The potential of the XT/Raptor head is amazing!!!
No Expoxy or welding...

this is a Raptor 778 cc with CUERVO RACING PORTING, 40mm intake valves and 34mm exhaust,,,,set up on a BIG custom LECTRON carb and MSD ignition

if anyone is into drag racing their bike(i doubt that many people but,) there is HUGE potential in this head
we shut the rpm down on it at 10,100.

That is just incredible...

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2008 XTR Mods : DNA Stage 3 Airbox, PC111, Carbon Cans Ovals, Steve Ruth built XTR734cc Big Bore with - High Desert Dyno (HDD)/ Cuervo Racing Gas Flowed / Ported Head fitted with +1mm Valves & uprated Springs, HDD 5050 Camshaft, HDD +3mm Throttle Body, CP 105.5mm 11:1 Piston, Custom Mapping, Piasini ECU, Renthal 613-01, Barkbusters VPS, Pivot Pegz, Touratech Bashplate, Foam Grips, Kev's O2 Sensor Mod, Kev's Extra Coolant Cooler, Wilbers Progressive Fork Springs and Rear Shock

Holy cow that is some big HP & Torque.

I can see it was bored & stroked 778cc, but what cam did you use in that build?

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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

wow looks like i might be looking for a new head...also when did XT660 turn up in USA?

Bloody hell... that's HUGE number !!!!

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RICHARD had sent his head for porting(identical port castings with a slight difference in exterior machine work) but the motor is basically the same

the difference between the 5v head and the 4 valve head is HUGE, u can tell just in the timing changed with the 4 valve requiring 8+* less timing to make peak power, weve done a conversion from a 660raptor(5valve) then installed a 700(4valve) head and cylinder... power potential with ported heads was huge

the camshaft used was one of our customer grinds named HDD5150, its a high rpm camshaft

the efficency of this combo stays true when brought down to a STock bore and stroke 686 cc making a better 8.0 cc per hp vs the 8.2 cc per hp with the 778