X rage py90 90cc to 110cc issues

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chilliwackwestie

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Hello or should I say G'day
I have a Chinese 90cc 4 stroke mini that I am trying to upgrade to 110cc. I ordered a 110cc barrel and piston kit form china. Everything fits fine except the piston. At TDC the piston comes out of the cylinder by about 1-2mm. Also the piston itself has no valve relief's on it which will cause the valves to contact the piston. My son is quite disappointed he can't ride at the moment.
IS there something IM missing. Can I use a thicker base gasket to make up for the piston height issue or will that mess with the timing chain?
Is there a 110cc piston available with valve relief's ?
X rage is a brand sold here in Canada and it looks quite similar to the Baja brand also sold here.
It looks like the same kind of engine found in a Honda super cub.
Cheers
 
Welcome to Miniriders.


Drop in a say hello in our Introduce Yourself thread too while you're here.


Does the PY90s' engine look like this one ?

$_86.JPG


If so yeah it's a china copy of a Honda 50cc based horizontal engine, like in the CRF50's, CT110's etc
Is the engine model number something like 1P47FMF ?
It's stamped into the engine case above the l/h foot peg mount / below front sprocket
If it is it'll have a 47mm bore and 49.5mm stroke.

The kit you bought, do you have a link to it ?
It would use a 52mm piston/cylinder i'm guessing ?


Cheers, Craig
 
Ok, compare the dimension's of your original cylinder/piston with these

Measurement mm inches
Skirt Length 23.5 0.93
Outer Diameter of Skirt 56 2.2
Bore Diameter (bottom end) 52.4 2.06
Bore Diameter (top end) 52.4 2.06
Dimensions of Timing Chain Slot (width) 17 0.67
Dimensions of Timing Chain Slot (length) 63.5 2.5
Barrel Length (including skirt section) 93 3.66
Diameter of Oil Port Hole 10 0.39
Upper Piston Diameter 51 2.01
Lower Piston Diameter 52 2.05
Centre of Pin Hole to Crown 19 0.75
Piston Height 37 1.46
Crown Height 37 1.46
Gudgeon Pin Diameter 13 0.51
Gudgeon Pin Length 41 1.61
 
So would the issues im having be because the actual cylinder deck to deck is to short? The original piston was domed and had valve relief in it. Where the new kit is a flat top With a small dish in the Middle. Do i need a different cylinder head for the 110 ?

Are there any online resources that will make identifying the correct parts for this engine. And the correct upgrade parts. I would like to get this thing to 110cc the 90 is doing well but we linve in the mountains and my son likes to climb hills
 
Last edited:
hope this helps u

Hello or should I say G'day
I have a Chinese 90cc 4 stroke mini that I am trying to upgrade to 110cc. I ordered a 110cc barrel and piston kit form china. Everything fits fine except the piston. At TDC the piston comes out of the cylinder by about 1-2mm. Also the piston itself has no valve relief's on it which will cause the valves to contact the piston. My son is quite disappointed he can't ride at the moment.
IS there something IM missing. Can I use a thicker base gasket to make up for the piston height issue or will that mess with the timing chain?
Is there a 110cc piston available with valve relief's ?
X rage is a brand sold here in Canada and it looks quite similar to the Baja brand also sold here.
It looks like the same kind of engine found in a Honda super cub.
Cheers

hi I buy all my parts from here https://www.pocketbikeparts.com/ never had a problem with them and they sell 90cc to 110cc kits
 
Hi could you please tell if a zq147fmf is the same an where’s the best place for stock cylinder and piston thank you in Advance
 

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