I have a 1996 dr125 with a bad engine. It started leaking oil bad. The bike doesn't have enough power for me being a bigger guy(245 lbs.). I like the how I sit on it it's comfy for me just not enough power can cruise at about 45-50 mph. I would love to put a 250 or bigger in it seeing that the engine is shot any way wondering where I could find a 250 engine to put in it and would they just so back in like it was a 125 or is there something that is different. What I could find out is that if i put in anything bigger than a 250 in i might as well buy a new bike. I'm hoping that isn't the case. Any help would be great. Thanks.