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Tx 240 engine


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Hello everyone

Today I started up the tx 240 for the very first time

she pinged into life after turning the air screw about 1.5 turns out and idled just fine 

what a beautiful lazy engine in comparison to my bonkers kx125 and all those horrid chainsaws I have been fixing recently to make a bit extra.

not much to report 

have to source a few parts mainly a clutch lever, bars, chain, and some kind of air filter.

Does the clutch cable just attach to an arm of some type to push the clutch? Should there be a rubber to keep dirt out between the clutch cover and the cable . Or does the cable fit in and seal itself in.

we can say there is one more aprilia tx about now. Thanks to the effort and skills of many people.

Be safe everyone. Keep riding.

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Yes I'm very happy with the results and progress

 I'm working at her this Saturday so I'll take a picture 

so the clutch assembly attaches to the case and unless you take it off on purpose it remains in place say even  if you remove the side cover to work at the clutch , is that correct?

And the cable connects to part number 7 is that correct?



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Got the clutch working

Was unable to select a gear but the 2 shafts are turning free inside the gearbox 

It's either stuck in neutral or in a gear

I think it's the shift mechanism causing the bother the gearbox is good on this one

Hopefully take the side cover off and something might be obvious. Just a case of examining closer.

Got new bars on and the clutch working so that's ok just the shifter mechanism.

EDIT= I searched the internet and it's looking more like a case split job. Martinswm talks about a tensioner arm jamming behind the shift barrel and This seems the most likely thing. This would explain why it's in neutral. I can imagine such a thing from my kx125 build. Can I use the old crank seals or do I need new seals? I don't want them to fold over when removing the crank and shafts. When this is done she will run.

Edited by Kdtx240
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Just a quick update

Have the cases starting to split.

The front half is very tight and stubborn. It's starting to go but I'm not taking any chances. I've ordered a case splitter tool. There won't be much progress until this arrives. 

Flywheel put up a fierce battle too.

Might be a fortnight yet.


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  • 3 months later...

Great, hopefully you can ride it again in the next time; always good to hear that old stuff got running again.

Did you just got a new ambos or too the tiny spring and ball, then I recommend a very good allen bolt in high tensile steel, to fasten the ambos of the kick starter and a god stop washer, the fastening of the Rotax engine can be delicate.

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  • 4 months later...


After a full strip and rebuild i am having a problem

The gears are selecting as I can hear them click and I checked them before continuing the engine however i have no drive. The clutch also wanted to move the bike forward when pulled in. It is almost as if the drive was not getting to the input shaft of the gearbox. New clutch plates were fitted and gears were all ok with no broken teeth or dogs. A bearing was replaced on the gearbox shaft.

I cannot look at the bike until Monday evening. I would appreciate your input.  

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There are two plastic plugs on the clutch casing, remove the rear one and check the adjusted has slack, ie clutch isn't effectively engaged. Check there is also slack at the lever.

Generally the issue with these engines is the clutch won't free off.  What oil is in the gearbox ?

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Correct, cable may be slack but mechanism still partly engaged.

Atf is good, but check you have enough oil, there is a level screw in the casing behind the gear lever. From memory it's 1200ml.

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The level screw is approximately in the middle of the case- looking at it wouldn't suggest it holds the case on is that right?

Is there a way of adjusting the clutch mechanism other than the cable?

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11 hours ago, Kdtx240 said:

The level screw is approximately in the middle of the case- looking at it wouldn't suggest it holds the case on is that right?

Is there a way of adjusting the clutch mechanism other than the cable?

Level screw is behind the gear lever as previously mentioned. Clutch adjusts behind plastic plug, take it out and you will see.

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Thanks that worked it was found the clutch was continuously engaged as advised.

took the bike a quick spin as the evening was coming to an end and it seems quite acceptable

Hopefully have all the gears, definitely 123

The front shocks need redone, with corrosion of the chrome causing the seals to fail. How can this be fixed?

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  • 1 year later...


The bike bogs down after quarter throttle and creates a lot of smoke under load.

It starts and idles fine and will start first kick when hot, 2/3 kicks on choke cold, and if its lay up for a month it will need a spray of starting fluid but always starts

I have tried to adjust the fuel screw and needle height and even replaced the needle for an X2 and needle jet for i think av266 or As266

engine revs crisp in neutral, I had thought it was running good and was surprised when it bogged so badly

starting to think it could be the condenser but my only reason to back this is a post I read about a users bike "4 Stroking" and bogging they replaced the condenser and problem solved.  I do have a good spark it can be seen and heard. 

Another user posted how to mount the new condenser under the tank. Does the flywheel have to come off to fit?

I don't want to start accumulating carb jets and I feel the timing is ok as there is no detonation 

I used the bike to feed sheep all winter due to the low gears and I didn't rev the engine so just got by this way. now I need the revs to round up the sheep.

the plug is a rich condition oily petrol mix black.

the airbox is missing a basic filter is mounted but this would mean more air and possibly a lean condition so its not that.

please advise easiest or best way to mount new condenser or suggestions welcome

best regards


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