SX ES non-motor diffences?

[TheRealFatShady]

I am looking at a 250SX, 1987. I am going to use a TRX300 big bore engine with a torque-based cam and gear reduction.

Not using a 250es/sx engine, so those differences are not important.

I noticed the fenders/seats are different. Is the SX suspension better? Even though I am going for torque, I may want the 'sporty' SX as I believe the rear ends may be the same???

I can sell my 'naked' beat BR for $300 and found an 87 SX for $500, but has a burn hole in rear fender. Will cost me more than $500 for side covers, rear fenders, trunk lid, front fender, tank for my BR, so for $200 I may get nicerl suspension, spare running 250 engine.

Worth it? And any difference I overlooked? SX forks are slightly longer, may have missed that.

[MudBug]

besides engines, everythings different hahaha.

[TheRealFatShady]

Are the rear ends the same? Or is there some gearing in the rear that wouldn't work too well for a full on swamp bike like Skiffy and Mondexbrute made?

Found another SX for $400/obo needs motor work. I can sell my BR for $300 (looks like , no plastics and un-usable tank,missing parts) so $100 can buy me a 'potentially' cleaner frame, good plastics, tank, etc. Waiting on pics.

[MudBug]

The swing arms are different. The ES mounts inside the frame, and the SX outside. I heard that the rear end gearing is higher on the SX but I have seen no proof.

[TheRealFatShady]

Do you think it to be wise to swap the rear end and keep the one from the BR if I plan on torque? I would really like to confirm today so I can buy it. $100 or less in theory gets me a nicer looking bike, hell a tank would run me that just about!

I'm tempted to get a strong 376cc machine, but I have a 350x and ATC480R, so I want to remain true to this and get a torque based monster.

[Woodsrider]

Yeah...there is supposed to be a one tooth difference in the ring and pinion gears between the ES and SX...but they are interchangeable. Like MudBug said, they are different machines. The transmissions are geared slightly differently. They have different swingarms, but hubs for the same years match between the SX and ES('85's have the same hubs...'86 and '87 hubs are the same). Some of the control cables are the same. Air filters are different. Frames are different. I believe foot pegs/rear brake pedal assemblies are the same. Brake parts match for same years.Wiring harnesses are not the same(lengthwise) either. Lots of parts match....but lots don't.

[TheRealFatShady]

Thanks.

http://www.3wheelerworld.com/showthr...e-in-the-gears

Saw it there too. I guess I can swap the rears and just not the swingarm, hopefully it's not too much work. Would like to sell my BR Monday morning, so I'm hoping I can do before then.

Once I have a BR rear on it, I will have the same gearing as a BR, correct? (using a BR engine, then a TRX300 big bore engine)

[Woodsrider]

I think that the difference in the rear end was because of the difference in tire size of each machine. I can only give my opinion on what I THINK you may be wanting to do. If you are "powering up" with a bigger engine, I wouldn't worry about it. On the other hand, if you plan on using monster tires and the mud is extreme, every little bit will help to make it a better machine for that purpose.

[Woodsrider]

Once I have a BR rear on it, I will have the same gearing as a BR, correct? (using a BR engine, then a TRX300 big bore engine)

Well...the tires are part of the gearing too, so BR engine+ BR rear end+ SX tires = geared lower than a BR. As for the TRX300 gearing, I have no idea how that compares to a BR, but they are pretty slow machines, so I would guess that they are geared similarly to a BR.

[TheRealFatShady]

Yep, going to use the BR rear end, both that and the SX are better made than the TRX300's.

Then a TRX300, 459 (torque) cam, 376cc Thumper big bore kit, 300ex gear reduction (lowers gearing, I believe by 14-18% overall?) and that should be good to spin 30's. I know Skiffy did it, on youtube. His engine and rear end are fine. Mine will have a bigger engine (his is a really souped up BR engine) and lower gearing from the gear reduction. So in theory, it should work no problem

EDIT: I believe I read the BR gear reduction in a TRX300 is about a 4% reduction, so most people just use the 300ex as its much more of a difference.

I don't know how the 30" tires will affect top speed, but to me, this is a mud monster. Will go through piles of snow, and plow. And tow anything. I have other trikes for speed, so this is just a monster in the swamp, and that's fine with me.

[dajeepman]

Yep, going to use the BR rear end, both that and the SX are better made than the TRX300's.

Then a TRX300, 459 (torque) cam, 376cc Thumper big bore kit, 300ex gear reduction (lowers gearing, I believe by 14-18% overall?) and that should be good to spin 30's. I know Skiffy did it, on youtube. His engine and rear end are fine. Mine will have a bigger engine (his is a really souped up BR engine) and lower gearing from the gear reduction. So in theory, it should work no problem

EDIT: I believe I read the BR gear reduction in a TRX300 is about a 4% reduction, so most people just use the 300ex as its much more of a difference.

I don't know how the 30" tires will affect top speed, but to me, this is a mud monster. Will go through piles of snow, and plow. And tow anything. I have other trikes for speed, so this is just a monster in the swamp, and that's fine with me.

cant wait till you start this swap.. hope you do a write up on it and take plenty of pictures lol

[TheRealFatShady]

Still debating, it appears that the SX doesn't have racks/hitch/trunk. That may prevent me from doing it. But I suppose I can always sell the SX stock if I find a BR that has all plastics for a good price.

Most work will be in the TRX engine, tires, the only 'special' part to the frame will be the lift/shock mount, and fork extension. I am gunna buy a spare rear end so I don't have that problem if I lift it then plan to sell the SX and keep the 'hopped up' engine.

[MudBug]

The racks were optional for the SX. Most I have seen have them.