Honda 250sx performance mods

[edge]

I just got a 85 250sx and need to know where to start with mods. It is stock except for the air filter. What mods are the best bang for the buck? I saw a post that mentioned a cobra pipe.

[86waterpumper]

Hey, ask bbechtel16 how he likes his 10 to 1 compression piston that he got for his. I assume he got it from powroll. They had them on sale awhile back for 25 bucks! If your bike already is smoking a bit or needs rebuilt might consider that.

http://www.powroll.com/honda_garage_sale.htm

[bbechtel16]

Yeah that piston, 10.5:1, 2mm overbore (260cc), it rules. I can do much better wheelies in 3rd now.

Also get yourself a 200X, 350X, or 250R front end (forks, triple tree, brakes, wheel/tire, lights and fender optional). I have a 350X front end (lights not going yet but I'm working on it and shall report and post new pics/avatar) and 250SXracer recently got a 200X front for his SX (for now all he has is the forks, triple tree, and wheel/tire). Since he doesn't have the whole machine going yet I dunno how it rides, but sitting on it has a nice stance. Als250 has a 200X front also I think.

Go for a cam if you got the bucks. I'd like to get one eventually. www.webcamshafts.com

350X carb: Once you have the exhaust, piston, cams, and intake mods, I believe it would definitely benefit to have a bigger carb to get more air/fuel into the engine. I don't have any intake or cams, but I'm still considering this because I need a 40 dollar part for my carb to make the choke work and for that I could get a 350X carb with a choke level built in style.

Rear Shock upgrade: We of the board haven't really reached a conclusion on this yet, but the desire is there. We'll keep you posted.

You may want to consider smaller rear tires (lower profile 18 or 20 inch) if you doing tight woods riding (no mudding though) or something where a lower final gear ratio would be desirable. It will corner better due to a lowered center of gravity and you will be able to kick the back end out easier due to less traction. I have decided to stick with 22s though because I don't want to lose my top speed and traction. It all depends on you for this one, where you ride, what you want, and your style.

Wheel spacers: These will increase your rear width which will allow you to corner better and not roll as easily. I don't have them, yet, you will want to talk to als250 about these also.

Wheels: If your rear wheels look pretty beat and you want to play dress up, you could get yourself some shiny new aluminum wheels for looks and weight reduction (though not the most cost effective upgrade).

edit: Forgot to say stuff about exhaust. I guess the Cobra is the only custom fit, full exhuast avalible now. 250sxracer has one, I like them, very loud though. If you don't mind the noise and neither do your neighbors, go for it. The only other down side of the cobra is the paint, its just simply sucks. All of the paint WILL fall off your headpipe. So then sandblast the headpipe, and get some decent paint on it. I have a White Brothers e-series universal rigged style on mine, its a little quieter, and is adjustible. But i'm probably losing performance though the plumping (litterally)and stock headpipe (cobra's is "oversized").

[ATC crazy]

Why couldn't you have started this thred when I still had my SX :?: :x

I wish I never sold my baby :( :( :(

[bbechtel16]

How's that work for you edge? Any questions?

[edge]

yea, a couple....

What is the reason behind swapping out the front end?

What is the best performing intake?

How difficult is the cam swap?

[kilabeez0]

u have all those ATV's and u dont know how to swap a cam? :oops:

[edge]

hey....I know where the oil goes into the carburator..... :D :D

[kilabeez0]

hey powroll and webcams have pretty much the same grinds, but webcams are half the price. anyone have any experience with these 2? and will powroll do the work for you if u send them your engine?

[87 250SX]

Awwww ATC Crazy!!! Now i own your baby LOL runs good to

[MR ATC]

first let me say webcams arte cheaper because they are junk...try megacycle much better product that will actually last.

second "we of the board" have found a solution to the rear shock problem its called works performance give them a call.

third the 250sx was not designed to be a hop up model. by the time you spend all that money on performance parts along with the sx you could have bought a 350X that will much better even if box stock and worn out.

fourth the reason for the 200X,350X,250R, front end is better suspension with the forks and better handling with the narrower front tire

[ATC crazy]

Awwww ATC Crazy!!! Now i own your baby LOL runs good to

Purrin' like a kitten huh? ;)

[kilabeez0]

while we're on this topic...why are webcams junk? And are megacycle better than powroll cams? And should I spend the money upgrading everything on my 200x or will I not be satisfied at the end...and i mean upgrading everything....bored, cams, clutch, suspension.

I just split the case on my junk bottom end for the learning experience...piece of cake. I have a stock piston on the way and will be getting my cylinder honed, and the head cleaned with a valve job. After I put it all back together I'm going to ride for the season, and then I'll consider going all out next winter if it's worth it.

[MR ATC]

while we're on this topic...why are webcams junk? And are megacycle better than powroll cams? And should I spend the money upgrading everything on my 200x or will I not be satisfied at the end...and i mean upgrading everything....bored, cams, clutch, suspension.

I just split the case on my junk bottom end for the learning experience...piece of cake. I have a stock piston on the way and will be getting my cylinder honed, and the head cleaned with a valve job. After I put it all back together I'm going to ride for the season, and then I'll consider going all out next winter if it's worth it.

web cams are junk because they are just rewelds. they take a old worn cam weld globs of metal on them and remachine them to whatever duration and lift they want. weld will eventually wear off

megacycle cams are billet cam's made from new stock and will last a lot longer.

then with web cam you have to send in your old cam as a core exchange and there cam cost about 100.00 megacycle you keep your own cam and the new cam only cost 140.00 to me to be able to have my old cam and a new higher quality cam for only 40.00 more is a sound investment.

powroll cams are also rewelds but they are a little better quality.

as far as modifying your 200X i do not recomend it since most modified 200X's don't last very long the motor is too stressed when again a poor running 350X will still be worlds ahead of a modified 200x of 250sx. then you have the meager suspension that even modified wont be comparable to the 350X

if your thinking of modifying these machines for more power and or suspension just step up to the big leagues. 350X or 250R

[slippy4]

what would you recommend for just better overall power on a stock 200x? (cam that is)

[MR ATC]

megacycle makes a all around cam that will improve your power through out the rpm range yet not require H.D. valve springs which is another thing to consider when getting a cam most cams require them (h.d. valve springs)

[slippy4]

is there a website for megacycle?

[MR ATC]

no not that i know of you should be able to get there # from a Honda or other dealership if not pm me and i'll look it up for you (all my stuff is packed away)

[kilabeez0]

I wonder if I should spend the hundreds to have the frame and such powdercoated? Or if I should do like i did my 110 and rattle can it, still replace all the plastic and seat cover, and make it look nice on a budget, because now that you said it, i'll probably want to go to a 350 or 250r. What are your opinions on that?

[250SX_rider]

I also have a stock 250SX...its a '85... I have 2 questions :

Is it a lot faster with a K&N air filter ?

Is there some modifications I can do without buying some parts? (like to polish things, and so on...)

Thx

[ATC crazy]

You will notice a small increase in power with a K&N air filter...but it won't make you win every race...

[bbechtel16]

I also have a stock 250SX...its a '85... I have 2 questions :

Is it a lot faster with a K&N air filter ?

Is there some modifications I can do without buying some parts? (like to polish things, and so on...)

Thx

Couldn't tell you about the filter, I'm still stock (embarassed). You might want to try to make a vented airbox maybe. Umm.... thats all the freebies that are comming to my mind right now.

UPDATE: I got my 350X lights on tonight, they rock! I did a nice clean install too (at least on the headlight end of things, the battery end is messy). I shall post pics of the trike (new avatar), pics of the mods upclose, and some instructions on how do it. I also plan to stir conversation about a driving lights (high and low both on when you turn on high) mod I'm considering but I didn't go ahead and do it because of fear of overheating the bulbs. Although I found I can get the effect by holding the switch in just the right position.

[Green Monster]

Anyone got the part# for the K&N filter for our 250SX and where to get one? :shock:

I want to do the K&N filter and Cobra pipe in the near furture. :-D

[bbechtel16]

Anyone got the part# for the K&N filter for our 250SX and where to get one? :shock:

I want to do the K&N filter and Cobra pipe in the near furture. :-D

Don't know the part number but I would guess that eBay would be the best place to buy it. I think they have pretty decent avalibility and great prices.

[250SX_rider]

I just found the # of the air filter at a cycleshop, so look at there:

http://www.motorcycleproshop.com/acc/k&n/honda.asp

For the cobra pipe:

http://www.atvpartsdepot.com/noname2.html

Oh and yesterday i started to modify my battery holder, cuz i'm gonna put a bigger one in it :)

Cya all

[250SX_rider]

Does a air filter of a 200X also work on a 250SX ??
If so, just bid for it right there:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=43979&item=2427815842

:twisted:

[Green Monster]

Thanks guys!!!!!!! :-D

[bbechtel16]

I just found the # of the air filter at a cycleshop, so look at there:

http://www.motorcycleproshop.com/acc/k&n/honda.asp

For the cobra pipe:

http://www.atvpartsdepot.com/noname2.html

Oh and yesterday i started to modify my battery holder, cuz i'm gonna put a bigger one in it :)

Cya all

May I ask why you would want to put a bigger battery in the SX?

[250SX_rider]

my old one wasn't working anymore, but now my dad found a stock one, so I won't have to modify the battery holder...

oh and i have a question for u guys.
My battery is not reloading good!
I did a multimeter test on the battery, and when my SX wasn't running, it was 12,54V, i started the engine, it was now 12,48V and when i was giving a lil throttle to it, it was 12,52V....on my dad's Fourtrax it climbed to 14V when he gave it some throttle... :?
I changed the left-side cover (with the part on it, of course), and it wasn't working anymore...help me !!!

[bbechtel16]

my old one wasn't working anymore, but now my dad found a stock one, so I won't have to modify the battery holder...

oh and i have a question for u guys.
My battery is not reloading good!
I did a multimeter test on the battery, and when my SX wasn't running, it was 12,54V, i started the engine, it was now 12,48V and when i was giving a lil throttle to it, it was 12,52V....on my dad's Fourtrax it climbed to 14V when he gave it some throttle... :?
I changed the left-side cover (with the part on it, of course), and it wasn't working anymore...help me !!!

I guess your alternator died?

[250SX_rider]

I changed the stator on it...

[bbechtel16]

I changed the stator on it...

Oh right. I dunno. (eletrical idoit) :oops:

[250SX_rider]

Guys did u know that u could put a big bore kit in a 250SX that bumps displacement from 246cc to approximately 300cc ?? That's what i read in this website :

http://users.nlamerica.com/dixiebai/atv/html/sx1.html

It's a complete restoration of a 1985 250SX :o
And read it well, u'll see...
And after it's 300cc, u could put a 2mm oversize piston, a pipe and a K&N air filter, u would have an awesome trike :-P

Cya

[bbechtel16]

Guys did u know that u could put a big bore kit in a 250SX that bumps displacement from 246cc to approximately 300cc ?? That's what i read in this website :

http://users.nlamerica.com/dixiebai/atv/html/sx1.html

It's a complete restoration of a 1985 250SX :o
And read it well, u'll see...
And after it's 300cc, u could put a 2mm oversize piston, a pipe and a K&N air filter, u would have an awesome trike :-P

Cya

Thanks for the link. For some reason it looked firmilar; but I don't remember them mentioning the big bore kit. Sorry to burst your bubble though, you couldn't run a 2mm overbore piston like mine with that big bore kit because it appears they get the 300cc from all bore. The point is, I want that kit! Well maybe, if its stock compression hhmm, I dunno. Anyone know where these things are still avalible?

[3WheelsForever]

I found that link when I still had my SX. I had no luck what so ever in getting the 300cc big bore kit. I tried emailing the company and the makers of the site at least five times. Not once did I get a reply so I gave up. I would enjoy having that kit also. It would be awesome!!!!! :twisted:

[peco250sx]

"third the 250sx was not designed to be a hop up model. by the time you spend all that money on performance parts along with the sx you could have bought a 350X that will much better even if box stock and worn out."

ya but then you wouldnt have auto clutch, reverse, shaft drive and super low first gear

[The Goat]

you just dug up a three year old thread to make a smart remark to mr atc....

lol...YOU SIR ARE A GOD!

don't have a super low first huh? tell ya what, let's hook a 350x to a 250x and see who drags who around the yard.

[SCRAMCHARGER318]

you just dug up a three year old thread to make a smart remark to mr atc....

lol...YOU SIR ARE A GOD!

don't have a super low first huh? tell ya what, let's hook a 350x to a 250x and see who drags who around the yard.

that's a easy one the sx would probably win, it's heavier and lower than the 350x, the 350x would either spin or you would stand it up on the grab bar. these are both big torque machines but the sx would simply have more traction due to dead weight especially on the rear wheels

[peco250sx]

thats not how i wanted it to come across so ill re-phrase what i said, the reason somepeople might not want to change over to a 350x is that some of the 250sx features are very useful in tight quarters or hauling. sorry if i came across as a smartass

p.s. i didnt know this was an old thread i just searched it up

[oscarmayer]

we are trying to get a group buy in some weisco pistons for the 250 sx/es series motor. there's a thread about it.

[The Goat]

the piston isn't still available...since when?

[oscarmayer]

called weisco friday. they said they do not have them. they have the 4v but not the 2v that the SX and ES use. :(