Ebay crapshoot rebuild thread

[INTP_ty]

how do I know whether the cylinder I get is the right height? I scored mine & the replacement I ordered is 3mm taller. Bike no go fast.


This is a crapshoot of a crapshoot mix of parts

 

[crassius]

I usually email mzmiami my measurements - not gotten wrong part yet.

 

[INTP_ty]

I usually email mzmiami my measurements - not gotten wrong part yet.

Is he a vendor? Id rather give someone my my engine model (fm80) so the expert can take over. There’s simply not enough information on the Ebay listings

 

[crassius]

most ebay sellers only buy and sell boxes - they have no idea what is in the box and almost everyone makes up names and models that sound good to them. but may be pretty much anything - my boxes of PK80s have (I think), after two changes become A80s (big diff) while still coming in PK labeled boxes

the mzmiami site will answer emails and has some knowledge about which fits what - they are just a parts house

 

[INTP_ty]

FM80 Rod = 38mm / Type B Piston – GT5 Type *

http://pk80engines.com/home/pistons-and-rods/

Does this help?

I am certain that the exhaust port on the cylinder was bell mouthed i.e. not a circle.

The kit also came with a STEEL [explicit] cheap-ass intake manifold. The very first kit I purchased came with an aluminum intake manifold that was bell mouthed. Idk if that helps track down the cylinder head or not...

 

[crassius]

you got one taller, so you need to measure deck height (dist from base gasket surface to head gasket surface) also measure distance from top of intake port to head gasket surface, then check if you need 32mm or 40mm intake stud width

these motors are disposable, so I rarely recommend a rebuild when a whole new one is cheap and usually improved over last year's model

 

[CrazyDan]

these motors are disposable, so I rarely recommend a rebuild when a whole new one is cheap and usually improved over last year's model

If you buy a typical eBay special, then you are buying a model 4+ years old that's been basically discontinued with the overstock sold uber cheap. Expect the old issues to pop up that newer models have fixed. Spend the +-$20 extra for new inventory.