Is it not supposed to be mixed at 20:1????? that is what the factory mix is, but i am not sure if it will be different with the mods.

There is only one reason why it would burn up a set of rings..... not enough lube.

 

Well, It probally should have been lower then 35:1 with that crap Powerpunch but talking with other people and also Bel Ray, they suggest 50:1 with MC1.

 

50:1 holy poo........ regular 2 stroke oil at a 20:1 mix would probably have done it till it was all broken in. I am looking at purchasing a 250R real soon, and it too has an engine problem. let me know if you find the right mix.

Wiseco pistons seem to be really popular and they have a good product, I honestly think it was a mix problem.

 

The 250R does call for a 20:1 ratio.

 

20:1 was back in 1986, bone stock, with old types of premix, This 250R is far from stock. Everyone I know that has similar mods done runs anywhere from 40:1 to 50:1.

 

What did the piston look like and also the sleeve after it blew up again? Also, did it sieze or just lose compression?

 

First things first. You may have a air leak somewhere causing the motor to lean out. Of course right now you are just speculating you fried another piston. Assuming you did, if the motor has an air leak, it can cause a lean condition and fry your piston. It's a good idea to have a leak down test done, if you don't want to mess with buying one or making one yourself, take it to a reputable bike shop and ask them to do a leak down test for you. 8 pounds of air for a minimum of 10 minutes, should not drop any during that time. If it does, use some spray and liquid soap and locate the leak then repair.

Give us all the mods on your R, motor size, pipe being used, airbox mods, ported motor, size carb, type of air filter, stock or CR250 electronics, stock head, shaved head, stock head gasket, type of spark plug and gap size and most importantly your jet sizes in your carb, also your elevation where you ride, octane rating on fuel. Also, go buy a compression guage or borrow one and do a compression test. This is very important because it will give you a baseline going forward and also let you know if you need to run higher octane fuel like race gas or not.

There is absolutely nothing wrong with the Wiseco pistons for the R, thousands of people are using them with no problems, so quit worrying about that.

Regarding oil/fuel mixture, the old 20:1 mixture is outdated, especially with how today's synthetic and partial synthetic oils are manufactured. Just stick with a good synthetic or partial synthetic like Amsoil or any of the well known brands like BelRay, Motul, Maxima, etc., and mix at their recommendations. I personally use Amsoil, the S2000 synthetic which can be mixed at 50:1.

You're heat cycles sounded fine for the breakin, in fact you probably did more of a break in than 90% of people including myself!

Pull the cylinder and let us know what you found and get back to us with the information I've asked for and we'll go from there!

 

Thank you very much, I will pop the jug off as soon as I get the chance and even post some pics if I can. I did a compression test before it failed on me and it was up around 240lbs. I am guessing it was this high because Forward Motion Racing did a decking job in order to get the compression ratio up. Thank you guys for all the help, I will report back as soon as possible.
Brad

 

I actually heard that it is better to run a little extra oil during the break in......... not what was recommended on the bottle. I have seen alot of 2 strokes have engine jobs but they were all done with regular premix at 20:1, then switched to synthetic.

 

240?! I really hope you were using nothing less than C12! (108)