Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 999 / 749 > high compression pistons for 999R/998R?

[nelly]

Both the Pistal and the JE are good pistons. The thing to watch is the weight difference vs. your stock ones. You may need to rebalance the crank/rods etc. and that means a strip down.

[wilf]

As nelly says... i don't think that JE or Pistal do a 'drop in piston'

I think pistal list one but it is too far out on weight.

You have to be carefull as some manufactures list pisons as 'Drop in' but they mean it has the same deck height so you shouldn't have a problem with squish clearance - this is for engine builders that dont re-measure and reset the squish (not a good idea).

There is not a great deal of gain by fitting Hi comp pistons on the 'stretta motors, If you get the compression ratio/squish measured you may be surprised how far out they are from perfect. They are built with very safe clearances and can often be optimised to get a fair bit more compression with the pistons you have. (and you get a better flame path and more efficient combustion chamber with flatter topped pistons.)

Best tuning options.. minimise squish, minimise valve clearances, dial in cams, large exhaust system (54-57 ideal), pcIII and custom map.

Wanna get carried away... fit light flywheel, port heads & match inlets & Exh. ports.

Steve's just done a 999R Xerox - 57mm termi, PCIII, cam's dialled in (were a long way out too!) with only 600 miles on it made 155 RWBHP on our dyno, made 132 'out of the box'

MEGA!

[chillo]

ok, to take this further what actually is involved to 'balance' the crank?
Got a pc3 already, looking at a 57mm exhaust options, cams to be dialed in and possible lap valves etc
i'm not really worried about top line bhp figures, more interested in a smooth motor that is put together with more skill/care than out of the factory etc.
Its not an issue with regards to splitting the motor.
How far out weight wise is the pistal piston? are the standard pistons cast or forged?

[andyb]

I still dont understand why? What are your gains versus the costs of all that work, if you dont want/ need horses?

I have 57mm pc111 and just had my cams and valve clearances optimised at jhp. The engine undoubtedly runs smoother, and has probably gained a bit more power. This versus the cost is IMHO worth it, and a justifiable bit to do.

Where do you want to stop? To balance the crank you will need a complete strip down...
I understand just the 2 gaskets that go under the cylinders are around £100.................

[uncledunnie]

[quote=chillo]
.....i'm not really worried about top line bhp figures, more interested in a smooth motor that is put together with more skill/care than out of the factory etc.
QUOTE]

Speak to Neil Spalding (Sigma), he did exactly that to my 999s 2 years ago.

The work was based upon his "Full Monty" package and while the motor was out he ported the head to suit the 57mm termi's already fitted, then added the PC3 and custom mapped it. It currently runs factory cam timing and is in what he would describe as a road tune, i.e completely usable.

If you're due a major service - look at the ££'s, the "Monty" doesn't cost a lot more.

I now have a well put together motor that runs very very sweet and pulls like a train.

Worth it in my opinion.

[chillo]

Originally Posted by uncledunnie

I now have a well put together motor that runs very very sweet and pulls like a train.

Worth it in my opinion.

exactly!

[Ray]

I had a set of Pistals fitted to my 998r. Was led to believe they were a straight swap, just a piston swap ain't gonna gain anything but they are cheaper than OEM?

For some bizarre reason the cam timing on a lot of 999r type engines is out as it leaves the factory.

Bang for buck wise get the cams dialled in and a powercommander, then a dyno session to set it up.

You can tune the cam timing for mid range or top end. My bike, a 998r was about 4 degrees out, now its set to spec and the mid range a whole lot better. Also had the squish set and in my case the preload on the main bearings? was too tight. Only gained a few BHP at the top but about 5 mid range. The fueling is still a bit on the weak side so a power commnader is needed to sort that out.

If you just wanna liven the thing up just change the rear sprocket! Having said that change the gearing might just mean the front wheel spends even more time in the air!

Ray.