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Clubroom => Tech Talk => Topic started by: Kenneth S (222) on June 14, 2012, 07:20:57 pm

Title: Top ring jammed into slot on new Wiseco Piston??
Post by: Kenneth S (222) on June 14, 2012, 07:20:57 pm

Hi Guys,
Just putting new rings into my RZ and the top ring was solidly jammed into the groove at the front of the piston. The piston is definitely not hitting the head, its seems untouched but at the front of the piston, the top groove is visually smaller than the bottom groove and visually smaller then the same groove at the back of the piston. I have not seen this before except when water got into the engine but not this time. There seems a little bit of a lip on the leading edge of the piston, I can only imagine it is collecting the top edge of the exhaust port on the way up.

My solution would be to take the edge off either the top of the exhaust port or the top of the piston.

Anyone had this happen? Comments?

Title: Re: Top ring jammed into slot on new Wiseco Piston??
Post by: Noel on June 14, 2012, 08:03:36 pm

chamfer the ports ,Use more oil. ;D
Noel

Title: Re: Top ring jammed into slot on new Wiseco Piston??
Post by: suzuki27 on June 14, 2012, 08:16:06 pm

Yer, chamfer the offending port edge and use more lube.

Title: Re: Top ring jammed into slot on new Wiseco Piston??
Post by: Lozza on June 14, 2012, 08:57:54 pm

Any detonation?

Title: Re: Top ring jammed into slot on new Wiseco Piston??
Post by: ola_martin on June 14, 2012, 09:34:25 pm

I've had several problems with Wiseco with the locatingpin for the ring just sliding into the piston, and the ring turning until it caches on a port.
Several 85 and 125's.
I have cut the pinhole open and found that the hole is drilled too deep, allowing the pin to go in when the piston is hot enough.

Title: Re: Top ring jammed into slot on new Wiseco Piston??
Post by: Kenneth S (222) on June 14, 2012, 09:55:06 pm

Quote from: Lozza on June 14, 2012, 08:57:54 pm

Any detonation?

Heard it but don't now what it means. What am I looking for?

Title: Re: Top ring jammed into slot on new Wiseco Piston??
Post by: Simo63 on June 14, 2012, 09:57:03 pm

You can chamfer the ports as suggested but you should also chamfer the ring groove slightly.  If you haven't done this before you should get someone who has to help you Ken.  The idea is that it stops the metal just burring over the ring and holding it into the groove.  I used to this all the time on my RS125, if you didn't the ring would invariably get stuck in the groove at the front of the piston.

Cheers
Craig

Title: Re: Top ring jammed into slot on new Wiseco Piston??
Post by: Simo63 on June 14, 2012, 09:57:41 pm

Quote from: KJ222 on June 14, 2012, 09:55:06 pm

Quote from: Lozza on June 14, 2012, 08:57:54 pm

Any detonation?

Heard it but don't now what it means. What am I looking for?

A light grey "burn" ring around the top rim of the piston

Title: Re: Top ring jammed into slot on new Wiseco Piston??
Post by: Lozza on June 14, 2012, 10:05:40 pm

Pock marks and a sandblasted look to te crown.

Simo the RS traps rings with and alarming regularity all traced to carburation, V-ing out the ring groove helps but te 0.7mm ring fixes the issue , just gets more oil.

Title: Re: Top ring jammed into slot on new Wiseco Piston??
Post by: Kenneth S (222) on June 15, 2012, 05:00:32 am

Thanks guys, no signs of detonation at all. I'd be surprised if it is an oil issue, I don't run the ratio that lean and there seems to be a healthy film of oil allover when I pull it down, I think it is more mechanical with the leading edge of the piston nicking the top edge of the exhaust port.

I'll chamfer the top of the port and the ring groove and go from there.