1p60fmj

[spoonta68]

hi im wondering if the yx(gpx 160cc are marked on the head as 150cc or 160cc?
as the 1p60fmj is a model code for both

 

[coolmodee01]

not sure

but they are the same head and barrel

the 160 just has a longer stroke (cant remember numbers)

 

[motorman]

If they are the same head and barrell, then you could pretty much do the same bore kit upgrades then yeah?

I seem to be struggling to find a bore kit which say's it's actually for the YX140 motor.

 

[spoonta68]

the tb 146cc bore kit with 13mm pin fits or u can go all the way to 160 if ya want aswell

case closed saughted out my dillema lol

cheers guys

 

[wogtaz ryder]

dont think u can do the same uprades coz of the different strokes ..

 

[spoonta68]

the same tb kits fit both the 150 and the 160 but u end up with different displacment
example:
same kit on 150 takes to 170cc as the 160 gets taken to 186cc

but on the story of the 140cc u can go pretty high but with the crf50 headstud spacing it gets pretty hairy towards the pointy end of the stick tho lol

 

[motorman]

Thanks Spoonta. Might pick you brain a bit tonight about it all.

 

[spoonta68]

all good bro

 

[motorman]

Would this go alright or am i better of buying a 160 motor??

Honda Trail Bikes

 

[Divy]

hey spoonta,

can you please give me a link to the tb kit that takes the gpx 160cc to 186cc

i would like to know more about it and prices

 

[spoonta68]

Hey mvman
that kit would be off chops as uve got a wicked stroke in the yx140cc's
with that kit ud have a solid package that woudl maul most bike out there give or take mine lol

and divy its actually 184cc but my mistake only .2mm diff lol
Classic Honda 50's Australia - TB 184cc Bore Kit, Race Head V2 and 28mm Carb Kit - GPX-YX160 [TBW9040]

if ya gonna buy a kit then let me know as im in the market aswell and we can maybe get a better deal for 2 or 3

 

[motorman]

^^^^ This site will tell you what you need:

Honda Z50 parts CT70 parts XR50 parts CRF50 parts performance NOS Honda XR50 Z50 Honda minitrail CT70 Honda NOS parts Z50 CT70, Honda trail 50 70 , Honda Z50 CRF50 QA50 XR50 CT70 SL70 XL70 XR75 SL90 ST90 SL100 SL125 SL350 parts

And email these guys for prices:

Classic Honda 50's Australia

 

[NRG]

not sure

but they are the same head and barrel

the 160 just has a longer stroke (cant remember numbers)

Here you go:

Model: 1P60YMJ
155cc oil cooled racing engine

Specification:
Style: Single cylinder, 4 stroke, oil cooled
Displacement: 155.5 ml
Bore x stroke: 60 x 55 mm
Max. Power:10.5 kw/9500 rpm
Rated torque:11.5 N.m/8500 rpm
Start: Kick start, start any gear
Gearbox: N1234 or 1N234
Clutch: Manual, wet, multi-plate
Igntion: CDI
Luburation: Pressure splash
Net weight: 21 kg
Overall size: 470 x 320 x 270 mm

 

[Cactus Jack]

They look like the specs for the 155Z NRG ...

Since you should be the expert on YX/Zongshen motors ... When they vary the stroke ... IF the cylinders are all the same length/height .... do they run different conrod lengths OR different pin heights in their pistons ? ... Also what is your opinion on the 155Z vs YX 150/160's both in performance and reliability wise ? ... It'd be great to hear it from someone who's actively involved at the coal face ...

 

[NRG]

They look like the specs for the 155Z NRG ...

Since you should be the expert on YX/Zongshen motors ... When they vary the stroke ... IF the cylinders are all the same length/height .... do they run different conrod lengths OR different pin heights in their pistons ? ... Also what is your opinion on the 155Z vs YX 150/160's both in performance and reliability wise ? ... It'd be great to hear it from someone who's actively involved at the coal face ...

Damn copy & paste da wrong spec's.............sorry!

Dont know much about the Z155.5 engines as they are not produced by our YX partners although i took a head off one with a bent exhaust valve last week (it was bent from the top, didnt look too much into it so i am guessing that it seized in the guide at some point).
I think we may see more of these as there might be enough tolerance's between the valve guides & the Valves.

Replaced the whole head with a early YX one.......they fit.

Too soon to judge the Z155.5 engine overall, but most diffenately sounds Quiter that the older YX.

As for the Stroke difference's in the 150/160 YX it is done by positioning the Crankshaft "Cotter" pin in a higher spot which gives you the longer stroke.
Conrod, Piston, cylinder are exactly the same.

Check out my cheap YX150 Mod in the next issue 50's Bortherhood.

 

[Cactus Jack]

Yes definitely sounds like the exhaust valve stem seized in the guide ...

I know how cranks are stroked ... The conrod length or piston pin height can't be the same unless the piston sits down the bore by 2 mm in a YX150 ...

ie ... a YX 150 has a 53 mm stroke and YX160 has a 57 mm stroke ... so the crank pin has been moved outwards by 2 mm (increasing the radius by 2 mm increases the pitch circle diameter by 4 mm) ... so the 160's piston goes 2mm higher up the bore AND gets pulled down 2 mm lower giving a 4 mm increase in the stroke and the extra 10 cc ... IF the rod isn't shortened by 2 mm or the piston pin to piston deck height isn't reduced by 2 mm ... the piston will hit the head ...

I'll definitely check out your article when it comes out ... I've got a brand new unrun 2008 model YX150 engine ... do you know if they had the bearing issue ? ... It'd be better to flog it off and get a later model engine with the needle bearing case and shaft rather than pay for the upgrade parts and pull the new engine down ...