First, sorry my english.

I have a Sportsman XP 850 H.O. ESP my 2014
I modified the engine and now I have about 90 horsepower in engine.

I have one problem. Belt slips.

I used High Lifter 3GX (HLP211) belt. First one product day was 02/2014. That was very good and it not slided. But it broke down.

I bought new one, but it sliding. New belt product day is 08/2014. Same product number, same package ect. The rubber material is different, it´s harder.

Can You help me? That is better belt? That belt You use?

Thanks,
Jukka