hi guys welcome back to Mini Bikes Store video blog today I'm gonna show you how
to replace the both sprockets and the chain on the 125cc midi quad so here you
can see on this quad the quad was stored for a long time outside the chain is
very rust needs to be replaced also the sprocket is damaged you can see
the rear sprocket is damaged and the front one as well so they both
sprockets and the chain they needs to be replaced
so first you need to actually order the proper parts before you start replacing
them so when you look close at the sprocket I hope you can see there is a
number on the sprocket at the rear which here it says 420 by 37 so its mean
it's 37 tooth the sprocket and you have to order the same sprocket so here we
have the new one order it as you can see it's 37 by 420
so that's the correct size so when you look at the front sprocket there is also
a number on it which is here it's 13 t by 420 but it's mean that there is 13
teeth so you can order the parts by the numbers or you can actually count the
tooth and make sure you get the proper ones and then you just order the chain
it's good idea if you get the extra split link so if you need to make the
change shorter you can use the split link so now I will show you step-by-step
how to properly replace them so first we need to remove the old parts as you can
see here everything is rusted the quad was stored outside for a long time so
it's good idea to spray wd-40 on all bolts and screws you will be removing
I will also remove this cover so you can clearly see what I'm doing but you don't
have to do it so first you need to remove the rear wheel the left-hand side
so remove the pin which secure the nut
and now unscrew the nut
and remove it
remove this pipe here now we have easy access to the sprocket so we need to
unscrew this four bolts which holds the rear sprocket and this two here at the
front which hold the front sprocket if you need to hold the wheel because it's
turning as you can see you can put the screwdriver into one holes of the brake
disk and it will lock now so you can now unscrew that bolts
the second one
before you remove the rear sprocket you should loosen these two bolts which holds the
the front sprocket because we have the wheel stopped here in the disc brake so
this won't move as well if you remove the chain you won't be able to unscrew
these two screws so first loosen them like this now you can remove all the
bolts from the rear sprocket
and remove the rear sprocket next remove the chain from the front sprocket
and you can remove both bolts which holds the front sprocket
here is the front sprocket the last step is to remove the chain you will find on
the chain that there is a split link is just here one just one here so you
need to remove the split link open the chain and then you will be able to
remove I will spray it will wd-40 because it's rusted
so I have removed the split link and you can see the chain opens now so you can easy
remove the chain so we have all the parts removed now and we have to instal
the new ones so here we have all the new parts here's the front sprocket the rear
sprocket here in this bag we have bolts to install the front sprocket and
and security plate here in this box we have the new chain
here is the new chain
as you can see if this chain is very very long but it's much better that you buy
the longer chain than too short so we need to make this chain for size so I
will show you how to make the change for size it's better that you order longer
chain that is too short so first we need to instal the front sprocket so make
sure the number which is 13T on these site it's from outside put the
sprocket in position like this then place the plate to secure it then twist
it and insert the bolts I do recommend that you put thread lock on these bolts
and the second one
you won't be able to tighten it because you will see it will be turning so we
will tighten all the bolts at the very end when we have the chain installed as
you can see they are moving so next install the rear sprocket you have to
also make sure that the number which is on the sprocket it's only one one side
on the other side there is no number so the number has to be from outside place
the sprocket in place and secure it with the bolts also if you have the thread
lock you can use the thread lock on them
here we have one
next you can move the screwdriver here and place it here on the top and now it
will lock so you can tighten all four bolts
so next step is we have to make
the chain to the size so you need to find on your new chain the split link
it's just located just here so put the old chain in this position like
this and then put the new one next to it put the split link exactly in place
where the chain was open the old one see we open it here so here is the split
link put it next to it up to the end
and then
and then put the new one exactly as you can see we have exactly the same place
them exactly the same so the amount of the links will be the same and we need
to open the chain exactly in this place and then the new chain will be the same
size as the old one so you can mark this place
you will need to open this link so
you need to polish the top of it
you can also polish the next one here this one here so it will be easy to
open it
now wait a few minutes it can be very hot when the chain will cold down you need to
remove the top link here like this see and we have the chain open now
so here is the split link you need to now open the spit link
here is the chain which
was too much next you need to put the chain on the sprockets
so on the front one like this then on the rear one and you need to place the
chain like this insert the split link through it
then the plate
and secure it with this little security plate
like this so we have replaced sprockets we have the chain made to size and now
we can adjust the chain to adjust the chain you need to loosen this bolt here
this one here this one and this one here on this side and then you can use the
chain tensioner so when you loosen these or bolts you can move the axle back and
forward so we need to adjust it by turning this two screws when you adjust
the change you need to make sure that the sprocket is straight both sprockets
are in one line so when you pull this side into the back the sprocket will
move like this when you pull more this side the sprocket will move to this side
so I need to make sure that the sprocket is in one line with the front one as you
can see here the sprocket is moving a little bit so we need to instal the
wheel to make sure the sprockets fits in the in the position
so install the wheel now
secure it with a nut
and tight it well
so we have the chain adjusted and you can now tighten all the bolts here
so this is how step-by-step you replace both sprockets the front one and the
rear one we have also replaced the chain we have made the chain to the size
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