When to service your Forks

[Satterfield]

I am about to have the fork oil changed on my 2008 K9, they were rebuilt last 7k miles ago. I noticed the other day after a ride that I had some black marks on the area 2" above (on the uppers) the lower tubes (not oil) So should changing the oil be enough or is another rebuild in order. Inside the caps is dry and no leaks are evident. However, it seems the legs are showing a little wear. I assume that a certain amount of wear marks are normal, (I have had the bike since new in 2010). That being true new upper legs is the only way truly back to normal. My concern was that this seemed to appear after a single ride (it had been sitting for almost a year-likely not relevant)

I apologize for posting this way but I could not seem to find a specific answer. I don't do the work on my bike I only ride it and I am not adept at posting here nor working on my bike, so it cost me a lot of money. I am going to hope for an answer anyway. This is a great site with great people. I will spend some time educating myself on protocol after I get past this.

Any comments are appreciated, Thanks in advance. Tony

 

[TapioK]

I am about to have the fork oil changed on my 2008 K9, they were rebuilt last 7k miles ago. I noticed the other day after a ride that I had some black marks on the area 2" above (on the uppers) the lower tubes (not oil) So should changing the oil be enough or is another rebuild in order. Inside the caps is dry and no leaks are evident. However, it seems the legs are showing a little wear. I assume that a certain amount of wear marks are normal, (I have had the bike since new in 2010). That being true new upper legs is the only way truly back to normal. My concern was that this seemed to appear after a single ride (it had been sitting for almost a year-likely not relevant)

I apologize for posting this way but I could not seem to find a specific answer. I don't do the work on my bike I only ride it and I am not adept at posting here nor working on my bike, so it cost me a lot of money. I am going to hope for an answer anyway. This is a great site with great people. I will spend some time educating myself on protocol after I get past this.

Any comments are appreciated, Thanks in advance. Tony

"Black marks" do you mean dirt or the chrome shows wear marks?
Picture might help... there will be some dust and water creeping down the tubes in to the caps causing some dirt marks appear on tubes when forks are pressed down? If that is the case just screw the caps open and clean underneath. You mentioned the marks are not oily...

 

[TapioK]

Oh, I noticed on the other thread you said the mark is burned or was it etched into tube. Sounds like the copper shows thru the chrome? That would mean the chrome is wearing thin? Nothing you can do about that, except to replace the tubes I suppose. We need a pictures... why that happens? The tube is not exactly round? Tube is Just slightly bent? The bush and oil seal are slightly worn and let dust+oil between tube and seal. That rubbing paste eats thru the chrome fast...

 

[blacktopper]

"Black marks" do you mean dirt or the chrome shows wear marks?
Picture might help... there will be some dust and water creeping down the tubes in to the caps causing some dirt marks appear on tubes when forks are pressed down? If that is the case just screw the caps open and clean underneath. You mentioned the marks are not oily...

I have an 07 K9 with over 80,000 miles and have never touched the forks. I think it should go a long time before you have to do anything.

 

[Nukeranger]

I looked in the Big Dog Service Manual and it is recommended to replace the Fork Oil every 10,000 miles. I currently have around 16,000 miles and plan to service my forks after the Kansas trip which will include changing the oil, seals, etc.

 

[BWG56]

I looked in the Big Dog Service Manual and it is recommended to replace the Fork Oil every 10,000 miles. I currently have around 16,000 miles and plan to service my forks after the Kansas trip which will include changing the oil, seals, etc.

Wait until ya smell that oil, man does it stink. I changed my fork oil around 15K when I put a tire on the front, I just pulled the plugs at the bottom of the forks, left it drain, add some more oil and worked the forks and drained it again before refilling. You can use Screaming Eagle heavy fork oil to refill. I had no signs of wear on the tubes yet.

 

[woodbutcher]

the manual calls for 10k, that being said, the first time i changed mine was at 8.5k and it was time. the way they ae made, they are steel, lined with brass/bronze, lined with teflon which is what keeps the tubes from binding and getting scratched. at 8.5k, the teflon was practically worn through and ready to start on the brass/bronze, which would be worse on the tubes than the teflon but not near as bad as the steel. as far out as the fork is extended, it is obvious there are only two points that take all the beating and that is directly where the bushings are located.

blacktopper, i am amazed that you have 80k on your forks!!!

 

[blacktopper]

the manual calls for 10k, that being said, the first time i changed mine was at 8.5k and it was time. the way they ae made, they are steel, lined with brass/bronze, lined with teflon which is what keeps the tubes from binding and getting scratched. at 8.5k, the teflon was practically worn through and ready to start on the brass/bronze, which would be worse on the tubes than the teflon but not near as bad as the steel. as far out as the fork is extended, it is obvious there are only two points that take all the beating and that is directly where the bushings are located.

blacktopper, i am amazed that you have 80k on your forks!!!

For some reason I don't like messing with those things so I just left them alone. I bought a rebuild kit from Curtis about 3 years ago and never used it. Thought I would rebuild them if they ever started leaking. No sighns of a leak yet so I'm running them till they do

 

[BWG56]

Can you imagine what Blacktoppers is like after 80 some thousand miles....

Its called sludge

 

[BWG56]

That's very clean looking

 

[TapioK]

It does look like chrome is wearing out? What comes to parts, I thought pretty much all the parts are available from Donna & Derek or from Big Dog

 

[Th3InfamousI]

Thank you all very much for your replies. It seems that I should change the oil (even though there is no evidence of any leakage). We removed the caps and it all looks very dry and noting out of the ordinary. It seems that I am just finally seeing the wear on the forks form it 10k miles so far. While it is only a small place (this burned in black mark) that you can see now. But its definitely burned in (cannot be cleaned off) and I guess the other side is going to do the same. I clean it every time I am finished riding now for 7 years, that is how I know it just appeared one day and not over time. I don't want to have them rebuilt unless I must its been barley 7k since a full rebuild when I had the lowers re chromed after an accident. I don't have and don't see in my shop many Big Dogs to compare it too. (I am just north of Tampa). I am a bit retentive when it comes to keeping my bike spotless so watching it continue to get worse just does not appeal to me at all.

I included a couple of photos here although it does not show up in a photo very well. Its to bad so few parts are now available and it does not look like BDM does very little in the way of parts. Also it is only on one leg so far.

Thanks again for your comments, this site is an incredible resource, I joined seven years ago and its only grown more vibrant thanks to its many members who stand ready to help others.

I know what your talking about...its wearing abit but nothing to worry about.

I have the same issue on my 07. I'll probably run the tubes for a while before I replace really it won't hurt anything.

Keep riding Sir...maybe next time you have the fork seals done have the shop replace the tubes too they are not super expensive.

When it wears enough the seals will start leaking, then you know you gotta replace

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[Mickeetwo]

I didn't change my seals and oil until 30,000 miles. I had some wear on the upper fork tube, but no leaks. When I installed the forks I turned the tubes 180 degrees in the trees. Still no leaks. Most of the wear on the tubes will be on the front side

 

[Th3InfamousI]

Thank you very much for your reply, this does mean changing my fork oil now is a good idea or needed? If you are having the lower legs rebuilt how much more labor to do the upper forks. The forks is you can find them are not that expensive (about 300.00 I would guess) but the labor is the costly part of it when you cannot do it yourself (not only lacking the technical skill but also physical reasons prevent me from even trying). So I am weighing my options.

Shouldn't cost anymore labor to replace the tubes next time you get the seals changed as they have to take it apart anyways.

You can change the oil at any time that won't hurt nor will it help your issue. So that is up to you. Ride it for the rest of the season and this winter you can put it in the shop for new tubes and seals.

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[Th3InfamousI]

Thanks again, if it will not help the issue then as you say the logical thing I guess is better to spend that money on getting the new forks for installation as you say after putting a few more miles on these. The quote for the labor for removal/replacement when asked for a "ballpark" estimate was 250.00 then I am guessing another 400-500.00 in parts for the both then tubes and the rest.

I have even more problems which is after the fluid change during service, primary/oil the shifting got rougher and finding neutral became an art. So he adjusted it.. and now its even worse. You can't even get it into neutral while at idle and difficult to down shift to when preparing to stop (like a red light). Previous to the service neutral was no problem at all. Thank you again.

Regarding the neutral issue...make sure he doesn't use synthetic primary fluid. The new Harleys like the synthetic stuff but these bikes hate it.

Just regular Primary oil or ATF Type F fluid. No synthetic.

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[TapioK]

Thanks again, if it will not help the issue then as you say the logical thing I guess is better to spend that money on getting the new forks for installation as you say after putting a few more miles on these. The quote for the labor for removal/replacement when asked for a "ballpark" estimate was 250.00 then I am guessing another 400-500.00 in parts for the both then tubes and the rest.

I have even more problems which is after the fluid change during service, primary/oil the shifting got rougher and finding neutral became an art. So he adjusted it.. and now its even worse. You can't even get it into neutral while at idle and difficult to down shift to when preparing to stop (like a red light). Previous to the service neutral was no problem at all. Thank you again.

sounds like they put wrong oil in to primary or tranny. tell them NEVER synthetic oil in primary. I wonder what oil he used. Does the clutch slip?

 

[Th3InfamousI]

No the clutch does not slip as far as I can tell. They did not change the transmission fluid only primary and oil. The primary was BEL-RAY 1 LTR according to the invoice. Thank you!

I don't know much about BelRay primary fluid...but a quick Google Search led me to a Harley Forum and said he spoke to BelRay and received the below response


"The Bel-Ray Gear Saver Transmission Oil 80W is the exact same oil as the Bel-Ray Primary Chain Case Lubricant. This oil does not contain any additives that will react with yellow metals in your motorcycle."



Doesnt appear to be synthetic but 80w might be a bit too thick for you. These big dog clutches are a bit less forgiving than Harley's.

When he goes to adjust your clutch make sure he only backs it off 1/4 turn! As that is BDM spec for these. Standard Harley's recommend a 1/2 to a full turn which won't work for you. Mechanic may be unaware of backing it off only a 1/4 rather than 1/2.

Run by auto zone and pick up a quart of B&M TrickShift for $10 and ask your mechanic to put that in the primary for you. I'd recommend just draining it and doing it yourself but that doesn't seem like a task your willing to try. But would save you some bucks.

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[TapioK]

Anyone near Tampa to give the bike a quick look?

 

[LUPHOLE]

my k-9 has thirty some thousand miles on it and I changed out the fork seals and bushings this past winter. the old bushings did show some ware and I was glad I did it (hauling my fat ass around is hard on everything). the kit from Curtis has everything you need including the fork oil---well worth the money. i was surprised at the amount of crud that i cleaned from all of the parts when disassembled. when I put the forks back together i did rotate the tubes ninety degrees to adjust to a new heavy contact surface. also,the drawing in the service manual was not exactly what I found when I took it all apart but it was not a major problem. it took a lot of time but really, even with my limited talent, it can be done. next time, it should go much quicker. I do notice some discoloring of the tubes just above the fork legs but most just wipes off.
if the bike gets wet, I always unscrew the cap on the legs and blow out any water that seeps in.
I had changed the fork oil twice before and each time it was nasty (blacktopper, yours should go right into the paver when you get around to draining it (just kidding)
anyhow, i have been using the revtec primary oil on the advice of my local mechanic. nothing fancy and so far so good.
i love my dog!!!

 

[Satterfield]

I don't know much about BelRay primary fluid...but a quick Google Search led me to a Harley Forum and said he spoke to BelRay and received the below response


"The Bel-Ray Gear Saver Transmission Oil 80W is the exact same oil as the Bel-Ray Primary Chain Case Lubricant. This oil does not contain any additives that will react with yellow metals in your motorcycle."



Doesnt appear to be synthetic but 80w might be a bit too thick for you. These big dog clutches are a bit less forgiving than Harley's.

When he goes to adjust your clutch make sure he only backs it off 1/4 turn! As that is BDM spec for these. Standard Harley's recommend a 1/2 to a full turn which won't work for you. Mechanic may be unaware of backing it off only a 1/4 rather than 1/2.

Run by auto zone and pick up a quart of B&M TrickShift for $10 and ask your mechanic to put that in the primary for you. I'd recommend just draining it and doing it yourself but that doesn't seem like a task your willing to try. But would save you some bucks.

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[/QUOTE]

Thank you, I will try that. He just made a quick adjustment of the cable I think and it got worse as I think I said I can't get neutral from idle anymore and over all things seem to be clunky.