Rings

[chopper]

Stab in the dark, but you never know!

I have after a long search and wait got some nos rings for the 250, trouble is im not happy about how the top one sits, got the first set a week or so ago and upon trying to get the upper ring inside the barrel it snapped into 4 pieces (using a ring compressor)! another set came today and again im not happy about how the top sits, the lower ring sits almost flush inside the recess, what i think is how it should be, the upper protrudes more. This is for the newer SX250 nikasil lined barrel that i got with the other engine i bought so im guessing they cant be honed rings are NOS and the correct part number according to the parts list i have?

My 2 stroke knowledge is limited but growing daily so how much should the upper ring protrude!

 

[Limey_Dave]

Re: Rings

Did you fit the rings in the cylinder to check the ring gap,before fitting to piston?
If you're fitting the new piston and cylinder to the original engine,is the piston the right way round?
The ring grooves have pins to stop the rings turning and catching in the ports,if the top ring isn't located correctly with the pin,it could stick out.
If the piston is the wrong way round,even with the ring located with the pin,it could still catch in the ports as you lower the cylinder.

Sorry that's all I can think of,other than contacting Marjo.

 

[Ukkid76]

Re: Rings

There will be a notch in the piston ring grove which could be hard to find if you don't know its there this sits in the gap to keep the piston ring in the correct position,

Another thing to note if you're using new rings and old pistons there will/may be a layer of carbon which has built up in the grove under the old ring, this needs to be scraped out using a grove tool before fitting the new rings, it is passable to use a piece of old piston ring broken off and used as a scraper.... if you have new pistons then ignore second parpgraph......

 

[chopper]

Re: Rings

Thanks Guys, Piston is on the correct way and rings lined up with notches, must admit i havent checked the rings against the cylinder will do that tonight. I think it may be crap in the ring gap as when compressing the ring it does stick slightly on the upper ring, but not the lower, will get in there and clean it up tonight and see how i go. if all else fails ill drop the lot down to a experienced 2 stroke mate of mine at the weekend and see what he can do

 

[Marjo]

Re: Rings

...........
If the piston is the wrong way round,even with the ring located with the pin,it could still catch in the ports as you lower the cylinder.

Sorry that's all I can think of,other than contacting Marjo.

Uhm... I am VERY good at breaking things, especially 2 strokes wasntme: sigh), but I lack technical knowledge
I suggest you contact Huib if you still cant get it the way it should be, Neil. He can help you out, I am sure!

Good luck