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sqwert · 05-28-2018, 10:46 PM

Got back in town last night late, picked up the 300cc kit and took a look at it this morning. Nicely packaged to prevent shipping damage. All 8 corners of the shipping box were crushed, but not a mark on the inner box with the padding to keep the parts secure. Nice work!

I don't even know what all the extra pieces are for. The head and base gaskets come with the kit, but NZ included what looks like a complete top end gasket and seal set. I feel so spoiled. I'm due a bit of vacation on 31 May so about then I'll start the install.

I expect the bore kit with maybe a couple teeth on a new rear wheel sprocket will eliminate any craving for a 450. 250cc is fast enough for me and then some, just want more torque when loaded for a trip. 300cc should do that.

Thinking about buying another RX3 and doing some measurement on a complete teardown to see if there is room for a stroker crank. Need to get a few 300s thumping around to test durability of the rest of the driveline before spending a ton on stroker development. The 250 high rpm powerband feels like the head, cam EFI, and exhaust can provide good performance for a 350cc ADV bike stock. Won't rev like a crotch rocket, but the powerband will probably begin at idle and go steady up to 8500 to 8700rpm.

Then, there's always porting, polishing, port matching, maybe bigger valves will fit, less restrictive air filtration, and a custom exhaust. I have a potential source for cams, too. Those mods will compromise a bit of the bottom end, but if properly tuned and the ancillaries will hold up, I expect knocking on 40hp and still comfortably streetable.

Been a while since I tweeked a new engine. Always a fun project.

05-28-2018, 10:46 PM	#17
sqwert Join Date: Jun 2017 Posts: 382	Got back in town last night late, picked up the 300cc kit and took a look at it this morning. Nicely packaged to prevent shipping damage. All 8 corners of the shipping box were crushed, but not a mark on the inner box with the padding to keep the parts secure. Nice work! I don't even know what all the extra pieces are for. The head and base gaskets come with the kit, but NZ included what looks like a complete top end gasket and seal set. I feel so spoiled. I'm due a bit of vacation on 31 May so about then I'll start the install. I expect the bore kit with maybe a couple teeth on a new rear wheel sprocket will eliminate any craving for a 450. 250cc is fast enough for me and then some, just want more torque when loaded for a trip. 300cc should do that. Thinking about buying another RX3 and doing some measurement on a complete teardown to see if there is room for a stroker crank. Need to get a few 300s thumping around to test durability of the rest of the driveline before spending a ton on stroker development. The 250 high rpm powerband feels like the head, cam EFI, and exhaust can provide good performance for a 350cc ADV bike stock. Won't rev like a crotch rocket, but the powerband will probably begin at idle and go steady up to 8500 to 8700rpm. Then, there's always porting, polishing, port matching, maybe bigger valves will fit, less restrictive air filtration, and a custom exhaust. I have a potential source for cams, too. Those mods will compromise a bit of the bottom end, but if properly tuned and the ancillaries will hold up, I expect knocking on 40hp and still comfortably streetable. Been a while since I tweeked a new engine. Always a fun project.
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