Piston Rings Turning

[909]

There was no wear or scuffing on any of the good pistons to indicate a lack of lubrication, so I think the mix was OK.

The wear was on the bad pistons though. I have never ever seen this happen on a proper lubricated engine, where 1 side of a piston just happens to wear like that. Either the lack of lubrication wore it or something else is out of spec. I'd look into it though.

[Ruko]

Even on the pistons which had the rings break there was no sign of wear just the scoring from the broken ring. I don't see how it could be a lack of oil as I was mixing the 100-1 Opti at 58-1 so it was almost double the oil it called for. Also the third engine this happened to was running Amsol 2000 at 50-1 just as it calls for. So it happened with 2 different oils mixed at 2 different ratios.

Also as far as excessive wear, while it is possible with mine and the third engines, the second one was on a new machine, only 6 months old, with only about 30-40 hours on it and it had never been apart. He was also running Opti at 58-1 (almost double what it called for).

I know another guy up here who has run Opti at 75-1 for the past 6 years and has never had a problem and has never been into his engine for any reason.

 

So it just doesn't add up for me

 

new machine at 58-1 and wears out the locater pin after 40 hours

different machine running 75-1 for 6 years with no problems.

 

Because of this I don't belive it was a lack of oil problem, I also don't see how a new machine could have excessive clearance after 40 hours.

 

I don't mean to sound ungrateful for all your help and suggestions, but no explaination seems fit all three cases.

 

I know this is a tough one. It has us stumped as well as the local shop here in town.

 

Thanks again for all your help

[Yaxy]

This issue of a turnign ring has been common on Wiseco pistons. I have several friends that only use Wiseco and they always seem to have the same problem (Banshee, 250R) of the pins falling out. This was about 5 years ago and I hope Wiesco has fixed the problem by know but maybe not.

 

I don't think the mixing ratio has anything to do with the pin falling out since they are pressed in. The issue of oil is more towards crank bearign and rod life.

 

I run 40:1 Yamalube R and it worsk great . I get 6 years out of set of piston and I ride about 2000 miles (hard a year) high speads, trails etc. motocross occasionally

 

I have the original crank in my 89 banshee and only replaced the two outer bearigns on the crank because after 11 years I decided to take my cases apart for the first time and changed them and trued the crank. My 89 shee is only 40 over is on its second hone and is within tolerance. I run the bike two years and re-ring twice and then bore and I get very littel if any wear on the pistons and the sleeve. My compression never changes from fresh rebuild to 2 years later.

 

I personally wouldn't run leaner than 50:1 and my bike has proved it works for me.

 

Chris

 

89 shee, Ohlins all around, FMF Pipes, 28 FS Carbs, V-Force, LSR +1+1, PSI MX port, V-Force and Prodesign everything.