Browse Category: Pistons & Cylinder

Cylinder in place

The difficult job is done, got the cylinder block down onto the pistons without breaking any of the piston rings. Got a helping hand from a friend, was too scared to do it alone.




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Hmm, rusty bolts. A new kit has been ordered from UK. The attempt to refurbish the old ones was not a success. Let’s hope I soon get the parts and can mount the cylinder head the next weekend.

Installing pistons

New parts to be mounted


Part no


Step 1: Circlip


Mount one circlip in all three pistons. Move the end position away from the cutout. Be gentle and don’t bend the circlip too much. Use a screw driver as a tool to flip it into the position in the groove. Always new circlips, never reuse old one.


Step 2: Piston rings

Piston rings

Mount the piston ring as shown on the photo. Be aware of the pin locking the ring, see the arrows. You don’t need any special tools for mounting the piston rings. They are quite expensive an if you are afraid of braking any of them, drink a beer before you start 🙂

Step 3: Gasket and O-rings



Mount the gasket, don’t forget to mount three O-rings underneath the gasket.



Before you continue, cover all holes so you don’t drop any parts inside the engine. Can be difficult to retrieve.


Step 4: Pistons



Oil the bearing before and after it’s installed in the rod.

Piston mounting

Remeber the washers (31)




Push in the piston pin and mount the last circlip at the end.




Make sure the right piston (label R) is on the right hand side and the arrow is pointing forwards. The left and center piston are identical and are both labeled L

Powder blasting of the cylinder

I got hold of a “new” cylinder for my bike. Seems to be in a good shape but is full of old burned oil. Not easy to clean. Can the powder blasting do the job ? Lets try ! The powder is ordinary baking soda and will not do any harm to the cylinder.

Click on the images for a close-up view.

Before the powder blasting:

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 After the blasting:

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Drying up after a wash with water and soap. A layer of WD40 inside the cylinders.


I’m very pleased with the job. Nice and clean, like a new one from the factory.