My Winter Project- Honda 250sx

[Lantz]

This spring I traded a 1986 xr200 for an 1985 250sx, it seems like its all there and it had spark. The guy I traded with said it smoked bad and had started to take it apart. I just got around to finish taking it apart yesterday and pulling the engine out. Next step will be to test compression and check the valves before I tear it down to see how bad it really is. I discovered that the right foot peg bracket was welded on, so I broke that off (it wasn't welded that great) and I cut off the homemade hitch that was welded on. My plan for this bike is to rebuild the engine and get it back together to use for trail riding within the next couple months.
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[tri again]

I had one smokin' like a *&^% and it turns out, the gas valve leaked gas into the oil and diluted it.
An oil change fixed the smoking.

Hope it's an easy simple fix.
You're in the right place for answers.
Search key is my fav and gets tons of posts all at once.
iF YOU DO TEAR IT DOWN, CHECK THE TIMING CHAIN AND GUIDES.
OOps, caps lock gets stuck....
EZ fix when they're apart.
and gear oil in the rear axle...and you'll have one of the best machines ever.

My favorite comment is:
":fix this and that and it will run Forever AGAIN".

[kebby28]

Is that a 200x front end?
I love the sx and cant wait to own one. Someday soon.

[hippie-89]

have fun i also have a project

[Lantz]

What do you mean by the gas valve? The guy I got it off of said it needed rings and the timing chain. He also said it had the front end off a 350x but im pretty sure its off a 200x. It also came with another set of painted gold handle bars? The headlight is also a single light housing.

[UPNATM]

Great llooking SX project. Pretty cool that the X front end was on it already.

[numbnutz]

Nice project!
I'm thinking about a complete tear down too.


nn

[408Fairmont]

Killer trike, I wold love an sx.

[Lantz]

Thanks for all the great comments. I went ahead and pulled the engine out since the engine mounting bolts and such were already removed from the trike. I figured I would be able to go through the engine this way. Also with the x front end I need to figure out some sort of steering stops, to keep the forks from hitting the gas tank. Any suggestions?

[UPNATM]

With the motor out, it's also the perfect time to clean up the frame, and other areas.
Flyingw has some pretty cool steering stops he made up himself. Shoot him a pm, or do a search. He posted them uup in a thread somewhere a while back.

[airbats801]

Is that a 200x front end?
I love the sx and cant wait to own one. Someday soon.

My only real complaint on them is they weigh a freaken ton. I own one, but still ride my 110 ironically.

[tri again]

What do you mean by the gas valve? The guy I got it off of said it needed rings and the timing chain. He also said it had the front end off a 350x but im pretty sure its off a 200x. It also came with another set of painted gold handle bars? The headlight is also a single light housing.

Gas tank petcock valve?
Of the 6 or 8 I have, none of them act normally. Most should be off at a dead horizontal but I have a few that want 4 or 10 o'clock position.
The 250 I was referring to had a leaky gas shut off valve and it leaked
a quart or so of gas into the oil and it smoked like a bbq since it was so diluted.

Now I check dipsticks for low AND high oil levels.
If the timing chain was slapping, the rings may also be ready.
EZ and fun with the engine out for sure.

[Lantz]

I tested the compression today and it was 95-100 psi. I couldn't really tell if the oil had gas in it or if it is just old oil. As far as the timing chain goes can I just put a new one in there and I'm good to go?

[Flyingw]

To get an accurate compression test, the engine needs to be at operating temp, choke off, throttle wide open. Doing it with a cold motor usually shows a low compression.

[Lantz]

I was looking over the engine and realized that the shifter was welded on, so after some careful cutting and some heat I managed to get it off. Hopefully I will be able to find a new shifter and be able to bolt it on. Any suggestions for shifters?
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[Flyingw]

Nope, the shift shaft is shot. You need a shift lever and shift shaft.

[Flyingw]

Here's a good one

http://www.ebay.com/itm/Honda-ATC-250SX-250-SX-ATV-OEM-Shift-Shaft-85-1985-681-/131072700669?pt=Motors_ATV_Parts_Accessories&hash=item1e848ab0fd&vxp=mtr

Shift lever

http://www.ebay.com/itm/Honda-ATC-250SX-250-SX-ATV-OEM-Shift-Lever-85-1985-670-/131050595745?pt=Motors_ATV_Parts_Accessories&hash=item1e833965a1&vxp=mtr

[Flyingw]

Here's another good one cheaper

http://www.ebay.com/itm/Honda-250-SX-250-ES-ATC-TRX-250-Fourtrax-Gear-Shaft-Spindle-/370966553547?&_trksid=p2056016.l4276

[Lantz]

To get an accurate compression test, the engine needs to be at operating temp, choke off, throttle wide open. Doing it with a cold motor usually shows a low compression.
Yea I figured it would be low since the engine wasn't hot. But I didn't have much option since the engine is out. I just wanted to get an idea for the compression, it didn't seem to bad for the engine being cold?

[Flyingw]

Another shift lever

http://www.ebay.com/itm/Honda-ATC250sx-ATC250es-Gear-Shift-Lever-OEM-Great-Shape-/151191273785?&_trksid=p2056016.l4276

[UPNATM]

The splines on your shift shaft look pretty boogered up. I would suggest trying to find a new one. It's been discontinued through Honda, but there is actually a pretty clean one on ebay right now. There are also a bunch of shift levers on ebay as well. If you don't want to go the eBay route you may also have some luck by posting an wtb add in the classifieds here.

Edit: lol, dang while I was typing Jim beat me to it.

Since you have to change the shift shaft it would also be a good time to check and or replace the shift pin if it happens to be broken, or become loose.

[Lantz]

I picked up a shift shaft on eBay along with a shift lever, and a gasket set. I got my carb back from Jim, it looks great by the way and I got the 350x lever on it. I'm goin to tear into the engine today, what should I be looking for when it comes to the shift pin?

[UPNATM]

I picked up a shift shaft on eBay along with a shift lever, and a gasket set.I'm goin to tear into the engine today, what should I be looking for when it comes to the shift pin?

Scroll down to the bottom of my page 2. I had to do mine a couple of months back. As you can see in the picture, mine was broken in half. Once you get the side cover off, and slide out the shaft, you should be able to see if its broken or not. I read up on a couple of threads, before I did the job, and found a post were Jim (FlyingW) said to lay the bike on its side, and that how I did it. It worked out great, and now shifts like a dream.
http://www.3wheelerworld.com/showthread.php/158333-A-few-pics-of-my-new-SX-and-build/page2

[Lantz]

A quick update, I have replaced the shift shaft, fixed the foot peg, fixed and bolted on a hitch, and put together a complete battery box that's now installed with a new battery. Jim (Flyingw) did an excellent job rebuilding my carb, it looks better than brand new. I tore down the engine while it was already out, the internals of the engine looked great.I went ahead and honed the cylinder, replaced the rings, and adjusted the valves. I have to finish putting the engine back together and get it back in the frame. Other things I have to do is get the steering stops set up, get the dash sorted out along with the rest of the wiring, and find a clamp for the air box.

[Lantz]

Can anyone recommend a good fuel filter? I found a couple on eBay, thoughts?

http://www.ebay.com/itm/140605766908?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

http://www.ebay.com/itm/300981639625?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

[UPNATM]

Can anyone recommend a good fuel filter? I found a couple on eBay, thoughts?

http://www.ebay.com/itm/140605766908?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

http://www.ebay.com/itm/300981639625?
_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

The top one is what I run on both of my sx's. Small, so it doesn't look goofy, and works good.
You can get them at any Napa, etc.

[Lantz]

Alright thanks I think I'll go with that one then. I've read good things about the sintered bronze filters but never used them.

[prairiedog14]

This is a nice project! I've been working on one myself.

[Lantz]

I just got back in from putting it all back together. The electric start doesn't work, but it starts when jumped. The kick starter doesn't return and just wants to spin. And it's leaking oil pretty good from the side gear case, it looks like someone tried to separate it by hammering it with a screwdriver.

[dougspcs]

Sounds like this thing has it's share of issues..

You're gonna dump a boat load into the engine alone.

Hope your really feeling it for this old girl!! From a dollars perspective it'll be cheaper to find another decent SX and use this one for parts!!

But if a rebuild is what you're looking to do then have at at it..there are a lot of talented guys in here. FlyingW for example has mad skillz..I've seen his work and bought his rebuilt carb numerous times.

Good guy to have in your corner as you start this project!

[Lantz]

The electric start doesn't worry me much its probably something simple, because it runs. I'm sure I can fix the kick start or live without it, once I get the electric start working.

Now, the side gear case is another story. Can I just pull that piece off, once the shaft is disconnected?

I'll post up some pics this evening.

[UPNATM]

The electric start doesn't worry me much its probably something simple, because it runs.

Check the switch. When I first got my SX running I had no electric start as well. After starting at the rear, and working my way all the way to the front I found it was just a bad connection on the switch. Took the switch apart, cleaned it up, and bam, started right up.

[Lantz]

Here's a picture of it all put back together.

[Lantz]

Well I got the oil leak all but fixed, insted of gushing oil it leaks a little when running and stops when parked. I got the electric start working (there was a red wire that wasn't hooked to the battery). I replaced the diff. cap today and the oil is more like brown sludge. How do I flush this out and what to replace it with, I would prefer something I can buy from an autoparts store. The kick starter is making a clicking noise. It doesn't return but still ratchets, and the kick starter wants to turn down when running. Is this something I should be worried about?

[Flyingw]

For right now, drain the diff and refill. Run it a little bit then drain it again and fill with Marvel Mystery oil and run it around for about 5-10 minutes at very slow speed or just jack the rear end up and let the motor turn the diff at idle for 5-10 minutes. Drain again and refill. Use 80/90w hypoid gear oil. Both oils are readily available at the auto parts store.

The kick starter is a whole different matter. The clutch cover has to come off. The book does not say how to install the kicker gear assy. There is a spring on the kicker, you have to hook the spring at the 6:00 position then you have to turn the kicker shaft CW to wind up the spring so the punch mark that is on the end of the licker shaft is past the 12:00 position then while holding the kicker assy, you have to drop the case side of the kicker in to the hole while meshing it with the idler gear then you can release the wound tension. Hard to describe but when the kicker is installed, the punch mark should be straight up at 12:00. I hate the SX kickers.

[Lantz]

Alright thanks, it seems like the shaft isn't disengaging. When running I can turn the kicker shaft back and it just turns back down.

On another note I cant get the 90* final gear drive to stop leaking oil. The 3 bolts were out when I got it, I read on here that those bolts shouldn't be removed?

[Flyingw]

Well you can take the bolts out but don't remove the side case gear assembly unless you are going to disassemble the tranny because the secondary shaft assembly is part of the tranny. The seal for the side case gear assembly is an oring. There is also a transfer boss tube with an oring on that. One of those two items is either defective or missing. It sounds like the entire engine needs to come apart.

[Lantz]

Thanks Jim for all your help, so it sounds like the engine has to come out to replace these o-rings? Other than these two problems (the oil leak, and the kick starter) its running great, It starts and runs good and all the gears are there.

This is where the oil was leaking out of the worst.

[Flyingw]

Ya, the tranny has to come apart to investigate the leak. No way around it.

[meatonastick]

I need to get myself a 250sx sometime, but around here even the hard-beaten ones are close to a thousand dollars, which is quite a bit more than i have haha. good luck on the project i hope it all comes together without too much trouble, but we all know how it goes.

[Lantz]

Well I pulled the right crankcase cover today. I discovered the thrust washer that sits on the back of the kicker shaft under the oil screen in the bottom of the crankcase. Is there any reason to remove the clutches as described in the manual? All the parts are there and in good shape. I'm thinking someone else disassembled the kicker shaft in the past and didn't tension the kicker spring?

[Lantz]

Well I got the kick starter all put back together, what a PIA. I was able to put it back together with out removing the clutches. Its still running great and no more clicking noise.

[Flyingw]

I agree, the ES/SX kickers are a huge pain to put back in.

[Lantz]

Yea, I sealed up the oil leak with some silicone. I wasn't about to tear it completely apart again. She doesn't leak a drop now. I also changed the oil in the rear and got the steering stop welded in. New brakes too, the rear brakes were shot. The front brakes still need some work, the caliper doesn't seem to be working right.

On another note we took a trip down to Hatfield and McCoy's about a week and a half ago. I rode the sx one of the days we were down there, and it ran great. The solenoid is only working about half the time but nothing that a piece of wire wont fix.

[lrharleyd77]

You will like the sx when you get it finished I have 3 of them and me and my buddies live them they will get you through about everything I have built about a dozen sx's so feel free to ask me a question if you run into a snag up I also have a few of these in parts