits made for 750 fit 800

[Raux]

PM StopinTime

[Travman]

Kopfjager has a M800 with a lot work done to it including a 859 bore and dry clutch conversion. Maybe he will chime in here soon. I believe his motor work was done at DucShop in Atlanta.

[Raux]

Kopfjager has a M800 with a lot work done to it including a 859 bore and dry clutch conversion. Maybe he will chime in here soon. I believe his motor work was done at DucShop in Atlanta.

thought his was a 750

[booger]

I could easily go out and buy an S2R or S4 engine and drop her in there, but where would the fun in that be

The fun would be found in your wallet. Getting that engine to produce any more real power would cost a mint and may make it less reliable. Lose the pods and Techlusion gimmick. Cut the airbox and put it back in there with a K&N, then flash the ECU to DP spec. Nothing works as well as a DP chip.

After that perhaps lighten your stock flywheel and get the heads lightly ported but not polished. Then get some lightweight wheels and declare victory. If you look at increasing your power to weight ratio as an exercise in both mild engine work and lightening the chassis, you may not have to go so far either way to satisfy yourself.

Spending a shit-ton on an 800cc wet clutch engine is not the way I would play it. I like the engine and know firsthand how hardy it is but you won't get your money's worth from doing heavy engine mods on it.

[Raux]

It's possible to get nearly 100hp at the crank on the 800.

[suzyj]

Is it possible to put 796 (696?) heads on?  I'd imagine they'd flow a lot better than the stock 800/695 heads.

[Speeddog]

696/796 heads are better design, like the DS1000 heads, but...

They use a head gasket, so you'd have to use the cylinders too.
Unfortunately, the base gasket is a different part#, so 696/796 cylinders may not fit the 695/800 crankcases.

[TitanMonsterS4R]

Spoke with Chris at Ca-Cycles and turns out that the 859 pistons are no longer being produced and purchasing would cost around $3K. WTF.  Thanks for all the insight, keep it coming.  Most suggestions have been to locate a S2R1K engine and drop it in the bike.  Not that I'm looking to waste cash just curious as to how I can make this S2R unlike any other out there, understanding that the more unique it is the more I might be asking for trouble.

At one point I investigated converting the engine to a dry clutch.  Cost was roughly $3K.

[bikepilot]

Bummer.  $3k is way too much though, JE and CP will do custom pistons for much, much less.  I think more like $300/ea.  JE I think has a minimum order of 4, CP might do just two.  A drop-in piston with more compression might be a good move though, especially if the 750 pistons work -- put those in, tidy up the ports, set the squish etc., and I bet you'd have significant gains.