Just for Fun, V1100 Sport Pistons in PI engine

[John Croucher]

I purchased a set of V1100 high compression pistons many years ago.  I put them in my PI engine.  Did they work? Yes.  I have 210 psi in compression.  With the Magni rear swing arm, front wheel will come off the ground when hitting second gear. 

Was it a direct fit, no.  Had to make the squish band on the pistons wider due to the smaller combustion chamber.  No big deal.  Put them in the lathe and turned down, faced off and blended.
Drilled out the under side to get the weight close to the stock pistons.  Retarded the timing about 3 degrees at idle to get rid of the detonation with regular gas.  There is plenty of room in the combustion chamber due to the smaller valves and lower duration cam. 

Adjusting the timing is easy.  Find TDC, put paint marks on flywheel, 3.75 degree's per tooth for idle advance, turn the TPS very little, about the width of a scribe mark. 

I was going to twin plug a set of heads.  I have sent them off to three people that all said they could twin plug, but always sent them back not done.  I have done the oil journals portion my self and drawn up the dimensions to drill the spark plug holes. 

After assembling with out twin plugs and setting the timing, the engine runs good with out twin plugs.  There is actually very little area of the piston opposite the spark plug that is not exposed to the initial flame front.  And the V1100 Sport is not duel plugged. 

Gonna ride it until it breaks.  Have a fresh new engine sitting on the bench. 

The initial compression reading with just one head on right side and left cylinder bolted on with no head.  The compression dropped when both heads on.  This was probably due to the higher cranking speed.  Then it dropped down with both heads on.  I have not checked the compression since final assembly and a few miles of riding. 

[bigbikerrick]

thats a cool experiment, John. Keep us posted on how it proceeds.   
Rick D.

[AJ Huff]

Cool stuff!

-AJ

[fotoguzzi]

What’s a PI engine?

[Turin]

Same question, was that a Typo for FI/ fuel injected? What sport pistons? Factory pistons or aftermarket? Great stuff!

[John Croucher]

Same question, was that a Typo for FI/ fuel injected? What sport pistons? Factory pistons or aftermarket? Great stuff!

2003 California 1100 Valvole Idrauliche, hydraulic lifter engine.  Fuel injected.   PI is used as an acronym. 

The pistons are stock Sport 1100 or V1100 Sport. 

The heads from the Sports will work on the engine. Creating a big valve low duration cam engine. 

I was reluctant to do the change do to the hydraulic valves.  But my research found that the hydraulic lifters is preferred.

[guzzista]

Nice work, JC, and thanks for sharing it.
PI is short  for  Punterie Idrauliche. Italiano for hydraulic lifters.

[fotoguzzi]

PI is short  for  Punterie Idrauliche. Italiano for hydraulic lifters.

thanks for that.

[jacksonracingcomau]

I purchased a set of V1100 high compression pistons many years ago.  I put them in my PI engine. 

 Retarded the timing about 3 degrees at idle to get rid of the detonation with regular gas.  There is plenty of room in the combustion chamber due to the smaller valves and lower duration cam. 

Adjusting the timing is easy.  Find TDC, put paint marks on flywheel, 3.75 degree's per tooth for idle advance, turn the TPS very little, about the width of a scribe mark. 

Interesting, glad you’re happy with result, but seriously, retarding the ignition timing  by moving the throttle position sensor?
Makes all those “maps” a bit redundant if you can independently  control your ignition timing,

Hope it keeps on making you happy but getting into the map tables might give you more control

[John Croucher]

Interesting, glad you’re happy with result, but seriously, retarding the ignition timing  by moving the throttle position sensor?
Makes all those “maps” a bit redundant if you can independently  control your ignition timing,

Hope it keeps on making you happy but getting into the map tables might give you more control

There will be some more tweaking done.  Scheduling some dyno time to do fueling and mapping.  The bike runs great now.  Timing is set at 7 degrees advance at idle. 

[Turin]

Very cool !  I assume the PI engine uses medium valves and the lawnmower cam ?  Sounds to me like you basically built an improved / 1100 version of an 850 Lemans motor.  It should haul ass!