Mitaka Pistons - Which way around to fit?

Kr1s1991h · Post by **Kr1s1991h** » Wed Mar 10, 2010 11:22 pm

Hi all,

Just wondered if there is a correct way to fit the above pistons as they do not have any arrows or marks on to show which way around they should be fitted.

Have noticed there are two holes on each side, these could go nearer the front or back depending on which way you fit them, the ring pegs could face forward or back again depending on which way you fit them.

If it helps i could post a pic tomorrow night.

Thanks in advance!

mj43 · Post by **mj43** » Wed Mar 10, 2010 11:38 pm

Holes to the front, ring pegs to the back.

The ring ends must not run over a port else you will snap a ring.

The exception to this is TZ single ring pistons where the ring end gap is in the boost port.

Post a piccy if unclear

Kr1s1991h · Post by **Kr1s1991h** » Fri Mar 12, 2010 5:56 pm

Thanks for that 'very important' bit of information Mark,
Will make sure they are fitted the correct way round!!

Will upload a pic later on, as it may help others too.

Kr1s1991h · Post by **Kr1s1991h** » Fri Mar 12, 2010 6:36 pm

One more piston related question, i have a pack of genuine piston circlips which are a 'C' shape, however the circlips which came with the pistons are a 'G' shape.

Which of the two types do people recommend using, the genuine kwack ones or the other.

Thanks again....

Tripitaka · Post by **Tripitaka** » Fri Mar 12, 2010 7:35 pm

Wouldn't have thought it makes much difference, the racers probably use the C clip to save weight

The G clip is a little easier to fit and remove if you plan on removing the pistons often.

mj43 · Post by **mj43** » Fri Mar 12, 2010 8:02 pm

What can happen with G clip is the pin wears through the tang that forms the G and it then trashes the engine.

Yam 26J pistons use them and I was advised to trim the tag. The alternative is changing the clip often (less than 500miles). Certainly the tags show wear - I will see if I can dig up some examples.

JanBros · Post by **JanBros** » Fri Mar 12, 2010 11:39 pm

normaly there is always an arrow on top off a 2-stroke piston, and the arrow should always point to the exhaust.

Tripitaka · Post by **Tripitaka** » Sat Mar 13, 2010 8:57 pm

mj43 wrote:What can happen with G clip is the pin wears through the tang that forms the G and it then trashes the engine.

Yam 26J pistons use them and I was advised to trim the tag. The alternative is changing the clip often (less than 500miles). Certainly the tags show wear - I will see if I can dig up some examples.

blimey, never knew that.

Do you trim the tag off completely, making it a C or just cut it shorter than the edge of the pin?

Neil.