Gio x31 2010 piston/bore size?
 

HEY! i'm new to china riders... and i'm french i`m form Quebec/Canada. And i ride a lot of dirt bike. I have a cr 80 and MXR 125cc.

Yesterday someone sell me a gio x31 2010 and the gio as no compression.The bike cost me 275$ :) . No compression = used piston ring? So i want to know what is the bore size of the x31 2010. This morning i call my local china dirt bike seller and he said its 67mm. Is that right?

And i will put a new piston too...

Thx btw sorry for my poor english.

Have a good day.

Dont forget about the valves in your quest for compression

i would check the valve lash first, and then pull the head and actually measure the bore... the cases on my Shineray would indicate by thier model number that i had a 69mm bore, but i had a 63mm... so your best bet is to actially measure it rather than go off someone elses word...(like "oh it lost spark" baloney,you fried the piston rings you lying sack of ****) but yeah....LOL never trust someones word on a china bike...

Bienvenue! :hi:

I agree that you should check the valves to make sure they are not too tight. Do you have a picture of the engine?

Thx i will post pic of the valve staturday. The seller said the bike take a lot of oil and after start loosing compression and the motor not running. So i order 67 mm piston and ring... do you think i will need a refund because the local shop dont give me the true information?

And yes i will check the valve but and dont know... its my first 4 stroke.

Btw thx for the reply your great!

Well, if its a valve adjustment or a bad piston, both of those would cause the symptoms that they described of no compression. If the valve lash it too tight the valves could be slightly open yet, causing the air and gas to go right out, and not build compression, or your rings could be fried, like mine were, and then you get a lot of blowby past them, and they dont scrape down the oil propey, and it burns more oil....

Thx bogieboy, so first of all ring are fried so new ring for sure... and valve are probably to tight, how you know is to tight... i need ajustement tool?

We can show you how to set your valves after you show us a picture of your motor. We need to know which type of motor.

There is a number next to the gearshift. What is that number?

ok thanks i will buy some valve gauge tappet is it neccessary?

You will need a set of feeler guages, or you can get it darn close by eyeballing it...LOL not reccomended though... Then again thats what i did...LOL you should feel just a tick of play (a few thousandths of an inch) on the rocker, if its gor no play, its too tight, if you can see the play its too loose... You want to feel just a tick of play and not really see any movement...LOL if that makes sense... I believe the proper spec is .004 feeler gauge? Someone else can verify that...

nlet 0.05mm / 0.002in, and;
Exhaust 0.08mm / 0.003in

Correct?

I would think thats about right...im too lazy to try and find my feelers so i always just set it by feel...LOL

IN/EX 0.08mm is the recommended spec for CG125 (Chinese engine inspired by that design also using that spec )
IN/EX 0.10mm is the recommended spec for MD33 (the "223"/ OHC)

Lol who's right its .10mm? in/ex or .05mm and .08mm??

Honesltly i think any one of the specs works fine, seeing as i dont even use the feelers and my engine runs strong....LOL