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Old 13-06-08, 11:49
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Kev Kev is offline
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Join Date: May 2006
Location: Brisbane, Australia
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Quote:
Originally Posted by Freez View Post
I have been doing a lot of research into all kinds of performance parts and if the XT and raptor sleeve length is the same, then it might be possible to increase compression without replacing the piston. Taking the stock XT's 10:1 compression to around 11 and maybe a bit higher. That compression should be fine with a nice high octane fuel you can get from a normal fuel station and should add 1 or 2 HP.

If not, we can still increase compression with playing around with the head, but both options becomes a bit more complicated than just adding a new high compression piston.

Kev, do you know the combustion chamber volume on the stock XT head?
I was going to measure the swept volume when I stripped my motor but did not need to in the end to fit the Raptor piston.

It is easy to machine the cylinder base, to up the compression ratio. Then degree the camshaft to get the cam timing right. One would need a slotted sprocket & once the cam timing is set you would pin the sprocket to the camshaft.
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Mods that I have done to my XTX's

My 04 XTX
Stage 1 & 2 DNA filters / Kev fuel mod / snorkel mod / Drilled air box mod / Engine breather mod / Fork Spacer mod / 15w fork oil /
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My 07 XTX
Raptor 700 cylinder 102mm / Modified Crank Case to take a 105mm Raptor Cylinder / 11:1 102mm JE Raptor piston / Stage 1 Raptor Hot Cam / Ported head / Colder Spark Plug / +2mm Throttle body / DNA stage 1 & 2 filters / Modified Air Box / Snorkel removed / Worry Brothers stage 2 filter cover / 6mm & 8mm Bolts Replaced with Titanium Bolts / Recovered seat in Black / O2 Eliminator /

My 09 XTX
59HP at the rear wheel / Stage 2 Raptor Hot Cam / DNA stage 3 Air Box / Carbon Can Exhausts / Modified Exhaust Link Pipes / PCIII With Custom Fuel Map / Wideband Commander O2 Data logger / LCD100 Dyno Jet display & fuel adjuster / 2500 OHM HT lead instead of a 10K OHM XT lead / Extra Coolant Cooler / Protaper Fat Bars / Tail Tidy With LED Tail Light / OKE Protection Knobs / LED indicators / AIS blocked / Modified rear sprocket rubbers / Rear Foot Pegs removed / 09 ECU With 02 Sensor Changed To A 06 ECU / Complete wiring harnes Changed from 09 to 04 / Home made LED resistor flasher / Hole drilled in the fuel tank filler neck to allow quicker filling / Modified Bar End Weights / Progressive front fork springs, 15W fork oil, forks lowered 25mm, used XTR rear links lowering the rear 20mm, rear spring one click stiffer / Changed front & rear guards from blue to black / 47T rear sprocket / Speedo Healer V4.0 / Kev throttle cam mod / Throttle grip mod / The new 2010 O2 sensor mod is out, works a treat, The new 2012 O2 Controller is out, PM me for details

Now ride a 2018 MT09SP ABS + TCS

My KTM 990 SMR Mod book. http://www.ktmsmt.com/viewtopic.php?f=13&t=4946