257cc linhai/clone valve adjustment. This is one of the best documented and pictorials of this engine you will ever see and on this tutorial the scooter is the Roketa 250B but this valve adjustment on this engine is the same no matter what

scooter it is in. It will also do for the larger 300cc engine as well. Here are the steps I followed to adjust my valves: Important: The engine has to be completely cold.

Remove the seat, rear storage, rear body panel and the battery:

Remove black plastic that holds the battery and fits under the seat. (4 - 10mm screws I think).

I then removed the left and right lower panels and removed the 2 screws holding the bottom panel:

It should hang to give you access to the bottom area:

Access the valves: You should be able to see the top valve door:

Remove the two screws to get to the valves (8mm socket):

From the bottom of the scooter access the lower valve door (8mm socket & 8mm wrench): Some oil

will drip when you remove the cover.

I removed the black plastic cover of the CVT case to access the nut to turn the engine using a 19 socket (3 phillip screws).

It's also recommended to remove the spark plug to make it easier to turn the engine. Set the Top Dead Center: My experience has been to align the timing chain with its mark first.

You need to remove this cover: (Remove the 2 screws holding the cover)

Then align the mark that's located in the timing chain sprocket (see below):

Next check to see if the alignment mark that's located above the oil fill is also aligned. If it is not, then give the engine a complete turn until the timing chain mark is aligned again with its

mark. Check again until both marks are aligned. On my scooter it took 3 turns to get both marks aligned at the same time.

You can see the mark aligned with the side of the hole:

Once the marks are aligned, then use a feeler gauge to measure the gap like in this picture (posted by

bigguy):

Here are the steps to adjust the valves:

Now the intake valve is .004" and the exhaust is .005" and tighten the nut to 14Nm or 10.3 ft lbs.