Bonneville America Forums Forums Technical Forums General Tech Fork Oil Change out question (Speedmaster)

The Triumph maintenance manual/shop manual gives the volume of oil needed per fork then gives directions on removing oil down to a specified level.
Question: If I can accurately measure the volume (484 cc) they specify, do I need to do the other step(removal of oil down to the specified level (166 mm)?
Seems redundant to do both.
Thanks
Gary

Probably not.
But measure it anyway.

I'd say you should be ok with only the measurement unless you are changing spring (brands).

The most important measurement of fork oil is the oil height in the tube...actual replacement volume can vary depending upon how much of the old oil you removed.

Thanks to all for your replies and I'll do my best at the distance measuring after laboratory calibrated cylinder volume measurement and see how they compare. I have all stock parts so should be the same as T shop manual specs.

Post your results Gary.
It'll be interesting to see.

2005 Triumph Speedmaster
Fork Oil change Out Dec 28, 2008 - Miles 28,807.4 (4000 miles over recommended miles and one year beyond 2 year time) I was starting to feel some shock action that I hadn't felt before, just not smooth (I ride almost daily).
Procedure per Triumph Shop Manual - loosened only fork tube cap - removed fork tubes (after removing brakes, wheel & tire assembly, fender w/bracket), removed shock cap(careful has spring pressure so hold on) removed spacer, washer, and spring, poured out old oil into 500 ml water bottle (each fork)

Reference 1 cc = to 1 ml
Measuring device 500 ml graduated cylinder and 50 ml grad cyl
Oil removed per fork approx. due to oil remaining on parts = ~ 480 ml/cc

Owner manual spec. 10 weight oil used Bel-Ray 10w fork oil (comes in 1000-cc/ml container) from dealer.

Specifications (America and Speedmaster only) for fork oil volume and measurement as measured from top of fork tube to top of liquid level with fork completely compressed with spring washer and spacer removed after pumping shock a few times and letting sit to stabilize

Volume 484 cc/ml of Oil Measurement 166 mm

OK - the following is my experience - I measured 485 ml/cc of oil (assumed some would be stuck to walls of container and lost) and poured (until drip dry) into empty fork tube - I pumped the shock a few times and let sit 10 minutes. With the fork clamped in a soft jaw vise, I measured the fluid level (top of tube to top of liquid level with fork completely depressed ( no spring,washer or spacer installed yet)
The measurement was 200 mm ( spec called for 166 mm)
I kept filling until the 166 mm spec was met which totaled a 518 ml/cc of oil.

This is definitely more oil than I took out so I suspect that the measuring distance is not correct but 34mm(??). Anyway, I double checked everything including doing the second fork and it came out the same except for filling beyond the 484 ml/cc amount. I simple figured how much oil each mm of fork tube distance it would be to go to 166 mm and it came out to the same as the first one (each 1mm of fork distance equaled 2-cc/ml of oil).

Does anyone have reference to a different measurement? maybe the reference from the Haynes manual?

I guess I will remove some of the oil to bring it back to 484 ml/cc and try that as I'm afraid if I leave the 518 ml/cc in it (166mm measurement) that I will blow the fork seal.
Comments or help anyone?
Thanks in Advance,
Gary

From the Tech Vault:

Fork oil change

Looks like the Triumph manual may have been printed by Lucas.

Oh, and 19 oz. is 582 cc.

I called the service department at my T dealer today(closed on Mondays) and they said I should put back the same amount of oil I removed. As it turned out, I did pour the forks out into separate containers and for one of them I was was very careful to use a funnel to collect all the old oil even what I pumped out. This all measured out to be a little over 480 cc's. I think the remaining 4 cc's was stuck to the parts and inside the fork tube. I let them drain upside down over night.
I guess I should have measured the level before draining but I didn't.
After 28,807 mles (3yrs 5 months) the old oil was very dirty and had what looked like a black sludge when the last little bit was draining out. The same black stuff covered the spring, washer and spacer. I wiped everything I could reach with a lint free cloth. I measured 485 cc's (assumed 1 cc would stick inside the container) of fresh Bel Ray 10w fork oil and poured same into each fork tube.
For the heck of it I measured the liquid level again and it was 199-200 mm top of tube to top of liquid, fully compressed.
Got it all back together this evening and went for a ride and it feels perfect, much like i remember it being before the last few thousand miles when it started to feel uneven.
So, i can't explain the 200 mm measurement as apposed to stock 166 mm spec but I'm happy. I weigh 210 pounds and ride hard so as soon as my new front tire is broken in I will push it a little harder and see if it still feels right.
Gary

Just to add to this. My 2007 America had a service around four months ago and fork oil changed so not sure what original "Factory" level was. I decided to go to Progressive springs and I did the job myself.

I drained 530ml of oil and after letting the fork hang a few hours another 30ml of oil drained out so total quantity in the fork was 560ml. Given those numbers, I filled the fork with 600ml. Using a (Progressive Suspension) copy of the Triumph level adjustment tool I set it at 166mm and drained approx 40ml so that means I used 560ml which is exactly what I drained out.

Both forks were the same within 5ml.

It appears there is definitly a difference between the quantity and the height level spec in the Service Manual.

Not sure which one is correct but I will ask Triumph next week. The more accurate measurement is the height level as this takes into account any residual oil in the forks.

Fyi according to my Hagon rep, the bigger the air gap the softer the suspension, and btw Hagon suggests a 140mm air gap with their progressive fork springs.

Something else he advised (btw he actually worked in the Hagon factory as he knew the family) was to use half a cup of unleaded fuel in the disassembled fork (spring out etc) and carefully pump it up and down to get rid of any remaining residue.

Then upturn the fork for a fair while to ensure no fuel remained (it evaporates).

I did question him properly on this one and given his credentials and racing/mechanical experience I took his advice.

BTW, It did remove a dark gunky fluid which makes sense to me may build up over time, and considering we are talking about clean fork oil and obviously with it clean internal parts, I just thought this may be of interest to someone.

ride safe

When I installed the Progressive springs, I was able to suck 460cc of fluid out, so that is how much new oil I poured back in. Seems to work fine.
The stuff tastes awful, by the way. just kidding.

Hello!
I hope my experiance could help shed som light on this issue; In my Triumph manual it states in the General Information in the begining of the manual that both T100 and America has a front fork volume of 484 (x2). BUT in the adjustment chapter the volumes are specified different! 484 for the T100 and 584 for the America. And this volume was confirmed when I changed recently. I used a little bit more than 1000 for my both fork legs to achive 166 mm oil level hight.
Regards
Hasse

Why is there such a large difference in the volume of oil reported in the two posts above? Something to do with how the oil was removed?

Well, in my case I emptied one leg at the time, upside down and pumping the oil out and then let the remaining drain out for a while. Did not measure the volume of the old oil. Filled it up to specifications and is left with about 0,85 L of oil remaining in the second bottle.

Fork oil amouns vary for several reasons. Some guys have changed springs and thus changed the amount of oil needed,in other cases such as this it's how the oil was removed. You will never get all the oil and gunk out with a suction gun. IMO to do the job right on our forks you really have to pull them and flush them out, on the old forks there was a drain at the bottom you could flush the old oil and gunk out of and then replace the plug and fill. That way no real need to pull the fork legs.

Through Progressive I just got a tool that I carry it on my site now because it is VERY useful. Simple in construction and well made. A measuring end where you adjust the oil level then draw off the exact amount, no guessing or re-do's. Have done it both ways..this is a very effective tool. The clever can maybe make this on their own.

In the old days with Trials Bikes we used to use a coat hanger wire and mark the level, but if you over filled it was a pain to draw off and get it just so.

Fork Oil Leveler

eddy