1985 250sx bore

[bebeav]

can i oversize my 250sx cylinder? if yes, will it be safe or will i have some prog with my engine after? do they make a oversize cc kit for the 250sx engine?


ALP
Beav

[bebeav]

i just see that the 250sx piston is the same as the trx250x.

is there any possible mod for this quad?

like big bore kit or something like that?

will a 300ex head will fit on a trx250x or on a 250sx?

will a trx250x carb(36mm) will fit on a 250sx. (oroiginal carb 27mm)?
if yes will it improve performance?

ALP
Beav

[bebeav]

anyone?

ALP
Beav

[BigRedRunner]

The '85-'87 SX/ES/Fourtrax all share the same engine. I can get you a .25, .50, .75 and 1.00 oversizes if you want. Rings would be around $26, piston $48, pin $9.50, clips $.50 (for both), and the top end gasket set for $30. All genuine OEM honda stuff still in the box. If your dealer is half way decent, you should come close to those prices. If they're the typical jerks and charge full list price, then these prices should be alot better for you then.

[bebeav]

i found a dealer that can oversizes it for 50$ (can). i think i'll do a 2mm oversized if it's possible cause i can buy the piston from honda garage sale. thx anyway

is somone know why on the trx250x there is a 36mm carb and a 27 mm card on the 250sx???

ALP
Beav

[Dirtcrasher]

If they're the same engine I sure would like to know why myself!!

[BigRedRunner]

I don't know about the X designation. I've only seen the ones I'm talking about as just foutrax250. I'm talking about 250cc shaft drive, reverse, electric start, units from '85-'87. The only real difference bewteen the three is that the SX has a little sportier gearing and is black.

[bebeav]

euh....i would like to see your black 250sx cause i never seen one and if they exist i need to know cause it's what i want to do ( paint all my fender black or try to find some black fenders for my sx).


ALP
Beav

[BigRedRunner]

Lol, I should have clarified. The engine and gearbox are black, the trike is red and towards the last, white. I'm all into this because I've got a ba$tard motor in my ES. Fourtrax bottom end, ES top half, with an SX piston. :D I had a complete fourtrax eninge/gearbox in there, but it was smoking bad. It looks to have gotten hot. The motor that came with the ES had a broken crank. So years later I used he good fourtrax bottom, low hours original ES top end and an SX piston. I used the SX piston because my old one was stuck to the bore and she got a little dented dislodging it . They like to do that after sitting seven years. :rolleyes:

[GlennMc]

bebeav;

If you are going to oversize your cylinder, do the minimum oversize that is required to clean up and refresh your engine. If you do go to a 2mm oversize piston, you would remove any chance of ever reboring the cylinder again. A proper "big-bore" job from Powroll or similar companies either installs a larger sleeve in a standard cylinder or provides an aftermarket cylinder. Good Luck. GlennMc.

[TimSr]

I agree with GlennMc 100%. A bore job is NOT a performance modification, which is what I get the impression you are looking for here. A bore job is to clean up irregularities in worn into the cyclinder that causes reduced compression, and you should always go the minimim necessary, or next time its necessary itll cost you big bucks.

[bbechtel16]

While we're on the subject, what displacement difference does that 2mm overbore kit make in the 250SX?

[bbechtel16]

bumpity bump

[3WheelHouston]

Like it or not, a bore job does improve performance. Check out Powroll.com, their big bore kits were on sale for 25.00, regular 140 last time I checked. I say anything that makes your trike perform better is a performance mod. And that includes boring. Like the adage says, no replacement for displacement