Honda Forza 300 Coolant Replacement
To access the radiator cap:
- Remove the right side body cover (this is necessary so you can do the next step)
- Remove the front side body cover
To access the water hoses:
- Remove the left floor mat
- Remove the left floor skirt (although removed here, it is not necessary to remove the left slide body cover or the left front side body cover.)
To access the coolant reserve tank:
- Remove the right floor mat
- Remove the coolant reserve tank access panel on the right floorboard. (Although removed in the picture, it is not necessary to remove the right floor skirt.
To drain the old coolant:
- Remove the radiator cap
- Put a pan under the drain bolt to catch the draining coolant.
- Remove the drain bolt and sealing washer. (Note, this is readily viewable/accessible without removing any paneling. Thinking this area had to be hidden I removed extra panels looking for it until I realized it was already staring me in the face.
Disconnect the water hoses:
- Put a pan under them to catch the coolant.
Siphon out the coolant from the coolant reserve tank.
Filling with new coolant:
- I used Peak Long Life 50:50 Antifreeze/Coolant
- Reconnect the radiator hoses
- Install a new sealing washer and put the drain bolt back on and tighten. (I reused mine, but reversed the washer).
- I couldn’t find the torque setting so I used the same as for the final drive drain bolt which is 10 foot-lb
- Fill coolant reserve tank to the upper-level line. (150 ml)
- Replace the reserve coolant tank cap and the reserve tank maintenance lid.
- Remove the air bleed maintenance lid of the luggage box
- Remove the air bleed bolt and sealing washer (be careful not to drop/lose them).
- Fill the coolant from the filler neck until the coolant starts dripping from the bolt hole. (Have a spotter watch for the drip or just listen for it. It will just drip on the floor and not mess up your luggage box.)
- Stop filling and install the air bleed bolt with a new sealing washer. (I just reversed the washer).
- Install the air bleed maintenance lid.
- Fill the system up to the filler neck. (1350 ml, not including the 150 ml for the reserve tank) (So you will need about 1500 ml total plus whatever overflows from the air bleed bolt)
Bleed Air From The System
- With the Scooter on the center stand and the radiator cap off, start the engine and let it idle for 2 – 3 minutes. Snap the throttle 3 – 4 times to bleed air from the system.
- Stop the engine and check the coolant level.
- Add coolant up to the filler neck.
Finishing up
- Put the left floor skirt on.
- Put the left floor mat on.
- Put the radiator cap on.









5 Comments
Justin · October 3, 2019 at 10:10 pm
How did you go about removing the side panel to access the cap for the coolant? I’m trying to run some wires through the bike to the battery and I’m struggling with some of these panels.
tyurinalexey · October 31, 2018 at 12:52 pm
How much coolant you need to put in your forza once replaced coolant?
asolof · October 31, 2018 at 7:15 pm
Thanks for asking. I should have included that. (1350 ml, not including the 150 ml for the reserve tank) (So you will need 1500 ml total plus whatever overflows from the air bleed bolt).
I updated the post to include it.
Yannick · October 5, 2019 at 12:21 pm
Thank for your your explanation, but could you explain how to remove the right (left) side body cover ?
I’ve try but it’s seems not so easy…
Yannick
asolof · October 5, 2019 at 1:42 pm
First remove the floor mat then the right floor skirt.
Get the service manual: https://www.ebay.com/itm/Honda-2016-Forza-300-NSS300-Service-Manual/293165814081?hash=item44420b5141:g:Xh4AAOSwI4BdOy0F