- Location
- NYC/Long Island
See my build thread for pictures: http://www.x-h2o.com/index.php?threads/carbon-rok-rebuild.147550/
I bought a carbon ROK last Summer that had a stock SXR driveline in it with only a head and pipe as bolt ons. Over the Winter I ported it with the Sport Port templates and bored the cylinder to 82.50mm.
The sport port cost $70 and it comes with 2 magnets.
The first magnet is for the exhaust port. I stuck it to the cylinder wall and with some bright green spray paint, I painted it to make up my template. Remove the magnet and go to town with the grinder. The magnet is supposed to be set to the very top of the cylinder, and it actually raises the exhaust port height. This would make more power at the expense of response. After speaking to the owner of sport port, he said I could keep the stock exhaust port height and just widen it with the template. So I lowered the template a few millimeters and just widened the exhaust port. I used a dremel with the pencil attachment, an assortment of mini sanding drums and carbide burrs to do the job.
I believe widening the exhaust port creates power all over, the only reason OEM doesn't do it, is because it reduces piston ring life. Remember these engines need to make it past warranty period. I think this is relatively free power. The SXR cylinders are pretty good as they are, the transfer and boost ports match great with the sleeve. This is because Kawasaki casts the cylinder around the sleeve as opposed to Yamaha; who presses the sleeve in after casting the cylinder.
The second magnet goes to the bottom of the piston, where you're supposed to cut a window on the skirt of the piston. If you look at the Kawasaki SXR sleeves, they come factory with a "window" to the boost port. When the piston is close to bottom, air/fuel travels underneath the piston, through the window and into the boost port. Kawasaki however never included pistons that worked with this window in the sleeve. I guess they figured let aftermarket take care of it. And aftermarket did; Wiseco offers pistons with this window cut out already. I wasn't aware of that until after I bought Pro-X pistons.
While I had the motor apart, I also ported the cases. Unfortunately there's no template to help decide how much to grind here. I just kept installing the cylinders, look through the intake and see where and how much I should remove to get around around the sleeve and help feed the transfers. Fortunately, it's not that difficult to do compared to Yamaha. SXR cases don't need epoxy work.
Water test everything went good. Definately an increase in response and power. Suprisingly, the carbon ROK moves great considering the minimal expense and limited driveline mods done. I stepped up a impeller pitch compared to factory SXR pitch. The engine definately could've pushed a steeper pitch especially inside the light hull. I did step up a pilot jet and main jet.
Pilot 82.5
Main 155
Low Speed Adjuster 3/4 Turn
High Speed Adjuster 2 1/4 (definately on the rich side)
Sport Port Cylinder 82.5mm Bore
Ported Cases
Blowsion Flame Arrestors
Skat-Trak Impeller (Pitch 1 Size larger than stock SXR)
81mm Nozzle
ADA Head 32cc Domes (93 Octane)
Factory B Wet Pipe
I bought a carbon ROK last Summer that had a stock SXR driveline in it with only a head and pipe as bolt ons. Over the Winter I ported it with the Sport Port templates and bored the cylinder to 82.50mm.
The sport port cost $70 and it comes with 2 magnets.
The first magnet is for the exhaust port. I stuck it to the cylinder wall and with some bright green spray paint, I painted it to make up my template. Remove the magnet and go to town with the grinder. The magnet is supposed to be set to the very top of the cylinder, and it actually raises the exhaust port height. This would make more power at the expense of response. After speaking to the owner of sport port, he said I could keep the stock exhaust port height and just widen it with the template. So I lowered the template a few millimeters and just widened the exhaust port. I used a dremel with the pencil attachment, an assortment of mini sanding drums and carbide burrs to do the job.
I believe widening the exhaust port creates power all over, the only reason OEM doesn't do it, is because it reduces piston ring life. Remember these engines need to make it past warranty period. I think this is relatively free power. The SXR cylinders are pretty good as they are, the transfer and boost ports match great with the sleeve. This is because Kawasaki casts the cylinder around the sleeve as opposed to Yamaha; who presses the sleeve in after casting the cylinder.
The second magnet goes to the bottom of the piston, where you're supposed to cut a window on the skirt of the piston. If you look at the Kawasaki SXR sleeves, they come factory with a "window" to the boost port. When the piston is close to bottom, air/fuel travels underneath the piston, through the window and into the boost port. Kawasaki however never included pistons that worked with this window in the sleeve. I guess they figured let aftermarket take care of it. And aftermarket did; Wiseco offers pistons with this window cut out already. I wasn't aware of that until after I bought Pro-X pistons.
While I had the motor apart, I also ported the cases. Unfortunately there's no template to help decide how much to grind here. I just kept installing the cylinders, look through the intake and see where and how much I should remove to get around around the sleeve and help feed the transfers. Fortunately, it's not that difficult to do compared to Yamaha. SXR cases don't need epoxy work.
Water test everything went good. Definately an increase in response and power. Suprisingly, the carbon ROK moves great considering the minimal expense and limited driveline mods done. I stepped up a impeller pitch compared to factory SXR pitch. The engine definately could've pushed a steeper pitch especially inside the light hull. I did step up a pilot jet and main jet.
Pilot 82.5
Main 155
Low Speed Adjuster 3/4 Turn
High Speed Adjuster 2 1/4 (definately on the rich side)
Sport Port Cylinder 82.5mm Bore
Ported Cases
Blowsion Flame Arrestors
Skat-Trak Impeller (Pitch 1 Size larger than stock SXR)
81mm Nozzle
ADA Head 32cc Domes (93 Octane)
Factory B Wet Pipe
