Jump to content

Yz125 engine code or year

Recommended Posts

Here's the Casting stamp to determine the year model of the cylinder and head . The first 3 digits determine the year model the rest is production line order etc. The stamps on the head are on the top. On the cylinder, it's found where it says the capacity of the engine i.e. 124-cc stamped on the side.

97 & 98- Head: 4SS, Cylinder: 4SS.

Cylinders run a open water jacket on the base. The coolant hose fitting on the head is located on the rear, next to where the bracket bolts onto from the frame. These models ran a male type expansion chamber with o-rings on the outside. They fitted inside the exhaust port of the barrel. More basic powervalve design.

99- Head : 4JY, Cylinder : 5ET.

Cylinder runs a split water jacket on the base. Power valve shape slightly changes to and oval shape. The coolant hose fitting on the head is located on the rear, next to where the bracket bolts onto from the frame .Expansion chamber changed to a female fitting with o- rings on the inside. Slid over the male exhaust port, which is the same to 2004.

2000 - Head: 4JY, Cylinder: 5HD.

Powervalve shape changes again, more to a rectangular shape with a circular stop. The coolant hose fitting on the head is located on the rear, next to where the bracket bolts onto from the frame. Runs a different base gasket, looks like with rubber lips for better sealing.

2001- Head : 5MV, Cylinder: 5MV

Pretty much the same as the 2000 model. The head design changed. The Coolant hose fitting moved from the rear next to the bracket to the front. Head stud pattern on the barrel had to change to suit the new head design for the coolant hose new routing.

This design was the same up to 2004.

2002 - Head : 5MV, Cylinder :5NY

2003 - Head : 5UN, Cylinder: 5UN

2004 - Head: 5UN, Cylinder : 5XE

-Street_Kleaver

this may help a little depending on how new your bike is, and not to sure if these numbers vary for uk models, was worth a shot though, good luck:thumbsup:

  • Like 2

Share this post


Link to post
Share on other sites

look at your vin# and the tenth digit in the vin is the year of your bike for example if a vin was A1TR3ETGM5IH5FV it would be 2005

Share this post


Link to post
Share on other sites
Here's the Casting stamp to determine the year model of the cylinder and head . The first 3 digits determine the year model the rest is production line order etc. The stamps on the head are on the top. On the cylinder, it's found where it says the capacity of the engine i.e. 124-cc stamped on the side.
97 & 98- Head: 4SS, Cylinder: 4SS.
Cylinders run a open water jacket on the base. The coolant hose fitting on the head is located on the rear, next to where the bracket bolts onto from the frame. These models ran a male type expansion chamber with o-rings on the outside. They fitted inside the exhaust port of the barrel. More basic powervalve design.
99- Head : 4JY, Cylinder : 5ET.
Cylinder runs a split water jacket on the base. Power valve shape slightly changes to and oval shape. The coolant hose fitting on the head is located on the rear, next to where the bracket bolts onto from the frame .Expansion chamber changed to a female fitting with o- rings on the inside. Slid over the male exhaust port, which is the same to 2004.
2000 - Head: 4JY, Cylinder: 5HD.
Powervalve shape changes again, more to a rectangular shape with a circular stop. The coolant hose fitting on the head is located on the rear, next to where the bracket bolts onto from the frame. Runs a different base gasket, looks like with rubber lips for better sealing.
2001- Head : 5MV, Cylinder: 5MV
Pretty much the same as the 2000 model. The head design changed. The Coolant hose fitting moved from the rear next to the bracket to the front. Head stud pattern on the barrel had to change to suit the new head design for the coolant hose new routing.
This design was the same up to 2004.
2002 - Head : 5MV, Cylinder :5NY
2003 - Head : 5UN, Cylinder: 5UN
2004 - Head: 5UN, Cylinder : 5XE
-Street_Kleaver
this may help a little depending on how new your bike is, and not to sure if these numbers vary for uk models, was worth a shot though, good luck:thumbsup:

Can 4jy head fit 03 5un cylinder

Share this post


Link to post
Share on other sites
22 hours ago, Knk9boot said:

Can 4jy head fit 03 5un cylinder

They both share the same O-rings, studs, and number of fasteners...

https://www.partzilla.com/catalog/yamaha/motorcycle/2003/yz125-yz125r/cylinder-head

https://www.partzilla.com/catalog/yamaha/motorcycle/2000/yz125-yz125m1/cylinder-head

Aside from the different coolant hose inlet position, it should work.

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×