Big bore kit for 223cc/zs165mm

stoppre12211 · 11-11-2024, 03:49 PM

hey guys.

Not sure if this is a bad solution, but I was really hoping to bore out my 223cc/zs165mm on my Vitacci Titan EFI. The only bore kit that fits the 15mm wrist pin available will go from a 65mm piston to a 67mm piston. I dont find that gain worth the effort. But I was wondering, could I use 15mmIDx16mm or 17mm to fit the larger wrist pin requirements of other cg250 big bore kit. Just raise the wrist pin OD to fit the 17mm 72mm-75mm bore kits. Let me know what you think.

I know its going to have ramifications to compression ratio and EFI flash but would this wrist pin sleeve solution even be viable. thanks.

existing max big bore kit https://gstreetperformance.com/cdn/s...8155&width=990

bore kit that would require sleeve to raise from 15mm wrist pin to 16mm wrist pin.
https://www.aliexpress.us/item/32568...yAdapt=glo2usa

dirtbkr188 · 11-11-2024, 04:56 PM

You intend to use the stock 15mm wrist pin from your engine and insert sleeves to use a piston that takes a bigger diameter wrist pin? Not sure I'd want anything to do with that, but that's just my 2¢...

SpadeJerricho · 01-15-2025, 06:21 PM

check alixpress ive found a 70mm bigbore kit for the engine and it was a 15mm wrist pin size

XLsior · 01-15-2025, 07:12 PM

70mm bigbore cylinder kits wont fit any GC engine below a 167FMM.

it wont fit, the head studs are positioned different and the cylinder skirt OD 73mm wont fit into the case.

Gudgeon/wrist pin sizes are the lest of problems...

If you want more power save up and get a pr172-fmm PR175-fmn-5 300cc* (5 or 6 speed with or without a balance shaft) or a 4 valve CB300RL some fabrication required.

Or just got to wall mart and get a CG250 for less than $500USD.

I've done the CG250 70mm bigbore kit, I would only consider doing it if you old cylinder and piston is worn out as the power increase is negligible.

11-11-2024, 03:49 PM	#1
stoppre12211 Join Date: Nov 2024 Posts: 4	Big bore kit for 223cc/zs165mm hey guys. Not sure if this is a bad solution, but I was really hoping to bore out my 223cc/zs165mm on my Vitacci Titan EFI. The only bore kit that fits the 15mm wrist pin available will go from a 65mm piston to a 67mm piston. I dont find that gain worth the effort. But I was wondering, could I use 15mmIDx16mm or 17mm to fit the larger wrist pin requirements of other cg250 big bore kit. Just raise the wrist pin OD to fit the 17mm 72mm-75mm bore kits. Let me know what you think. I know its going to have ramifications to compression ratio and EFI flash but would this wrist pin sleeve solution even be viable. thanks. existing max big bore kit https://gstreetperformance.com/cdn/s...8155&width=990 bore kit that would require sleeve to raise from 15mm wrist pin to 16mm wrist pin. https://www.aliexpress.us/item/32568...yAdapt=glo2usa
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11-11-2024, 04:56 PM	#2
dirtbkr188 Join Date: Aug 2009 Posts: 579	You intend to use the stock 15mm wrist pin from your engine and insert sleeves to use a piston that takes a bigger diameter wrist pin? Not sure I'd want anything to do with that, but that's just my 2¢...
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01-15-2025, 06:21 PM	#3
SpadeJerricho Join Date: Dec 2024 Location: AZ Posts: 2	check alixpress ive found a 70mm bigbore kit for the engine and it was a 15mm wrist pin size
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01-15-2025, 07:12 PM	#4
XLsior Join Date: Aug 2020 Location: Australia Posts: 1,523	70mm bigbore cylinder kits wont fit any GC engine below a 167FMM. it wont fit, the head studs are positioned different and the cylinder skirt OD 73mm wont fit into the case. Gudgeon/wrist pin sizes are the lest of problems... If you want more power save up and get a pr172-fmm PR175-fmn-5 300cc* (5 or 6 speed with or without a balance shaft) or a 4 valve CB300RL some fabrication required. Or just got to wall mart and get a CG250 for less than $500USD. I've done the CG250 70mm bigbore kit, I would only consider doing it if you old cylinder and piston is worn out as the power increase is negligible.
	0