Knocking noise in forks after oil change?

[DonHo]

Hello, I decided to service my forks in my recently acquired  1973 Eldorado.  I measured the oil volume that came out and it was approx. 4 oz each side.  (It looked and smelled like ATF).  After reading the info on Gregory Benders site (love that site) I decided to put in 8oz of 30 wt fork oil.

After this I noticed a loud CLUNK noise when hitting certain bumps (like pulling in a parking lot from the street at moderate speed). Simply compressing and releasing the forks produce no sound.  I never noticed this before changing the oil. I have read in several places that people have success with this oil weight/volume combination, but wonder if others may have experienced what I have.  (I Hate to tear down the forks if not necessary)

Thanks for any tips!!

Don

[John A]

How old are the fork springs ?  If they are the originals they are sagged out. If they clunk on the up stop they maybe need a heavier oil.  I've been using regular motor oil, the forks can't tell.

[LowRyter]

did you take 4oz out and put 8 back in?

[Antietam Classic Cycle]

8oz of 30 wt fork oil is what I use in my Loops and those of my customers as well. No matter how much (within reason) of whatever oil you put in the drum-brake forks, with original springs, you'll get some clunking - either topping out or bottoming. New Wirth progressive springs along with 8oz of 30 wt fork oil has drastically reduced that on my V700. Being a heavier oil, it may take a while to work into all the recesses of the forks, so maybe give it a bit more time.

did you take 4oz out and put 8 back in?

Factory spec. is 5.6 oz. (rounded to 6). 4 oz. is a bit too little.

[DonHo]

did you take 4oz out and put 8 back in?

Yes, 4oz (ATF I think) and installed 8oz 30wt fork oil.  I didn't notice the noise before I changed the oil.

[DonHo]

8oz of 30 wt fork oil is what I use in my Loops and those of my customers as well. No matter how much (within reason) of whatever oil you put in the drum-brake forks, with original springs, you'll get some clunking - either topping out or bottoming. New Wirth progressive springs along with 8oz of 30 wt fork oil has drastically reduced that on my V700. Being a heavier oil, it may take a while to work into all the recesses of the forks, so maybe give it a bit more time.
 

Factory spec. is 5.6 oz. (rounded to 6). 4 oz. is a bit too little.

Thanks so much for the advice.  I think I will ride it a bit more to see if the noise calms down.  Do you sell those wirth progressive springs?

[Antietam Classic Cycle]

Thanks so much for the advice.  I think I will ride it a bit more to see if the noise calms down.  Do you sell those wirth progressive springs?

No, bought them from MG Cycle: http://www.mgcycle.com/index.php?main_page=product_info&cPath=197_199&products_id=1147

[Chuck in Indiana]

Yes, 4oz (ATF I think) and installed 8oz 30wt fork oil.  I didn't notice the noise before I changed the oil.

The mind is a funny thing. Maybe it's been doing it all along? Maybe you are listening for it because you serviced it? The Loop front end is *not* terribly sophisticated..

[DonHo]

The mind is a funny thing. Maybe it's been doing it all along? Maybe you are listening for it because you serviced it? The Loop front end is *not* terribly sophisticated..

Its a pretty evil noise.  I had ridden it about 1500 miles before servicing.  I'm sure I would have noticed it.  (I wouldn't ride it much at all making this noise)

[Chuck in Indiana]

Its a pretty evil noise.  I had ridden it about 1500 miles before servicing.  I'm sure I would have noticed it.  (I wouldn't ride it much at all making this noise)

Well, it's pretty obvious you'll have to have them apart and have a look. Maybe you left a wrench in there..  

[Cam3512]

Is anything hitting your front fender when forks are compressed?

[Sprouty115]

Its a pretty evil noise.  I had ridden it about 1500 miles before servicing.  I'm sure I would have noticed it.  (I wouldn't ride it much at all making this noise)

I relazie this is s pretty old thread, but since I have the same thing going on with my new-to-me '73 Eldorado, I figured I'd ask if changing the springs and oil solved the issue? 

I have the springs in the cart at MG Cycle ready to pull the trigger...

[Antietam Classic Cycle]

I relazie this is s pretty old thread, but since I have the same thing going on with my new-to-me '73 Eldorado, I figured I'd ask if changing the springs and oil solved the issue? 

I have the springs in the cart at MG Cycle ready to pull the trigger...

The original springs are likely sacked out, new springs will certainly help. First though, try increasing the amount of oil in the forks from the original 5.4 oz. to 8 oz. I use 30w fork oil.

[Sprouty115]

The original springs are likely sacked out, new springs will certainly help. First though, try increasing the amount of oil in the forks from the original 5.4 oz. to 8 oz. I use 30w fork oil.

Ah good idea.   I'll give it a try before I spend any more money..

[guzziart]

I have the springs in the cart at MG Cycle ready to pull the trigger...

Last year MG Cycle also offered Stucci progressively wound springs for a little less than the Wirth but I now see they are not offering them these days.  New springs made a huge difference in the front end ride quality on my '72 Eldo.  I'm now looking to get off my wallet for rear shocks.  Good luck!
Art

[bigbikerrick]

Its been some years sine I rebuilt the forks on my eldorado, but I remember needing 10 oz of oil in each leg, and I ended up using some straight 50 wt "harley" oil in my forks. 9 oz would cause the damping to be irregular. I kept adding oil, and working the fork through its travel, until I found the amt. that worked evenly through the full stroke. In my case it was 10oz.  My front end would "clunk" when hitting a chuck hole, or other pavement irregularity, with thinner oil, or less quantity of oil. I hope it helps,
Rick.

[Sprouty115]

I ended up pulling the tank off to re-orient the petcocks, and that led to ordering new fuel line, which I'm now waiting to be delivered.  Once that's all sorted I will get back to the forks.  Hopefully this weekend - it sounds like I have a few options to try before spending money on springs.

[Fontain25]

Was also interested in this thread. Same thing happened to me. After oil change with 8oz of 30wt fork oil I developed a knock. Recently changed to Wirth fork springs and problem is solved.

[Sprouty115]

Just a quick follow-up from my earlier post - I drained the oil in the forks and replaced it with 8oz of 30wt.  It "helped" but it's still not acceptable.  So now that it's winter, I'll be ordering the springs recmmended above and fitting those.  Will post again after that is done and I have a chance to evaluate it...

[guzziart]

Just a quick follow-up from my earlier post - I drained the oil in the forks and replaced it with 8oz of 30wt.  It "helped" but it's still not acceptable.  So now that it's winter, I'll be ordering the springs recmmended above and fitting those.  Will post again after that is done and I have a chance to evaluate it...

It probably couldn't be the center stand banging around down there because the stop is bent or MIA.
 

[Sprouty115]

It probably couldn't be the center stand banging around down there because the stop is bent or MIA.

It sure sounds like the forks, but it's a good suggestion and easy enough to zip-tie the centerstand up. Thanks.

[guzziart]

FWIW, Since my reply #14 from Nov 23, I have purchased Ikon shocks for my Eldo last spring.  Just like the Stucci front springs I installed that were reasonably inexpensive, the Ikons are another great improvement for me.  I hated spending the money but after the first ride with the new Ikon Dial A Ride shocks I had absolutely zero buyers remorse. 

[Offcamber1]

It has been 30 years since I owned a loop, but when I restored my 70 Ambo Denny Laidig in Akron rebuilt the front forks and he suggested using 40 weight Harley fork oil.  I believe he mentioned doubling the amount, so I would second BigBikeRick's comment.

Made a huge difference; as I recall it was like a completely different bike.

Kip

[Fontain25]

Its been some years sine I rebuilt the forks on my eldorado, but I remember needing 10 oz of oil in each leg, and I ended up using some straight 50 wt "harley" oil in my forks. 9 oz would cause the damping to be irregular. I kept adding oil, and working the fork through its travel, until I found the amt. that worked evenly through the full stroke. In my case it was 10oz.  My front end would "clunk" when hitting a chuck hole, or other pavement irregularity, with thinner oil, or less quantity of oil. I hope it helps,
Rick.

Hello , pleased to meet you. No doubt you are a big biker but just how big? Asking just for perspective - don't mean to be personal.