Fork Oil 10W


F

FastFreddy

New Member
I finally changed the front fork oil to 10W and lowered the head stock 5 mm.

For the quick ride after I checked everything, it feels more balanced and settles into turns quicker with more grip while settling. It feels like you don't have to load up the front as much to get a similar turn result. I have to get used to braking without it lurching forward like granny's rocking chair. Braking feels like its crouched down a touch already, ready to go. Over speed humps there was no problem, just felt more settled, not hard, not pumping too fast. I left the rear shock as is, on 4, and it feels balanced for my weight, 88 kg last check.

Just a touch different from stock settings, and feels like a good improvement if you still like it a bit soft with better turning.

I worked out you have to lever a flathead on the lower fork clamps for the forks to slide out.
 
F

FastFreddy

New Member
On stock springs, the cap comes off gently if you have the front end suspended, I was kinda expecting it to come flying off, but no dramas.
 
J

JT

Monster Member
Elite Member
Freddy. can you assist me with a how to change this out yourself?


im a noob regarding fork oil and how to DIY, either a few steps or a link would be great
 
F

FastFreddy

New Member
I gathered that the stock fork weight was either 0 or 5W.

I wanted to keep the front fork softish, so went with 10 W.
I was concerned I'd have to go too hard on the rear if I went any harder on the front. I'm aware that going too hard on the front will make the bike difficult to turn unless you also go hard on the rear.

10 W feels right to me for the street. Not hard, not soft, just like Goldilocks in the baby bears bed.


By dropping the forks 5 mm at the same time, it balances out the fork going slightly harder. (Hard fork makes it slower to turn, increased rake makes it slightly easier)

---------------

How to steps :

Needed :
- Grease for front axle
- Trucking strap to lift front wheel up. Or front wheel stand.
- 22 mm socket for front strut caps
- 19 mm spanner/ratchet for axle.
- 8/12mm socket needed for brake line bracket and front brakes
- clean rags.
- Good set of metric hex keys. (4,5,6,7mm confirmed used)
- Measuring flask (with clearly marked 450 and 500 mL lines)
- small funnel

I won't give a blow by blow procedure, just some tips.
I basically followed what the Technical manual said and looked at the pictures for the torque settings for the most part. ( I didn't use the torque wrench as I've got experience so can go by feel, I was aware of the settings but did by feel as it was getting dark so I had to move quickly) (ie : firm : handlebars, brake bolts and axle, medium : pinch bolts, fender bolts etc.) I noted the pinch bolts were done up harder than the factory torque spec would suggest so I did these up with medium firmness rather than soft. (Use a torque wrench to get the feel)

1. Secure the bike. Rear stand lifts up the rear wheel, trucking strap to lift the front wheel. (front wheel stand better as straps aren't meant to be used for lifting motorbikes)
- used a strap that was wrapped underneath where the frame joins the headstock to lift the front up 1 cm (1/2 inch) off the ground. Make sure you aren't pinching any wires or brakes lines etc.

2. You want to loosen the front caps off the forks before you take off the forks. Take the handlebars off their caps and move out of the way. (I used a 22mm spanner, but would recommend you purchase a specific socket for this) Perhaps loosen the first turn with a spanner before removing the handlebars so you have something to lever with, then use a socket to undo.

3. Remove per side at front end - 2 front brake structural bolts. 1 Fender screw, 1 brake line bracket/fender screw (nut will drop from inside the front fairing).
Use string or fencing wire to hold the brake calipers out of the way. Undo the horn and move out of the way so you can see up there. Remove front axle and remove front wheel (Note the spacers). Clean axle with rag and kero, then put on grease before reassembly later.

TIP : Make sure to study the layout and orientation of the brake lines, there are 2 line holders that plug into a bracket on the left hand fork. I had to pause during re-assembly to work this out. Pictures are in the workshop technical manual.

4. Now the forks are ready to be removed. Take out the upper and lower pinch bolts. The forks will stay in place, I had to use a big flathead screwdriver to lever the lower clamp, then the fork would slide down and out easily. Clean the outside of the forks with a rag. With no load on the fork, the top cap will come off with a minor pop. (clean hands again before opening) Place the cap in a clean place so that nothing touches the inside. Then hold your hand on the fork and drain the oil out by tipping upside down into a clean bucket, place gently upside down in the bucket against a wall, then get the other fork and do the same. Give them a few pumps while holding firmly with both hands and the fork still upside down.

TIP : The spacer, washer and spring will fall out if you tip upside down without holding them in place. They go back in after cleaning in any case.

TIP : The left fork leg has a wire held in place by a plastic clicky strap (what are they called ?). During re-assembly, you have to put the fork in half way, slide the plastic strap and wire in place over the fork, then put the fork in all the way. (It was probably the horn wire, I didn't check)

I reassembled the forks onto the bike before I refilled the fork oil, there was less chance of dirt getting in there this way. (seems like you'd need 3 hands to do it off the bike)

Now, measure out 473 ml of 10W oil in measuring flasks. Make sure the flask is on a level surface. You have to use your eye here to be accurate given the lack of graduated lines on most measuring flasks. Halfway between 450 and 500 and a few drops less. ( I used cooking measuring flasks and funnel as they were cheap and brand new)


Undoing the strap, err, at this point you think, "I don't want my finger to jam in that mechanism while undoing the strap", so pinching the 2 sides of the strap together while shoving a newspaper and some cardboard under the front tyre took the load off the strap for safety.
 
Last edited:
B

bleedinblue

Senior Member
Elite Member
FastFreddy said:
I gathered that the stock fork weight was either 0 or 5W.

I wanted to keep the front fork softish, so went with 10 W.
I was concerned I'd have to go too hard on the rear if I went any harder on the front. I'm aware that going too hard on the front will make the bike difficult to turn unless you also go hard on the rear.

10 W feels right to me for the street. Not hard, not soft, just like Goldilocks in the baby bears bed.


By dropping the forks 5 mm at the same time, it balances out the fork going slightly harder. (Hard fork makes it slower to turn, increased rake makes it slightly easier)

---------------

How to steps :

Needed :
- Grease for front axle
- Trucking strap to lift front wheel up. Or front wheel stand.
- 22 mm socket for front strut caps
- 19 mm spanner/ratchet for axle.
- 8/12mm socket needed for brake line bracket and front brakes
- clean rags.
- Good set of metric hex keys. (4,5,6,7mm confirmed used)
- Measuring flask (with clearly marked 450 and 500 mL lines)
- small funnel

I won't give a blow by blow procedure, just some tips.
I basically followed what the Technical manual said and looked at the pictures for the torque settings for the most part. ( I didn't use the torque wrench as I've got experience so can go by feel, I was aware of the settings but did by feel as it was getting dark so I had to move quickly) (ie : firm : handlebars, brake bolts and axle, medium : pinch bolts, fender bolts etc.) I noted the pinch bolts were done up harder than the factory torque spec would suggest so I did these up with medium firmness rather than soft. (Use a torque wrench to get the feel)

1. Secure the bike. Rear stand lifts up the rear wheel, trucking strap to lift the front wheel. (front wheel stand better as straps aren't meant to be used for lifting motorbikes)
- used a strap that was wrapped underneath where the frame joins the headstock to lift the front up 1 cm (1/2 inch) off the ground. Make sure you aren't pinching any wires or brakes lines etc.

2. You want to loosen the front caps off the forks before you take off the forks. Take the handlebars off their caps and move out of the way. (I used a 22mm spanner, but would recommend you purchase a specific socket for this) Perhaps loosen the first turn with a spanner before removing the handlebars so you have something to lever with, then use a socket to undo.

3. Remove per side at front end - 2 front brake structural bolts. 1 Fender screw, 1 brake line bracket/fender screw (nut will drop from inside the front fairing).
Use string or fencing wire to hold the brake calipers out of the way. Undo the horn and move out of the way so you can see up there. Remove front axle and remove front wheel (Note the spacers). Clean axle with rag and kero, then put on grease before reassembly later.

TIP : Make sure to study the layout and orientation of the brake lines, there are 2 line holders that plug into a bracket on the left hand fork. I had to pause during re-assembly to work this out. Pictures are in the workshop technical manual.

4. Now the forks are ready to be removed. Take out the upper and lower pinch bolts. The forks will stay in place, I had to use a big flathead screwdriver to lever the lower clamp, then the fork would slide down and out easily. Clean the outside of the forks with a rag. With no load on the fork, the top cap will come off with a minor pop. (clean hands again before opening) Place the cap in a clean place so that nothing touches the inside. Then hold your hand on the fork and drain the oil out by tipping upside down into a clean bucket, place gently upside down in the bucket against a wall, then get the other fork and do the same. Give them a few pumps while holding firmly with both hands and the fork still upside down.

TIP : The spacer, washer and spring will fall out if you tip upside down without holding them in place. They go back in after cleaning in any case.

TIP : The left fork leg has a wire held in place by a plastic clicky strap (what are they called ?). During re-assembly, you have to put the fork in half way, slide the plastic strap and wire in place over the fork, then put the fork in all the way. (It was probably the horn wire, I didn't check)

I reassembled the forks onto the bike before I refilled the fork oil, there was less chance of dirt getting in there this way. (seems like you'd need 3 hands to do it off the bike)

Now, measure out 473 ml of 10W oil in measuring flasks. Make sure the flask is on a level surface. You have to use your eye here to be accurate given the lack of graduated lines on most measuring flasks. Halfway between 450 and 500 and a few drops less. ( I used cooking measuring flasks and funnel as they were cheap and brand new)


Undoing the strap, err, at this point you think, "I don't want my finger to jam in that mechanism while undoing the strap", so pinching the 2 sides of the strap together while shoving a newspaper and some cardboard under the front tyre took the load off the strap for safety.
Click to expand...
Nice repp worthy write up :D thanks alot its a task I've had on my mind/been looking into.

What about burping the air out of the new oil?
 
W

WeatherB

New Member
bleedinblue said:
Nice repp worthy write up :D thanks alot its a task I've had on my mind/been looking into.

What about burping the air out of the new oil?
Click to expand...
Yes, you also need to move the forks up and down to remove the air bubbles.

One last note, when measuring the fork oil, you do it without the springs installed by the way.
 
F

FastFreddy

New Member
Drawbacks.

As we know with suspension and engine tuning, you gain in some places you lose in others.

The only drawbacks I've noticed so far are :
- less weight transfer under brakes, as there is less of an initial dive. Therefore potentially less braking force, however the braking effect seems to come on quicker with less of an initial dive, so it works out similar.
- When hitting cateyes on the road with the side of the tyre, there is more headshake than before. The bar twitches in your hand more with more rake. Nothing drastic.

Technical drawback (I haven't felt this yet as I'm not riding hard enough) :
- I heard bikes setup flat (not raised at rear or lowered slightly at front) will finish off the turns better. Can put more power down without running wide.
I'd have to be going at race pace to notice this one. However, it seems to corner better anyway.


Overall, lowering the front will help you go into the turns more than the exits.

With anything like this, you are after the balance between front and rear, between stability and chuck-ability. Go to far either way, then you either have to wind it back or do another mod to compensate.

I'd recommend minor changes from factory spec for anyone interested in playing with suspension. It's not like we have a test track in the back yard like Lord March at Goodwood or the ex-Coca Cola CEO at "The Farm", but I wouldnt' rule that out for myself one day (you never know), you'd have to buy a Bimota or something if you could afford your own racetrack.
 
F

FastFreddy

New Member
Fork Oil level :
I heard you can change the fork oil level to suit, but if you put too much in there you'll top out and damage the fork. The air cavity acts as a spring in the fork, so the lower the oil level, the stronger the air spring so to speak.

I simply measured the exact fork oil out (473 mL) and poured in and inspected to make sure it was the same level as before.

Air bubbles :
I pumped the forks up and down several times, then went for a test ride, riding slower than normal. Then I test hit a few speedbumps to make sure I hadn't gone to hard.

The first pump of the forks seemed to move a lot while the air was still in about the valve mechanism.

Next :
I have to go to the twisties to test if I've lost anything coming out of corners.
I also want to try setting the preload on the rear to 5.
I like a softer setup with lots of movement and feel normally, 5 seemed to much preload for me previously.
 

Bert-Aus

Bert-Aus

Well-Known Member
I have my rear preset to 6 to perch the rear slightly,
Forcing the suspension to always force slighty forwards and ensure rear wheel maintains contact, especially under heavy braking.
Keep in mind I haven't changed up the fork oil.
And I am only 5'11" @ 80kg, in which case I noticed my rear would bog down too easily and bottom out sometimes. Which had my liscense plate catch on my wheel

Sent from my LT18i using Tapatalk 2
 
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