Piston problems

Xboxbum

New Member
Joined
Apr 11, 2017
Messages
17
Hello everyone need some help here .Ok so i decided to redo the top half of my motor,becase a corborator misshap order new jug and piston plus .Now my piston is passing the deck hight and toping out hitting the head .What am i doing wrong anyone help plz
 


crassius

Well-Known Member
Joined
Jul 23, 2012
Messages
4,572
there are two different kinds of piston and a lot of different barrels (if you count port mapping diffs)

there are threads here about that, or mzmiami has pics that show where to measure the piston

why not reuse the old set?
 

MotorBicycleRacing

Well-Known Member
Joined
Jul 3, 2008
Messages
2,344
Hello everyone need some help here .Ok so i decided to redo the top half of my motor,becase a corborator misshap order new jug and piston plus .Now my piston is passing the deck hight and toping out hitting the head .What am i doing wrong anyone help plz
If you had of compared the new piston to the old piston you might have noticed that they were not the same.
That is the crux of your problem.
The solution would be to buy the same piston as what you were replacing.
Your motor uses a high wrist pin hole piston but you installed a low wrist pin hole piston.
Also the wrist pin from your old piston is a little shorter.
Both 47 mm pistons use the same rings.
 

Xboxbum

New Member
Joined
Apr 11, 2017
Messages
17
If you had of compared the new piston to the old piston you might have noticed that they were not the same.
That is the crux of your problem.
The solution would be to buy the same piston as what you were replacing.
Your motor uses a high wrist pin hole piston but you installed a low wrist pin hole piston.
Also the wrist pin from your old piston is a little shorter.
Both 47 mm pistons use the same rings.
If you had of compared the new piston to the old piston you might have noticed that they were not the same.
That is the crux of your problem.
The solution would be to buy the same piston as what you were replacing.
Your motor uses a high wrist pin hole piston but you installed a low wrist pin hole piston.
Also the wrist pin from your old piston is a little shorter.
Both 47 mm pistons use the same rings.
you would think that they are different but both pistons are the same .both are low ???
 

HumanPerson

Well-Known Member
Joined
Oct 12, 2019
Messages
1,843
did you even put the base gasket back on? check that and report back.
someone here will be able to help ;)
 

Xboxbum

New Member
Joined
Apr 11, 2017
Messages
17
there are two different kinds of piston and a lot of different barrels (if you count port mapping diffs)

there are threads here about that, or mzmiami has pics that show where to measure the piston

why not reuse the old
did you even put the base gasket back on? check that and report back.
someone here will be able to help ;)
did you even put the base gasket back on? check that and report back.
someone here will be able to help ;)
It's a pk 80 engine all gasskets are on gonna order a new piston any segstions where to get?
 

Xboxbum

New Member
Joined
Apr 11, 2017
Messages
17
Its a pk 80 motor i pretty shure the piston is off .anu suggestion where to get a goid piston that relatively cheep?
 
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