140 Assassin 3rd gear sliping

[jimbo jones]

I'm looking at buying a 140 assassin and the owner says it has a problem with 3rd gear and it sometimes acts like it slips what would be the problem with it and can it be fixed or will it need a new gearbox?

 

[my67xr]

yeah i'd be guessing it will need the engine pulled down, split the cases and i reckon that one of the gears' dogs would have broken off. it needs a new gearbox at a guess.


but it could be a worn shift drum too, which needs the engine pulled down/apart too.

here is a rebuild video to give you a bit of an idea

[video=youtube;xo0k6fUHTC0]http://www.youtube.com/watch?v=xo0k6fUHTC0[/video]


and splitting a YX140, pretty much the same engine as the one you're looking at
https://www.scribd.com/doc/45909077/YX140-Engine-Split

 

[jimbo jones]

Thanks mate your always helpful

 

[jimbo jones]

I have a 110 motor and box sitting here would the gears be the same do you think I could swap the 3rd gear over?

 

[my67xr]

i'm pretty sure the gears/gearbox's wont interchange due to different sized shafts.

 

[jimbo jones]

Ok cheers can you buy replacement gears for them?

 

[my67xr]

Yeah ebay etc has them listed.
140 pit bike gearbox | eBay

you might need to replace the shift drum at the same time (that might be all that is wrong with it ?)

and don't forget to order a full gasket set too for it

Is it a Lifan or YX?
Can you get the engine model number off it ?
It is stamped into the case below the front spocket

 

[jimbo jones]

It's a yx I'll have a look I just picked it up

 

[jimbo jones]

Is that all I need

http://pages.ebay.com/link/?nav=item.view&alt=web&id=120700392293

 

[jimbo jones]

This is the number on motor

 

[my67xr]

sounds like it could also be a Lifan 150 ?
do you have any pics of the other side or the engine, something with the clutch cover and head ?

does it look like this ?

or like this ?

 

[jimbo jones]

Top pic is my motor. also I have no clutch it's like the cable is way to long the old owner thought it was snapped but it intacted seems like it isint pushing the pressure plate in far enough.

 

[jimbo jones]

Im pretty sure its this bike

Assassin A-6R 140cc YX Big Bore BLACK 12'' Rear 14'' Front, Assassin Dirt Bikes

 

[my67xr]

ok, on the rear of the cable bracket on the engine, do you have a concentina rubber boot there ?
if so, pull it back towards the clutch arm coming out the cover.
you should see a lock nut there, undo the nut and wind it away from the adjuster.
then do up the nut at the front of the adjuster to take up most of the slack


so with that clutch actuator arm that comes out the side cover, you want there to be about 3mm movement forwards, before you feel resistance, eg till you can feel the clutch starting to engage
you should be able to move it with your hand.


it could also be possible that the clutch cable is stretched too? or not adjusted up at the clutch lever

 

[jimbo jones]

I checked all that last night it's like its 2cm out of adjustment and there isint enough thread to take it up Could be something to do with the clutch it's self I'll have to investergate it when I pull the box down

 

[my67xr]

ok, try this
loosen the cable lock nut's down the bottom on the engine mounting bracket, undo the front nut about 4 or 5 threads, and unscrew the rear lock nut off the bottom of the cable.
now unhook the cable end from the arm and take the cable out of the bracket.
put the rear lock nut back on and wind that back up the adjuster so it is sitting against the front nut
refit the cable and take up the slack by adjusting the rear nut against the cable bracket.
make sure the clutch arm can still move 3mm or so so it doesn't ride the clutch.
when you are happy wind the front nut back down and using 2 spanners lock the 2x nuts together.

this should take up the cable slack, and let you be able to test the clutch better.

try the clutch out now and see if it works through the gears etc


sound's like someone has fitted the wrong length cable at some stage ?

 

[jimbo jones]

The bike is only 6 months old can't see the cable being changed already I'll try it out and let you know.

 

[jimbo jones]

I tried adjusting it and it feels like I have a clutch there but when I start it and pull the clutch in and put it in gear it just stalls must be more to it.

 

[my67xr]

Ok,
So next step is to drain the oil.
Pull the kick start lever off, disconnect the clutch cable and take the side cover off.
It might have a loose clutch castle nut.
Its behind the outer bearing plate.

 

[jimbo jones]

it will have to be put on hold for the time being till Im ready to strip the gear box