How To Change Motorcycle Fork Seals (Shock Oil Seal Replacement)

Hello and welcome to the episode, today I show you how to replace the fork seals on a Honda nc750x, this covers years 2013-2016, newer models are very similar but oil volumes may vary, so please check first.

First thing you should do is loosen the 17mm top caps as shown

dont unscrew them all the way, just loosen them half a turn

now with a 5mm allen key, remove the mud guard as shown

use a 8mm socket to remove the brake hose clamp, do the same on the opposite side

carefully lift mud guard off

using a 12mm socket remove the brake calliper, rotate the disc so it lines up with the cut out to help the calliper slide out, now tie the brake calliper out the way

remove the spindle pinch bolt with a 12mm socket,

place all your bolts in pot so you don't loose them

using 17MM hex socket, loosen the wheel spindle

using a block of wood and a trolley jack, ease the pressure from the front buy placing it under the sump, you wont need to put much pressure here providing your bike is on its main stand

remove the spindle bolt, remove both spaces and keep them safe

using a 14mm socket loosen the shock pinch bolt, now loosen the top pinch bolt

carefully slide the shock out

do the same on the opposite side

using a 6mm allen key on the bottom of the shock, jolt the bolt with a quick action, just loosen half a turn for now

while applying downward pressure remove the upper cap gently,

tip out the old oil and remove parts as shown, make sure you do this on a clean surface

now clean all the parts thoroughly

gently remove the dust seal with a flat screw driver, now remove the inner oil seal retainer

unscrew the lower allen key bolt completely

now separate the shock as shown,

remove the inner spacer

now remove the old seal

clean the bushes and use some auto sol on the shock tube, do not use anything abrasive

check the shock tube for any cracks or damage and clean,

insert the spacer shown

I use some waste pipe and an exhaust clamp to install my bush and seals, this works fine and will save you money on buying a special tool

slide the tool over and clamp it in place

now tap downwards jolting the bush in place, you will hear a change in sound when its seated

using a cut up milk carton smear it with grease , fold it round the end of the shock tube making a cone shape, now gentle slid the seal on, check seal orientation before installing, slide all the way to the bottom

now use the old seal and place that on top, we will use this to drive the new seal in place, using the home-made tool nock the seal in place as shown

again you will hear a change in sound when its seated

reinstall the seal retainer, be careful not to touch the rubber seal with the screw driver

now install the dust cover and push in place

insert the fork piston as shown

clean the old screw and tighten to 20nm, use the spring to stop the piston from turning inside

fill shock with 10w oil, leaving a 101mm air gap, I used 500ml in each shock and this was spot on

work the shock up and down to remove bubbles and recheck air gap, the air gap should be measured when the tube is fully extended, here are the illustrations

now slide the spring, spring seat and collar in as sown

now install the top cap pushing downward at the same time, tighten so its flush

install the shock, making sure the top cap is sticking out as shown

do the same for the other side, tighten the lower pinch bolts to 39NM

now tighten the top cap to 22NM

do the same for both sides

now tighten the upper pinch bolt to 22nm

grease the wheel spindle, install the wheel and the pinch bolt, tighten axle to 74nm, then tighten pinch bolt to 22nm

now carefully install the mud guard,

install the calliper and tighten bolts to 30NM

remove trolley jack and pump the front brake so settle the pads

check the suspension operates correctly and there are no leaks

now clean the brake disc and wipe all the areas where you have worked



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My gear:
GoPro Hero 8 with media mod
Purple Panda Mics
Video Editing - Vegas Pro 15
Samsung Galaxy S20

My Bike:
2020 Honda NC750X

Location, UK