300sx questions

[beastybaconman]

I'm planing on trading my 86 rm 250 for a 85 250sx this weekend. The guy selling the sx says it has the head, cam, and piston from a 300ex, a full cobra exhaust, barnett clutch, and a 350x front end. The guy owns a small engine repair shop so I figure it should be a decent running rig. I was just wondering if anyone else has tried the 300 top end conversion and does it really make much of a difference?

[jakep53]

ohh look at the bike in the background it's one of them 2wd rokon's very cool!!

[beastybaconman]

Just picked it up and took her for a spin. She's not perfect but she loves life. The 350x front end is a little weird cause it sits up so high, I can pick up the front end in every gear real easy, and it keeps up with my neighbor's crf 230 no problem. I took a look at the identification tag thing on the front and it says 1/85 on it does that mean it's the first one made in 85 or something? Also there is some fluid leaking out of the top of the forks, anyone know what could be causing this?

[jakep53]

1/85 is the first month of 85

[beastybaconman]

Ok thanks, I figured it was something like that

[jb2wheels]

... Also there is some fluid leaking out of the top of the forks, anyone know what could be causing this?

The bashed schrader valve on the fork cap.

[beastybaconman]

I thought it looked a little rough, I just wanted to make sure it wasnt something else, are those valves pretty easy to replace?

[redsox]

your forks look a bit bent. also, i'm no 350x expert, but i think its supposed to be a leading front axel. i think. not sure. i think your forks are backwards. your wheelbase is weird... any help from someone that knows??

[beastybaconman]

Thanks for mentioning that I looked at some pictures of 350x's and it looks like my forks are on backwards. Thats probably why it's so easy to wheelie

[beastybaconman]

Just turned the forks around rides a lot better, they are bent a little is there any easy way to straighten them up or am I better off just getting new ones?

[Xfile]

Just turned the forks around rides a lot better, they are bent a little is there any easy way to straighten them up or am I better off just getting new ones?

Bring them to a machine shop with a good press...a shop in my area straightens them for $30 a pair.

[beastybaconman]

Alright I'll try one of the machine shops around here, thanks for the reply

[beastybaconman]

I was just messing with my front wheel to get it centered more and I found that the axle bolt has different threads than the threads on the fork. Because of this, where it threads into the fork it's a little beat up. From what I can tell it is the front wheel from a 350x so I don't know why it isn't fitting, anyone know what could be going on? Maybe the previous owners used an axle bolt off a different rig or something?

[YTZ drew]

Just to let you know, a 300ex top end is identical to a 250x top end, except it has 282cc cast into it instead. The 300 gets it extra cc's from the stroke. I actually didn't realize that 300ex tops fit onto 250 Sx cases, but if that's what you have, I think you're still only at 250cc.

[beastybaconman]

I don't know if it is the whole top end off the 300, the way the guy was talking it was just the head and cam but not the cylinder. And if it did have the cylinder off the 300 with the longer stroke wouldn't that make it have less power?