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Kai.Wilson
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Joined: 26 Sep 2009
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PostPosted: 19:08 - 23 Aug 2013    Post subject: CG Big Bore Reply with quote
Evening all.

Before you all say, I know I wont see a lot of differance etc, just basicly because im gonna have to pay £20 to remove a broken stud may aswell upgrade.

Just wanna know if this 200kit will fit a 125 engine:

https://www.ebay.co.uk/itm/Cylinder-Big-Bore-Kits-for-Honda-CG-200-Pit-Bike-Moped-ATV-196cm3-/271263369125?hash=item3f288e87a5

Cheers all
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UnspeedySam
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Joined: 26 Nov 2009
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PostPosted: 20:12 - 23 Aug 2013    Post subject: Re: CG Big Bore Reply with quote
Kai.Wilson wrote:
Evening all.

Before you all say, I know I wont see a lot of differance etc, just basicly because im gonna have to pay £20 to remove a broken stud may aswell upgrade.

Just wanna know if this 200kit will fit a 125 engine:

https://www.ebay.co.uk/itm/Cylinder-Big-Bore-Kits-for-Honda-CG-200-Pit-Bike-Moped-ATV-196cm3-/271263369125?hash=item3f288e87a5

Cheers all


As far as I know, the answer is no. The stroke on these is longer than on the standard CG125 motor. The biggest you can take a CG125 motor without major work is 150 if I remember correctly. I'll back this post up with actual evidence as I find it...

edit: Information: https://hondacg125.awardspace.com/how_to_increase_engine_size.htm

CG125 Bore x Stroke 56.5 x 49.5 mm
CG200 Bore x Stroke 63.5 x 62.2 mm

You can probably buy a CG200 engine and bolt it straight in though...that might be your best bet.
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Riding: BMW R1150RT `02 bought mildly crashed
Fixing: Also the BMW as I get less broken bits
Gone: ZZR600 '00, TRX850 '97, RXS100 '93, JS125-6B '07, BMW R1100RS '93, Kawasaki ZX-6R-J2 '01, Honda Bros NT400 NC25 '88
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Kai.Wilson
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Joined: 26 Sep 2009
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PostPosted: 21:01 - 23 Aug 2013    Post subject: Reply with quote
As the cg125 cast iron liner is only 71mm in outer diameter,
boring out to 61mm or even 63mm leaves little in the way of metal behind and would probably fail.


And the 200cc kit is 63.5mm

Dunno if I should risk it hmm
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UnspeedySam
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Joined: 26 Nov 2009
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PostPosted: 21:04 - 23 Aug 2013    Post subject: Reply with quote
Kai.Wilson wrote:
As the cg125 cast iron liner is only 71mm in outer diameter,
boring out to 61mm or even 63mm leaves little in the way of metal behind and would probably fail.


And the 200cc kit is 63.5mm

Dunno if I should risk it hmm


The issue is the stroke is also longer which means you'd have to rip apart the bottom end and replace the con rod. You would also need to bore out the crank case mouth. It's not worth the hassle, even if you can get it to work...trust me!
____________________
Riding: BMW R1150RT `02 bought mildly crashed
Fixing: Also the BMW as I get less broken bits
Gone: ZZR600 '00, TRX850 '97, RXS100 '93, JS125-6B '07, BMW R1100RS '93, Kawasaki ZX-6R-J2 '01, Honda Bros NT400 NC25 '88
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UnspeedySam
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Joined: 26 Nov 2009
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PostPosted: 21:06 - 23 Aug 2013    Post subject: Reply with quote
Also read this thread. https://www.bikechatforums.com/viewtopic.php?t=231057
____________________
Riding: BMW R1150RT `02 bought mildly crashed
Fixing: Also the BMW as I get less broken bits
Gone: ZZR600 '00, TRX850 '97, RXS100 '93, JS125-6B '07, BMW R1100RS '93, Kawasaki ZX-6R-J2 '01, Honda Bros NT400 NC25 '88
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The other Paul Rudd
Scooby Slapper



Joined: 06 May 2013
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PostPosted: 11:15 - 24 Aug 2013    Post subject: Reply with quote
UnspeedySam wrote:
The issue is the stroke is also longer which means you'd have to rip apart the bottom end and replace the con rod. You would also need to bore out the crank case mouth. It's not worth the hassle, even if you can get it to work...trust me!


You'd have to replace the crank with the longer stroke 200 one, and they're probably not that common as when have you ever seen a 200cc Chinese bike over here.

If replacing the stud is £20 I'd just go with that.
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sickpup
Old Timer



Joined: 21 Apr 2004
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PostPosted: 01:18 - 25 Aug 2013    Post subject: Reply with quote
Kai.Wilson wrote:
As the cg125 cast iron liner is only 71mm in outer diameter,
boring out to 61mm or even 63mm leaves little in the way of metal behind and would probably fail.


And the 200cc kit is 63.5mm

Dunno if I should risk it hmm


Even on an air cooled bike a 3.75mm wall thickness on the barrel should be more than enough to resist warpage unless you are in the habit of leaving the bike idling for long periods.
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Kai.Wilson
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Joined: 26 Sep 2009
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PostPosted: 03:41 - 25 Aug 2013    Post subject: Reply with quote
Just a shame it's not a bolt on set up and ride product, would imagine this would bring a good amount of power to the CG
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pepperami
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Joined: 17 Jan 2010
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PostPosted: 11:54 - 25 Aug 2013    Post subject: Reply with quote
The other Paul Rudd wrote:

when have you ever seen a 200cc Chinese bike over here.

.

This for example

https://www.ebay.co.uk/itm/XMOTO-200cc-Scrambler-Adult-Teenager-Size-4-stroke-electric-start-Manual-5-speed-/270730604187?pt=UK_Motorcycles&hash=item3f08cd2e9b

Or this maybe?

https://www.ebay.co.uk/itm/New-200cc-Sportsbike-Sports-Bike-YZF-R-style-Superbyke-RSP-200-250-/121093025463?pt=UK_Motorcycles&hash=item1c31b4eeb7

Wink
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cb1rocket
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Joined: 30 Jan 2010
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PostPosted: 13:14 - 25 Aug 2013    Post subject: Reply with quote
Easier to fit a complete 200cc lump
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Tbag
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Joined: 29 May 2012
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PostPosted: 13:19 - 25 Aug 2013    Post subject: Reply with quote
As far as i am aware, the old XL185 engine will bolt straight in.

You might want to look into the electrical system as im unsure if the 185 was 6v or 12v points igniton.
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pepperami
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Joined: 17 Jan 2010
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PostPosted: 13:50 - 25 Aug 2013    Post subject: Reply with quote
I had an old CG 125 a few years back and thought about upgrading? it.

I had a look for an Xl 185 engine and they are as rare as rocking horse shite.
I believe that the Xl 185 engine is to tall with out a modification?
Don't quote me on that!
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Kai.Wilson
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Joined: 26 Sep 2009
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PostPosted: 14:12 - 25 Aug 2013    Post subject: Reply with quote
Only want a bit of extra poke before i do my full test next year.

Would do it now, but gotta do my car first as me and the missus have just had our first baby and gotta buy a family car - well a freelander which is somewhat manly lol
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