Hello everyone,
I have been battleing my girlfriends 86 250R for some time now and to be honest I am about to sell it and get a 4 stroke. Last year she fried the top end riding it down in Sand Lakes OR and we recently got the jug punched out to a 265. The other day while completing the break in process she fried the rings again on the new Weisco Pro light piston that I installed. This bike is far from a racer and all I want is reliability out of it. What brand piston and rings should I go with to minimize this? I hear Weisco is good for racing but do not have that great of life span?

P.S. Yes I went extra rich on the jetting and the plug looked fine

Thanks,
Brad

 

theres a huge aftermarket for the 250r and how was she riding it to break it in? try www.esr250.com they have alot of products for it and a piston.

 

I have a feeling your not breaking it in correct how are you doing it?

 

Well when I got the jug back I checked the ring clearances and then coated the inside of the cylinder walls with some 2-stroke oil and also put some on the piston skirt and rings. After I got the jug back on, everything was toured down to spec and I started the heat cycles.

Started the bike and reved it from idle to slightly above idle until the outside of the cylinder wall was too hot to touch (about 3 or 4 minutes). Once the cylinder was too hot to touch I let the bike cool all the way down and then started over again. At this point I also re-tourqued the cylinder also. After this was done about 4 or 5 times I started to ride the bike, going through all gears but only to about 3/4 throttle. After this was done for a solid 4 or 5 hours, it was time to lay into the throttle. All was going great for about 2 hours and then bam, nothing. No more compression, I have not had a chance to pop the top end off yet to see exactly what went wrong but I followed the break in I was given to the T and it still failed on me. Pulled the plug out and it was a nice coffee with cream color and I even went a little richer then normal on the jetting. Any thoughts or suggestions?

Thanks,
Brad

 

sounds like its still running lean if it was a coffee cream color. when ur doing break in mix extra oil into it but leave teh jetting u have.

 

I stuped up the jetting on this bike for this rebuild, my girlfriends Ex was running a 165main with a 42 pilot which was WAY WAY too lean. I jumped all the way up to a 185 main with a 48 pilot and it ran much better and then took a the big crap on me. I have always used Wiseco pistons in all my toys and to be honest I have not had very good luck with them over the years. I am thinking about switching brands to maybe a Vertex but I have not found the model that I need for this bike. They claim faster break in time, and also longer life. This Wiseco is a 68mm Pro Light. Does anyone out there run a different brannd piston other then Wiseco?

 

Why would you leave the jetting the same but mix in extra oil?
That would LEAN out the bike. (not good for break in)

Extra oil is taking the place of fuel... and you have a leaner, hotter burning mixture.

 

not really u mix an extra ounce of oil for every gallon which allows for more lubrication on the new piston

 

mybe the guy you bought it from did a 89 rod conversion and you are using an 86 piston and it is slapping the head. you mean BAM, no compresion...like the plug is gone no compresion, or somthing broke bam no compresion.

 

I am pretty sure the bottom end has not been touched (86). The bike ran great for a few weeks until we started to get on the throttle a little more so you would think that an 89 rod conversion the bike would never have started in the first place but thats a great thought. When it took the dive, it was almost like it ran out of fuel or someone had hit the off switch, I am sure the rings are the fried, I just hope my brand new bore job is not too messed up. Also, just last night I found out that the premix used in it was Powerpunch mixed at 35:1. Does anyone out there have a preference over Weisco Pro Lights?