honda 250r questions

[yamaha driver]

well my 250r finnaly needs to be rebuilt was not running right yesterday real bogged down kinda sad i guess lol made sure its gettin fuel and stuff then checked compression it was at 100psi :cry: so i tore it apart today finding out it blew up once before the head was full of little indents/ gouges and the piston was just wore down real bad. so sent it out to my trusted machine shop to get a new piston/ bored and fix the head so im going 1mm over he is going to grind down the head and also he said its going to have more compression since he is doing that. so my questions are since i never rebuilt a 250r before how should i start out the new rebuild... what mixture and how to "break it in" since this is costing like 400 bucks i dont want to mess it up. thanks everybody

[Dirtcrasher]

Grinding/cutting the head lessens the compression so I'm not sure what he meant.

Porting it may require larger juts but cleaning up a crappy head won't..........

Ya just just break them all in the same way. Easy on the throttle for a bit, cool it off. A bit more throttle blips of 3/4 throttle and cool it off. Then run it but don't go nuts for a few times, change the tranny oil and then beat the snot out of it............

[yamaha driver]

well he said he is grinding down the inside and also shaving it down?? forgot to say that and should i drive it around like at 1/4 throttle and 3/4 like you are saying or just in neutral and how long of periods

[Dirtcrasher]

If he shaves it, the dome will have more compression; He is probably cleaning up the dome then shaving the gasket surface........

[ceaserthethird]

Watch out for the compression, If it's High you'll need to Run Race Gas!

[yamaha driver]

na not going that high is a standard comp piston just had to fix head. and also how long should i drive it when breaking it in. i rebuilt oil injection 4 wheelers before and i knew you had to mix oil in the gas on a rebuild so on a 250r do u have to mix it stronger?? and if so what ratio. And thanks for the info

[Gripit'n'ripit]

I've kept the fuel/oil ratio the same when i break mine in. I generally run it for ~5 minutes, enough to heat it up, then let it cool. Then run it for progressively longer times.

[yamaha driver]

ok cool thanks alot and should you drive it around going threw the gears but at low rpms or keep it in first and just kinda putt around