look what I found 250cc big bore kit for $85

[stretch8668]

http://www.aliexpress.com/item/65-5mm-Big-bore-Kit-Change-air-200CC-to-250CC-Zongshen-Shineray-Bashan-Dirt-Pit-bike/752119365.html says it'll turn a 200cc into a 250cc has anyone done it plus its $85 shipped

[FastDoc]

Free shipping too.

Web site looks a little dubious though. The pop ups were in Russian.

[Weldangrind]

It won't actually be 250; more like 223.

That assumes that your existing piston is less than 65.5mm. I have an OHC motor that was labeled as 200cc, and it has a whopping 68.5mm bore and a tiny 52.5mm stroke. My plan is to use the existing bore with a 66.2mm stroke to make 244cc. That is unprecedented in an air cooled OHC China motor, AFAIK.

If you'd like me to share the math, just LMK.

[Weldangrind]

I just did a little math based on your 163FML engine stamp, and it seems that you have a 64mm stroke. If that's true, your engine would go from 200cc to 216cc by swapping to a 65.5mm piston.

That said, the engine stamp is not necessarily correct. My OHC motor stamp translates to 125cc, but it's actually 200cc. The only way to know for sure is to remove the head and measure the bore and stroke.

[stretch8668]

Be good for when ever needed rebuild cause I don't see the sence for $85 for 16cc and I also noticed the pop up I found another site in cananda for the same kit just didn't have price with it

[stretch8668]

Here's other link for one in Canada http://www.chinese-parts-canada.com/4_stroke_big_bore_kits.html

[stretch8668]

Has anyone tried putting this in a 200 http://pages.ebay.com/motors/link/?nav=item.view&id=291107854479 if my math is right that'd make it a 225.52 cc

[Weldangrind]

I think you're right about the final size, and 225cc would be worth it, IMHO. A cool by-product is that you'll have two heads, so you can play with the old one. I'd port the intake side a bit, smooth out the short side radius of the intake and polish the exhaust until it shines.

I also found a kit on Taobao with a 72.5mm bore. That would give you 264cc! http://item.taobao.com/item.htm?spm=a230r.1.14.94.MbZvd3&id=13243492906

[stretch8668]

The question is I wonder if anyone's tried it though if the height of jug is same and the bolt holes are same as the 200cc i might try it when get the money and link is in Chinese

[stretch8668]

From what I'm gathering they share same case and jugs are same length cause the pushrods are the same what I'm thinking on doing is getting the jug and piston plus the 250 camshaft its 150 for bothplus shipping here's link http://www.chinesemotopartsonline.com/250cc/dirt-bike-parts/engine-parts_c112/zenid/33219c65fd2f4e9454f391c953305b92

[Weldangrind]

I haven't actually tried to install a larger jug on a 200, but I have 200 and 223 motors laying around. If you need some specific measurements, just let me know.

I'm inclined to agree with you, although I'm not positive if the FOA (frame of architecture) is identical from 125cc to 223cc. If it is, that means that the rod length is different for each stroke, or the piston pin height is different for each bore. I'd sure like to know. My uneducated guess is that 125 and 150 are one family, and 200 and 223 are another.

If you move forward, please take many pics, and measure the rod length, bore, stroke and cylinder height on whatever you have your hands on.

[stretch8668]

Found out bore and stroke is 67x65 and pushrod 200 is 63.5x62.2 I know the cranks are different and can't figure out if connecting rods are different wrist pin diameters and the bolt hole pattern. Still need to found out about cylinder height I'm still assuming there the same as both use same push rods. Found the height of jug sticking outta motor is different 78.74mm on the 250cc and 76.39 on the 200cc

[Weldangrind]

I'm betting that the wrist pins are the same diameter. Not surprised by the jug height difference.

[pete]

Free shipping too.

Web site looks a little dubious though. The pop ups were in Russian.

I have had no probs with them...
but there shiping is very slow..... yer think you have been ripped off
then it turns up.... one item took 6 weeks to arrive... but free shiping
so I surpose yer can't realy grizzle to much..

[stretch8668]

It would b nice to have the 250 jug on a 200 but hard to tell if it'd fit with out physicaly having both of them side by side and I don't think it'd have enough compression to run with it being taller then 200 jug

[Weldangrind]

Why not change the crank at the same time, and maximize displacement?

[Weldangrind]

This makes me giggle: http://item.taobao.com/item.htm?spm=a230r.1.14.94.MbZvd3&id=13243492906

[stretch8668]

It'd be $373 for crank and connecting rod, jug, head and cam that's if it bolts up to the case plus studs/bolts still cheaper then new 250 motor though as cheapest I've found is 600 plus shipping also don't know interchangeability of zhong and lifan parts

[Weldangrind]

It's not Zong vs. Lifan if it's the same family. IOW, if you're buying parts to convert to a CG250 (as it is referred to), it doesn't matter who the manufacturer is.

[stretch8668]

That's good to know ill have to research it further when need rebuild and have money to do it

[alex_in_az]

I found this one that looks like everything to convert a 125 to a 200. the price on it looks to be 420 yuan plus shipping. that is ~$67 US, or am I crazy? http://item.taobao.com/item.htm?spm=a230r.1.14.38.qSGnR5&id=12769259977
(http://item.taobao.com/item.htm?spm=a230r.1.14.38.qSGnR5&id=12769259977)

[humanbeing]

http://item.taobao.com/item.htm?id=8432093238 (~12kg | Mainland: +60RMB(ground)/+130RMB (air) /Taiwan +300 RMB)

A Taiwanese fitted those 200 (their law are strict on engine's serial #, so...)
http://family.saycoo.com/forum.php?mod=viewthread&tid=269889&page=1&authorid=176114

[Weldangrind]

I found this one that looks like everything to convert a 125 to a 200. the price on it looks to be 420 yuan plus shipping. that is ~$67 US, or am I crazy? http://item.taobao.com/item.htm?spm=a230r.1.14.38.qSGnR5&id=12769259977
(http://item.taobao.com/item.htm?spm=a230r.1.14.38.qSGnR5&id=12769259977)

You're right, but shipping will hurt a bit. Still reasonable.

[Weldangrind]

http://item.taobao.com/item.htm?id=8432093238 (~12kg | Mainland: +60RMB(ground)/+130RMB (air) /Taiwan +300 RMB)

A Taiwanese fitted those 200 (their law are strict on engine's serial #, so...)
http://family.saycoo.com/forum.php?mod=viewthread&tid=269889&page=1&authorid=176114

Thanks for the links. The second link shows some good detail, and demonstrates the cylinder height difference. Looks like a good kit.

[Weldangrind]

Humanbeing, can you help us find a 223 or 230 upgrade kit?

[SpudRider]

...If you move forward, please take many pics, and measure the rod length, bore, stroke and cylinder height on whatever you have your hands on.
X2! :tup:

[stretch8668]

Kinda off topic but has any one thought bout putting the 250 cam in a 200

[bogieboy]

i doubt that theres much difference between the two on a pushrod based engine.... now the real question would be if you could regrind the cam lobe to be more agressive... not sure if it could be done though...

[Weldangrind]

I also doubt that the cam is any different, but I intend to measure them when I have the chance. You could certainly have the existing cam reground to have higher lift, but it's difficult to regrind much more duration. The good news is that you don't have to worry about overlap or lobe separation angle, because there is only one lobe.

[bogieboy]

agree... you could easily add in more lift by reworking the base circle of the cam, although doing that you could work in more duration... smaller base circle, flatten the lobe down a bit...not as much gain in lift as could be had but more duration could be had if you really wanted it...

[stretch8668]

After a lil research I found out the chinese cg125, cg200 and cg250 have same case (correct me if I'm wrong) the difference is displacement still wondering if the jug piston and head would fit on the 200.weldangrind have you taken any measurements yet.

[Weldangrind]

I have not. What specific measurements are you looking for?

[stretch8668]

It wouldn't work unless did crank and connecting rod as the wrist pin on 250 is 1mm lager.I'd have to get crank as well and don't plan on separting case didn't. I was hoping on just changing jugs piston and head but the wrist pin won't fit connecting rod