Honda 250SX Tranny ?

[kdagenais]

Hello,
Just wondering if anyone with a 250SX has had a 3rd gear slippage problem before and if so what the problem was. I have tore the engine down on my Uncles trike cause third gear was slipping really bad. All the gears in the tranny appear to be in good shape. The only thing I noticed that looked wore was the spline on the output shaft. But I would think if that was the problem it would've slipped in all gears not just third. Has anyone ever encountered this problem and your thoughs are welcome.

[Howdy]

Never really had this problem to deal with. But if it helps I have a good 250sx and a couple 250es tranny's available.
Howdy

[bigredhead]

Mine will clickyclack between 3rd to 2nd once in a while.. and 2nd to 3rd etc.. never totally figured it out.. after enough hours riding, i've learned how to shift and avoid this happening.. but i need to get in there at some point..

Does it only do this when you shift .. ?

Once in gear does it slip on it's own ?

[kdagenais]

Never really had this problem to deal with. But if it helps I have a good 250sx and a couple 250es tranny's available.
Howdy
Howdy sent you a PM!

[Dirtcrasher]

I find the SX to have bad spots in the shift drum, maybe from popping out of gear because its an auto and sometimes people forget to downshift.

[Howdy]

Howdy sent you a PM!

Got it! Waiting on a call back from my friend.
Howdy

[pomona51]

How much would it cost to rebuild a 250sx tranny and motor.

[kdagenais]

How much would it cost to rebuild a 250sx tranny and motor.
It really depends on what you are replacing and where you are getting the parts from. If you are buying all new stuff it can get expensive quick. Then if you go used depending on how patient you are you can save allot.

[pomona51]

Thanks kdagenais, its always nice to know how much you could spend.

[Dirtcrasher]

How much would it cost to rebuild a 250sx tranny and motor.


As for the tranny - you won't ever have to rebuild an SX tranny. You may have to "fix" it. I find the SX auto tranny indestructable and the gears are as beefy as any 350X gear - I guarantee that. The SX tranny failures seem to result from abuse such as holding the shift lever up to "clutch it" and then dumping it while gassing it. Another problem is people taking off in to high of a gear because they don't understand how an auto tranny works, this causes the SX tranny to jump out of gear and even one time that this happens, the wear begins. The shift drum seems to be a weak link, I'm not sure is the mechanism that holds the SX in gear is to blame but the drum is what suffers. I've seen a few bad grooves in the drum and the journal on the shift fork that rides in that groove gets ruined also. Then you begin to have problems. The other problem I've seen a few people do is the removal of the final drive output. It slides right out with just a few allen bolts and allows motor removal or drive shaft and rubber boot repairs. BUT, it also allows one teenie tiny thrust washer to get lost in the tranny during removal. The drive slides back in but soon first gear begins to pop out and later the real damage begins. Funny though, that washer floating around in the tranny never seems to jam up but rather the lack of it in it's proper place seems to start the damage.
As along as the oil is kept full then the SX tranny bearings will last forever and the only other problems are the one way clutches which if you change your oil and keep it full, they will last a lifetime also - IMO.
While on the oil subject and your motor rebuild question, a standard top end rebild can range quite a bit. If the oil doesn't get low then the cam and it's jopurnals in the head will be fine. Then simply a piston and ring and sometimes not even a bore job will keep the SX running smooth. But a lack of oil just like in the ever so desired "good journal" 350X head, will require a good replacement head. Piston kit is about 75$, valves are about 50$ for the pair with another 50$ to clean up the head and new valve seals etc. Ruin the cam and get an EBAY cam for 20$ or a Web cam for 150$. In time the cam chain does seem to stretch beyond the self adjuster and I think that puppy is about 70$ from Honda.
To me, I guess it all boils down to oil and abuse. The SX is a great motor and easy to keep running smooth. Most used tranny and motor parts can fix your problem and are cheap on EBAY. I did a performance top end on my 85 motor sparing no cost and it was about 500$ to rebuild, thats a high comp piston, new valves, bore, web cam, cam chain and other misc parts. I didn't even touch the lower end which is still stock.

[kdagenais]

As for the tranny - you won't ever have to rebuild an SX tranny. You may have to "fix" it. I find the SX auto tranny indestructable and the gears are as beefy as any 350X gear - I guarantee that. The SX tranny failures seem to result from abuse such as holding the shift lever up to "clutch it" and then dumping it while gassing it. Another problem is people taking off in to high of a gear because they don't understand how an auto tranny works, this causes the SX tranny to jump out of gear and even one time that this happens, the wear begins. The shift drum seems to be a weak link, I'm not sure is the mechanism that holds the SX in gear is to blame but the drum is what suffers. I've seen a few bad grooves in the drum and the journal on the shift fork that rides in that groove gets ruined also. Then you begin to have problems. The other problem I've seen a few people do is the removal of the final drive output. It slides right out with just a few allen bolts and allows motor removal or drive shaft and rubber boot repairs. BUT, it also allows one teenie tiny thrust washer to get lost in the tranny during removal. The drive slides back in but soon first gear begins to pop out and later the real damage begins. Funny though, that washer floating around in the tranny never seems to jam up but rather the lack of it in it's proper place seems to start the damage.
As along as the oil is kept full then the SX tranny bearings will last forever and the only other problems are the one way clutches which if you change your oil and keep it full, they will last a lifetime also - IMO.
While on the oil subject and your motor rebuild question, a standard top end rebild can range quite a bit. If the oil doesn't get low then the cam and it's jopurnals in the head will be fine. Then simply a piston and ring and sometimes not even a bore job will keep the SX running smooth. But a lack of oil just like in the ever so desired "good journal" 350X head, will require a good replacement head. Piston kit is about 75$, valves are about 50$ for the pair with another 50$ to clean up the head and new valve seals etc. Ruin the cam and get an EBAY cam for 20$ or a Web cam for 150$. In time the cam chain does seem to stretch beyond the self adjuster and I think that puppy is about 70$ from Honda.
To me, I guess it all boils down to oil and abuse. The SX is a great motor and easy to keep running smooth. Most used tranny and motor parts can fix your problem and are cheap on EBAY. I did a performance top end on my 85 motor sparing no cost and it was about 500$ to rebuild, thats a high comp piston, new valves, bore, web cam, cam chain and other misc parts. I didn't even touch the lower end which is still stock.

My Uncle really rides this thing hard and everytime I see it makes me want to cry. But I will give it this though he has had this bike since new and this is the first tranny trouble ever. He has always ridden this trike the same if not harder when it was new.