Increasing compression on 900 i.e.?

[gatorgrizz27]

Hi, I have been building a Monster with a 2000 900 i.e. motor.  I am keeping the motor fairly tame, running pods, exhaust, power commander, and lightened flywheel. 

I have been considering increasing the compression as well, and looking at different ways to do it.  Obviously pistons are one way, and possibly the best, but what about base gasket reduction and/or decking the head? 

I would love to hear input from those with pumped up motors, I am still wanting to keep reliability and be able to run pump gas, it will be a street bike.

[Duck-Stew]

Drop in 11:1 pistons are the best solution as they retain the squish-band, don't require boring & plating of your barrels and are very coat effective.  There's precious little to be had by adjusting the base-gasket thickness and one should NEVER deck a head as it plays havoc with the combustion chamber & reduces the squish-band (not  good).

[gatorgrizz27]

Thanks!  I've been playing with my 2-stroke KTM for too long I guess.    Obviously valve clearances would have to be accounted for with anything besides pistons.  I am assuming the pistons would increase the snap off of the bottom, how would they affect the top end or spin up of the motor?

[Speeddog]

A little info:

http://www.bikeboy.org/900carbhighcomp.html

http://www.bikeboy.org/900sscarb944.html

http://www.bikeboy.org/900ssiehicomppistons.html

[Drunken Monkey]

Yep, Bikeboy is the best site for real world information on 'what mods do what' on the older engines.

The only mod he doesn't have info on is the MBP kits, and these will supposedly get you up to the 100+ HP range.

http://www.ca-cycleworks.com/shop/heads/heads.html

(Mind you, you end up paying about $200 per extra HP, as the whole shebang is around $3K  )

[koko64]

At least on an 900ie you won't have to retard the ignition at the pick ups due to a more progressive and refined ignition map than the carb models.

[greenmonster]

I`ve ditched cylinder gasket on both my 2V 900`s, HC in both. About 0.4-0.5 more comp w that.
Got squish just above & under 1.00 mm, which is close to ideal & safe.
Works fine but I also have programmable ignition & ECU on them.

Otherwise, +1 on duckstew, you`ll be happy w that.

[gatorgrizz27]

Spent quite a few hours reading the bikeboy pages, awesome resource!  I had it bookmarked awhile back but lost everything.  Now its tempting me to build up the motor quite a bit more without going full out crazy with heads and all. 

Any input on timing with the i.e. motor?  Can it adjust on its own to prevent detonation if needed or is it tweakable with the power commander?  Some pages mention reflashing the stock ECM as well, but I won't have dyno/tuner abilities for that.  Engine tuning is a whole nother realm in and of itself to play with!

Also if anyone cares to keep performance discussions going, I need to build a full exhaust for the bike as it will have undertail exhaust.  I could use the stock headers and cut it and splice on, but was planning to build a whole system for a cleaner look.  Any input on primary diameter out of the ports?  I was planning to run 1.75" tube, but some things suggest matching the port diameter to the primary diameter perfectly to keep velocity up.  Also considering crossover or bypass location, pipe length, and so on.

[Speeddog]

'00 IE ignition will not adjust on it's own, and AFAIK no PowerCommander for a Ducati adjusts timing.

[greenmonster]

And no issues w freeplay JE 11:1 pistons to heads either, measured +2mm.

[junior varsity]

fun thread, but not sure why it is a sticky

[Drunken Monkey]

fun thread, but not sure why it is a sticky

Me neither. Unstickying it.