Help!! Converting CG200 to 250

Azmon · 05-30-2019, 04:55 PM

My CG200 motor is great, but I feel the need for a little more speed/power and wanted to get a larger piston size for greater displacement.

So I know this has probably been beat to death, but I have searched and don't find any clear cut answers on this.

Can I simply install a 65.5mm or 67mm piston and cylinder, keep my same head- valves, cam etc and be happy as a clam with more power? Or are there other alternatives, like a higher HP liquid cooled motor that would fit the same as my CG200 motor???

Where would the best place to buy parts for this conversion???

Weldangrind · 05-31-2019, 12:07 PM

From my limited experience in this area, the 223/229 (it's not actually 250) has a slightly different frame of architecture than the 200. Swapping the cylinder from a 223/229 wouldn't fit, because the stud spacing is different. Boring the stock cylinder from your stock size (let's guess at 63) to 65.5 or 67 is way too much for that cylinder wall.
You're far better off to just find a bigger motor or massage your 200 to produce more power.

ChipToothy · 05-31-2019, 01:22 PM

As for massaging your 200 there’s a guy with an unmatched 200cc on here. It’s even faster than the 230’s with decking and port work. Maybe he can do a mods list for us.

Wild Dog · 05-31-2019, 02:59 PM

[QUOTE=Azmon;310624
Can I simply install a 65.5mm or 67mm piston and cylinder, keep my same head- valves, cam etc and be happy as a clam with more power? Or are there other alternatives, like a higher HP liquid cooled motor that would fit the same as my CG200 motor???
[/QUOTE]
That's odd because stock CG 200 should come with a 65.5. Unless you got unlucky and got a 63.5.

2LZ · 06-03-2019, 10:35 AM

In my experience between the 200's and 229's I've owned, I felt no real difference in power.

Azhule · 06-03-2019, 12:59 PM

Quote:

Originally Posted by ChipToothy

As for massaging your 200 there’s a guy with an unmatched 200cc on here. It’s even faster than the 230’s with decking and port work. Maybe he can do a mods list for us.

My ears are burning

Lifan 197cc engine... it sees 5,000 to 13,000 feet elevations... every day riding is around 6k feet above sea level... a little asthmatic and down on power up here

Mods list on the "Bashan WILL 200" that goes 80+ mph (gps/follow car verified) is fairly simple... none of my fancy "think outside the box porting" has been done yet...

Emissions delete (Exhaust Air Pump thingy), PCV added, 43mm UNI Pod Filter (Maxima Foam Filter Oil) attached to a "tuned" intake system (did some basic maths to find a length my intake/air filter system needed to be), "Mikuni VM26" (China Carb), exhaust head pipe mountain welds ground down (catalytic is still in there), Honda OE Exhaust/Head Gasket, FMF TurbinCore universal muffler, ATC/ATO Fuse upgrade, Denso Iridium spark plug, Denso 2 wire Coil On Plug, clutch springs upgrade, ceramic wheel bearings, put the bike on a diet (lighter battery, ditched air filter box, etc.), and 17T/39T sprockets*

* Rider is 5 foot 9 inches tall and tips the scales at 120 pounds on a good day... I sometimes drift under 110 pounds thanks to my Crohns... just a tall and skinny toothpick of a rider that has a (slight) addiction to speed

When I finally get the time and some extra cash I will try another top speed run after doing the following: my "Think outside the box porting", upgrade the steering head bearings, aluminum rims, name brand tires, a 35T or smaller rear sprocket (will I reach my 100mph goal?!?), and finally see how it runs on a 28 or a 30mm PWK style carb (PZ30B "Pumper" carb doesn't fit)

05-30-2019, 04:55 PM	#1
Azmon Join Date: Mar 2018 Posts: 28	Help!! Converting CG200 to 250 My CG200 motor is great, but I feel the need for a little more speed/power and wanted to get a larger piston size for greater displacement. So I know this has probably been beat to death, but I have searched and don't find any clear cut answers on this. Can I simply install a 65.5mm or 67mm piston and cylinder, keep my same head- valves, cam etc and be happy as a clam with more power? Or are there other alternatives, like a higher HP liquid cooled motor that would fit the same as my CG200 motor??? Where would the best place to buy parts for this conversion???
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05-31-2019, 12:07 PM	#2
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	From my limited experience in this area, the 223/229 (it's not actually 250) has a slightly different frame of architecture than the 200. Swapping the cylinder from a 223/229 wouldn't fit, because the stud spacing is different. Boring the stock cylinder from your stock size (let's guess at 63) to 65.5 or 67 is way too much for that cylinder wall. You're far better off to just find a bigger motor or massage your 200 to produce more power. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
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05-31-2019, 01:22 PM	#3
ChipToothy Join Date: Apr 2018 Posts: 819	As for massaging your 200 there’s a guy with an unmatched 200cc on here. It’s even faster than the 230’s with decking and port work. Maybe he can do a mods list for us. __________________ Bashan Storm: Ebay steel exhaust wrapped, folding shift lever, seat mod, vm26 carb, air pod, dual led scrambler headlamps, windshield mod, led brake/tail light, secondary led brake light (swingarm), Ebay 295mm rear shock, back up CDI (racing unknown), oil cooler, digital gauge cluster,
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06-03-2019, 10:35 AM	#5
2LZ Join Date: Mar 2010 Location: Volcano, Ca Posts: 7,098	In my experience between the 200's and 229's I've owned, I felt no real difference in power. __________________ "Light a fire for a man, and you heat him for a day. Light a man on fire, and you heat him for the rest of his life." 2007 Suzuki DRZ400S (SM convert) 2009 Q Link XP 200 1967 BSA B25 250cc Starfire 2022 Royal Enfield Interceptor 650 2023 Royal Enfield Scram 411 1948 Royal Enfield Model G 350
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05-31-2019, 02:59 PM	#4
Wild Dog Join Date: Dec 2016 Location: Argentina Posts: 756	[QUOTE=Azmon;310624 Can I simply install a 65.5mm or 67mm piston and cylinder, keep my same head- valves, cam etc and be happy as a clam with more power? Or are there other alternatives, like a higher HP liquid cooled motor that would fit the same as my CG200 motor??? [/QUOTE] That's odd because stock CG 200 should come with a 65.5. Unless you got unlucky and got a 63.5.
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