Fork oil change

[Kingston]

Can anyone tell me when you should change fork oil? The amount per fork and the weight?
2004 919

[beefsalad]

Originally Posted by Kingston

Can anyone tell me when you should change fork oil? The amount per fork and the weight?
2004 919

463ml of SS-8 (5w) should leave your oil level 155mm below the top of the fork. As far as a suggested interval Honda does not give one...they only suggest inspection every 8k miles. Racetech suggests changing every 30-50hrs of use, but I'm sure thats to keep the bike in race-ready condition.

[nd4spdbh]

Originally Posted by beefsalad

463ml of SS-8 (5w) should leave your oil level 155mm below the top of the fork. As far as a suggested interval Honda does not give one...they only suggest inspection every 8k miles. Racetech suggests changing every 30-50hrs of use, but I'm sure thats to keep the bike in race-ready condition.

you really cant go by measured volume it will get you close but the proper way for our forks is to measure from the top to oil level.

myself personally went with some 10w maxima RACING fork oil at a height of right around 130mm from the top (a lil higher than stock) to increase the air spring rate and help with front end dive a lil. definitely made the front end feel much more planted.

i replaced the fork oil in my forks simply due to a bad fork seal that i replaced .... this was right round 4k miles.... i guess one of the fork seals got damaged by some dirt early on.... done 12k miles since without probs.

how many miles you have on your bike?

[Kingston]

The 04' 919 has 24,000 Km. and it is the original oil. The forks work fine so I guess I will stick to the 5wt. oil. I just change the fork oil in my 1985 Yamaha and it was black. I just got the Yamaha so I don't know how many miles were on that oil.

[nd4spdbh]

id say when you hit 32k KM or 20k miles change the oil. And FYI service manual for the 919 calls for honda ss-8 fork oil... which is 10w.

[beefsalad]

Oops! my error...thanks for pointing that out.

[rickard919]

I ran my OEM oil for about 80k miles with no problems. Your call.

[nd4spdbh]

Originally Posted by rickard919

I ran my OEM oil for about 80k miles with no problems. Your call.

yes but you also run engine oil for half as much.... ur crazy (i think it was u).

id say 20k miles on fork oil is about where ima change it at.

[boogunoogun]

if your gonna open up your forks, it might be a good time to replace the springs with something suited to your weight. Unless your fine with the front suspension. I found that it was too mushy and any time I hit the front brakes I'd do a nose dive. Traxxion Dynamics makes a sweet kit with precut spaces for a little above $100

[zaq123]

depends how you use/abuse your bike and riding conditions (dirt/dust/water/heat/cold etc)
I wouldn't go longer than 10k miles or 2 years. If riding in the dirt/dust/rain sometimes, I would do it every year or if bike stored outdoors.

Fork oil breaks down when its additives are depleted and it's contaminated with aluminum and bronze debris. Additives that make oil to have a low flow resistance are polymer particles and they eventually accumulate as a varnish like coating on the inside of the forks tube.
The main source of debris are spring flakes, wearing out bushings, preload washer rubbing against nut and spring, aluminum shavings. You will be surprised how dirty your oil is after 10k miles and how much crap is deposited on for tubes or cartridge.
Some good quality springs have a flexible polymer coating that resists flaking. Another good reason to install a good set of springs.

Can you ride your bike for 100k without changing oil? Most likely yes, unless it leaks out in the process. Should you? It's up to you.

[mcromo44]

Use 10W dedicated fork oil.
Use good stuff.
Set by oil level and not volume added.
Suggest not using the stock oil level.
Instead, regardless of what springs you have, stock or aftermarket, use no more than 140 mm and no less than 125 mm.
For those spooked off by deciding what to use out of the above range.
If you feel your bike is really divey on the brakes, because you really use the front brake, go 125.
If you have stock springs and think things are OK as they are, go 140 and you'll avoid "clanging" when you find yourself giving your front brakes a fist full during a $ 1.10 moment.

[zaq123]

I wouldn't go with much more than 125. Maybe 5 mm max. If you need 140, you should look into other parts. Oil level should be used to fine tune the suspension IMHO, and I mean FINE

[mdtoney]

I've read that the most important fluid change is after the first 500 miles, since the fluid from the factory is usually crap. After reading through numerous forums, it seems most guys go every other year.
A suspension shop recommended every 5,000 miles or every 2-3 years.

I change the fork fluid on my dirt bikes once a year. I haven't done it yet on the 919 so I'm hoping to get to it in the next month or two.

[zaq123]

I think they recommend 15-20 rides for dirt

[mdtoney]

I think that's about right for dirt bikes - that same suspension shop said 30-50 hours or every season. My ride time is really close to that number so I just change them over the winter every year. The wife's dirt bike is ready for spring (oil change, fork rebuild, clean and lube all pivots and bearings), mine is ready except for the fork fluid. After the dirt bikes, the 919 will get the same treatment.

[g00gl3it]

Wowza, I've NEVER changed the fluid on my dirt bikes. EEK. Better do it.

[mcromo44]

Originally Posted by rickard919

I ran my OEM oil for about 80k miles with no problems. Your call.

If anyone has ever questioned whether the 919 fork seals are too good, the above post says it all.
Over 80,000 miles on the original forks, never even cracked open until rickard let me at them for a wee peek inside the top.
All year riding, left outside, normal cleanliness.
The oil still looked like oil, had some discolouration, but you could see flecks floating about.
And the tubes are still desert dry !
No wonder the 919 front end has as much stiction as it does.

[nd4spdbh]

Originally Posted by g00gl3it

Wowza, I've NEVER changed the fluid on my dirt bikes. EEK. Better do it.

its night and day difference especially on dual chamber forks of your fancy race dirtbikes like the crf250's yz250f's etc.

also i think you guys mean NO LESS than 140mm of height (lower fluid amount by volume) and no more than 125mm of fluid height (max amount of fluid height) as height of fluid is measured from the top of fluid to the top of the fork tube... less fluid height means more fluid.

I noticed a big difference when i added the extra 25mm of fluid... definitely a lot less dive at my weight of 160ish. any more weight tho... the stock springs would definitely be too soft.

[zaq123]

Originally Posted by nd4spdbh

its night and day difference especially on dual chamber forks of your fancy race dirtbikes like the crf250's yz250f's etc.

also i think you guys mean NO LESS than 140mm of height (lower fluid amount by volume) and no more than 125mm of fluid height (max amount of fluid height) as height of fluid is measured from the top of fluid to the top of the fork tube... less fluid height means more fluid.

I noticed a big difference when i added the extra 25mm of fluid... definitely a lot less dive at my weight of 160ish. any more weight tho... the stock springs would definitely be too soft.

yes, you are correct. Make sure springs are in when checking oil height.
You can make your own tool for setting the oil level if you don't want to buy one:
take a pen apart and mark your 120-125-130mm marks on it. Attach clear fuel hose to it and large food injector on the other side. Put oil in the forks, align pen mark with the top of fork tube and suck the oil out until you start sucking air