250ES/ 250SX experts please stop in!

[hatc200x1]

I am having a pickle of a time on my 86 es. I finally got it all together and riding. But guess what, the engine has transmission/clutch issues. When you accelerate hard, it will sometimes not have power to the rear wheels, you can feel/hear something not catching. It will do it in 1st quite easily and 2nd a little bit. It is not the differential, I just swapped the whole rear end with one of my 85's and it does the same thing. PLEASE HELP!

[dougspcs]

Sounds like your clutches are smoked..there is a ton of reference threads in here on clutch operation and replacement.

[hatc200x1]

I'm not to sure it would be the clutch. There is a very distinct sound of gears skipping. It will only do it in gears with a lot of torque like 1st and 2nd. In my mind it cannot be the clutch because in 3rd 4th and 5th I can lug it way down and pin it and it will not skip gears.

[the great gazoo]

Oh shite, sounds like shift forks.I had a similar issue, no third gear. Split the cases & replaced 2 shift forks.
The bike ran great for two-three years & it started making the noise you're describing, & then third just totally gave out. the only other thing is the shift drum, but I'm no transmission expert. good luck & keep posting up, TGG

[hatc200x1]

I had a friend told me it could possibly be the output shaft assembly on the engine. It is an 85 trx250 engine if that helps. It shifts fine and everything, but just skips.

[Thorpe]

I would pull the left case and see if pin #21 is still intact... It causes all sorts of weird tranny/shifting issues... (At least did on my ES when it broke)

[Chopsaw]

Just gonna throw this in , did you install the spring between the drive shaft and the pinion gear when you changed the differential ?

[Keepah Rolln]

What kind of oil you running in it?

[hatc200x1]

Ok, Thorpe. I just drained the oil and checked that pin, it is in tact and in good shape.

Chopsaw, Yes the spring is in there.

Keepah Rolln, I am running 10w-40 engine oil.

I really truly appreciate the help I am getting on this thing. This ES has been a trouble maker from the start!!

[atc007]

It needs a tranny. Tear into it or find a good used one. :(

[just ben]

I agree with 007. If it were a clutch issue, it would affect the higher gears more than the lower gears. You are in luck though, I should have everything you need and will sell it cheap.

[hatc200x1]

This ain't looking good. At least i had bought the complete gasket kit from when I replaced the timing chain. Another issue, this machine does not smoke, when I pull the top end to split the crank case, can I just hone the cylinder and slap the same rings back in? Thanks! I really wonder why someone would take the original ES engine out, and put this none working TRX 250 four wheeler engine in there.

[just ben]

Rings are cheap,I would replace them

[Thorpe]

Agreed!^^ I have an 85 SX motor and trans I will sell you... Even free delivery! Comes with a 85 SX attached though...

[hatc200x1]

Update here guys. I just totally disassembled the engine. There is absolutely no damage to the transmission gears!!! They are all in good shape! It was a fun tear down but what else could be the issue? I took apart the output shaft on the engine and the small differential in there is in great shape as well. I'm starting to lean torward's clutches but its not a slip, it is a SKIP when it happens.

[just ben]

I'm gonna go with a bent or worn shift fork.

[atc007]

^^ Yep, and this one will take a close eye. But you have worn/bent forks,and will be able to see EVER so slightly where your gears aren't meshing right. If you can't definitevely tell what's wrong. Set your fresh top end on a known good lower.. this is a rare problem in these bikes.. Clutches WOULD have slipped awful in 3rd 4th and forget 5th! I know it's frustrating. But you're staring at the problem lol..

[hatc200x1]

Found some damage on some of the of the "tabs" on the side of the gears. I can't see a bend in the shift forks, but I'm assuming bent shift forks would cause the damage on the tabs? Thanks for all your guy's help so far. Pics below. Most of the "tabs" have a flat corner like shown.

[350for350]

PM Jim (FlyinW). He seems to know a lot about these trikes.

[Flyingw]

Those impact marks on the sides of those gears is not uncommon however, that one is pretty significant. That's caused by the rider not letting off the throttle when they shift and more than likely, the clutch was out of adjustment as well. In any case, you can take a file and gently blend the rough edges and smooth them out but that one gear and its mate, I would suggest replacing them.