I would do a compression test and at the next rebuild check for piston slap and check the rod bearing. I use Honda hp2 synthetic mixed at 20:1 sounds kinda thick but my bike pulls hard and dosen't foul plugs and a lil rich to me is better than a lil lean.

 

I watched your video...250r's have that rattle. I've been around 'em for a long time and they all make that noise. Sounded fine to me, seems like it runs good!

 

how fast are these 250rs?
just wondering
and size wise how big compared to others?
like a 250ex?

 

about as big as a 400ex. Thay have a good power to weight ratio. Twice the power of a 250c.c. 4 stroke with about half the weight. It's not really how fast it is, just how fast it gets there, and it gets there quick.

 

Yeah, it's definitely fast.

I'm still trying to sell it. No luck so far. I just put it at $1300 and hoping to have it sold soon.