frequently asked questions

The information given in the technical support FAQ consists of very general knowledge in engine rebuilding. To retain the best outcome of your engine rebuild, please consult a reputable engine rebuilder to carry out your use of Namura products.

What clearance do I use when installing a Namura piston?

Namura Pistons are manufactured per OEM specs, so in order to confirm the clearance you will need a shop manual to find the appropriate measurements for your bike. Please remember that additional bore clearance may be necessary for modified engines (aftermarket pipes, ignition mods, cast iron bores, etc.).

I have a 2 stroke and the piston has dual rings. Which one goes on top?

The top compression ring will have a silver finish on the outer diameter.

I have a 4 stroke. Where do all these rings go?

Generally, the top compression ring will have a silver finish around the outer diameter; the middle ring will be all black followed by the bottom “oil” ring (which is made up of one expansion ring and two scraper rings). Please consult a professional if you are unsure.

I have this 4 stroke. Now I know where the rings go, so I just line up all these ring gaps…right?

The ring gaps should be staggered 120 degrees apart. Pay special attention to the oil ring; the two scraper rings should be staggered one inch from the gap of the expansion ring (one gap to the right of the expansion ring gap, the other to the left of the expansion ring gap). Please consult a professional if you are unsure.

I see markings on the rings. Does this mean anything?

The numbers or markings on the ring should be facing up when you install them.

Does the coating on the piston affect my piston-to-cylinder clearance?

No, the coating is not a part of the thermal expanding material of the piston and will not affect the piston-to-cylinder wall clearance.

It appears I have extra gaskets in my gasket set. Why?

When company develop company gasket kits company sometimes include pieces that are only used in certain years of the application. Use the pieces that are needed for your specific application, and always consult your service manual if in doubt.