Turn your timid little KLX250S into a Fire Breathing 330cc Monster! :mrgreen:
That's 80cc more displacement, 5-6 more horsepower and ~30% MORE TORQUE!
Kustom Kraft 330cc Big Bore Kit for Kawasaki KLX and D-Tracker- a DIY installation guide.
Note to the Pudgy Picture Thief: All text and images © Marc Nisam. All Rights Reserved.
Begin by removing the fuel tank and cylinder head cover bolts, then remove the cylinder head cover.
Drain the coolant remove the radiator hose and remove the thermostat-
Remove the throttle body assembly and the exhaust header. Remove the upper engine mounting bracket:
Remove the oil pipe banjo bolt:
Remove the camshafts and the front camshaft chain guide, then remove the cylinder head bolts, beginning with the smaller M6 bolts:
Once the two M6 bolts have been removed, remove the larger M10 bolts:
Remove the cylinder head:
Be careful not to lose either of the dowel pins!
Cylinder head-
Valves and spark plug-
Remove the lower radiator hose:
Remove the cylinder-
To remove the piston first remove the piston snap rings:
Then remove the piston pin:
Note- this step normally calls for a special tool: "Piston Pin Puller Assembly" but it's not hard to make one using one of the cylinder head M6 bolts, some spacers and washers and the new piston pin to push out the old pin:
Push out the piston pin far enough that you can remove the piston:
No replacement for displacement! 330cc vs 250cc!
Lord of the Rings
Install the new rings:
First install the oil ring expander (the wavy ring) and make sure the ends touch but don't overlap. The install the oil ring steel rails, one above the expander ring and one below. There is not "top" or "bottom" for these rings.
Next install top and second rings. Top ring is white/silver while second ring is blackish. Install these rings with the marks facing up.
Grease the inside of the con rod:
Install the new piston with the arrow pointing forward:
Install the new piston pin and new snap rings:
With the new piston installed make sure the ring openings are aligned as shown:
Apply liquid gasket to the upper surface of the crankcase, install the two dowel pins and install new cylinder base gasket and new cylinder:
I don't have a piston ring compressor tool but find it's not hard to compress these rings by hand. Oiling the piston rings and cylinder wall makes reassembly a lot easier.
New cylinder installed:
Install dowel pins, new cylinder head gasket and front camshaft chain guide:
TBC :mrgreen:
That's 80cc more displacement, 5-6 more horsepower and ~30% MORE TORQUE!
Kustom Kraft 330cc Big Bore Kit for Kawasaki KLX and D-Tracker- a DIY installation guide.
Note to the Pudgy Picture Thief: All text and images © Marc Nisam. All Rights Reserved.
Begin by removing the fuel tank and cylinder head cover bolts, then remove the cylinder head cover.
Drain the coolant remove the radiator hose and remove the thermostat-
Remove the throttle body assembly and the exhaust header. Remove the upper engine mounting bracket:
Remove the oil pipe banjo bolt:
Remove the camshafts and the front camshaft chain guide, then remove the cylinder head bolts, beginning with the smaller M6 bolts:
Once the two M6 bolts have been removed, remove the larger M10 bolts:
Remove the cylinder head:
Be careful not to lose either of the dowel pins!
Cylinder head-
Valves and spark plug-
Remove the lower radiator hose:
Remove the cylinder-
To remove the piston first remove the piston snap rings:
Then remove the piston pin:
Note- this step normally calls for a special tool: "Piston Pin Puller Assembly" but it's not hard to make one using one of the cylinder head M6 bolts, some spacers and washers and the new piston pin to push out the old pin:
Push out the piston pin far enough that you can remove the piston:
No replacement for displacement! 330cc vs 250cc!
Lord of the Rings
Install the new rings:
First install the oil ring expander (the wavy ring) and make sure the ends touch but don't overlap. The install the oil ring steel rails, one above the expander ring and one below. There is not "top" or "bottom" for these rings.
Next install top and second rings. Top ring is white/silver while second ring is blackish. Install these rings with the marks facing up.
Grease the inside of the con rod:
Install the new piston with the arrow pointing forward:
Install the new piston pin and new snap rings:
With the new piston installed make sure the ring openings are aligned as shown:
Apply liquid gasket to the upper surface of the crankcase, install the two dowel pins and install new cylinder base gasket and new cylinder:
I don't have a piston ring compressor tool but find it's not hard to compress these rings by hand. Oiling the piston rings and cylinder wall makes reassembly a lot easier.
New cylinder installed:
Install dowel pins, new cylinder head gasket and front camshaft chain guide:
TBC :mrgreen: