Handling Fork oil....again

Mr B

Mr B

Registered User
Sorry about this, but I've done a search and checked my factory manual and can't find the answer.

What weight is the oil in my 2003 RKC front forks as installed at the factory.

I want to go a bit thicker and I'm not sure what the factory put in to start with.

After banging a big dent in my front mudguard, I checked to see just how high the mudguard came up. Where I put my horn, it was so high up (see my other thread), that for the mudguard to hit it must mean that the forks bottomed out....and easily.

There's no leaks, and I've never taken any oil out, so what's in there is what the factory put in, and it's clearly inadequate. Any ideas how much I'll notice it if I go up a grade or two. What grade oil do you use on your RK front end and are happy with it.

I ride solo most of the time and I don't hit bumps on purpose, but I has to be stiffened up a bit......the guard almost touches the top of the down tubes without much effort when you put the brake on hard. (I had someone stand at the roadside and I did a full on front brake at 30 mph when I was level with them). I did notice a long time ago that everytime I've taken it up to or above 90mph that the bike is nodding it's head quite badly at that speed, which would indicate bad damping. I just got used to that, and I ignored it until now.

Brian.
 
Re: Fork oil....again

LOL....Brian what did you search for? I put in fork oil weights... :439:

HD type E has worked well for 72 k changed twice. Should be every 20k :redface:

amount 328cc. Try a couple of extra cc's.

Doesn't say on the H-D bottle what weight it is but chopper has gone up to 20w on his FLHR

http://www.harley-davidson-hangout.com/forum/hdrcgb-evo-big-twins/97948-fork-oil-flhs.html

http://www.harley-davidson-hangout.com/forum/hdrcgb-twin-cam-tc88-tc96/90234-fork-oil-weights.html

http://www.harley-davidson-hangout....g-twins/65299-better-damping-front-forks.html
 
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Re: Fork oil....again

I pretty sure 15w is stock, i went with 20w before i did the cartridge inserts this winter and it was better IMO
 
Re: Fork oil....again

I would think your oil is well past it's sell by date now.
You can't even be sure you had the correct amount in there from new.
If your manual specs 99884-80 type E,there is a SE Heavy Duty version 99881-87.

It's meant for racing,so mind how you go.:D
 
Re: Fork oil....again

Fork Oil - 16oz. Type E 5wt. Type E is for "Showa" forks.Part # 99884-80

Fork Oil - 16oz. Type B 10w. Fork Oil - See owners manual for recommended style. Part # 99880-73

Screamin? Eagle? Performance Fork Oil - A heavier oil (15wt) provides extra damping in performance application. Part # 99881-87 . Works well to take the dive out of the front end on breaking.

Screamin? Eagle? Racing Fork Oil - Designed and blended for the severe conditions on the race track (20wt). Not intended for street use.
Part # 99909-93R
 
Re: Fork oil....again

If its any help I had standard 10wt fork oil in my nightrain forks and changed to the Squacky Pigeon performance stuff which is 15wt. and as Baff said it works better and reduces front end dive under heavy breaking

If that aint enough you can add a wee bit extra cc's
 
Re: Fork oil....again

Since I upgraded my fork oil last week, my horn hasn't touched my mudguard once. :wink:
 
Re: Fork oil....again. UPDATE

Re: Fork oil....again. UPDATE

An Update

I drained the oil from both legs. There is supposed to be 328ml in each leg. I carefully measured what I got out, and in the left leg, I got 130ml out. In the right leg, I got less than 50ml.

I began to wonder if there was oil trapped inside that hadn't run out, so out came the fork legs, and I left them draining upside down all night. Just black silvery oil was all that was in there.

I flushed the legs through with new oil, drained them again and refitted them to the bike. Then put in 330ml of synthetic 15 weight fork oil in each leg. It's all back together now, but I've developed a clonking noise from one of the legs when I bounce it with the brake on. It hasn't been road tested because it's pissing down here today. It certainly feels firmer on the front end now.

So, it looks like next Winter, it's going to have a fork upgrade, probably Progressive cartridges.....is there ever an end to this upgrading the inferior parts that they fit at the factory...and where is quality control.

Whoever originally put the oil in my forks at the factory just didn't give a shit.

The bikes done less than 8,000 from new and never had a leak, so it's obvious the oil was never put in to begin with.

Brian.
 
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Re: Fork oil....again

Limey_Dave said:
I would think your oil is well past it's sell by date now.
You can't even be sure you had the correct amount in there from new.
If your manual specs 99884-80 type E,there is a SE Heavy Duty version 99881-87.

It's meant for racing,so mind how you go.:D
Click to expand...

I rest my case.:wink:

As to the clonking,if it's doing it now,and it wasn't before,something has changed since you had it apart.
I'd check that everything was setled and aligned before it was tightened up,and that it's a fork clonk,not a caliper clonk.
 
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Re: Fork oil....again

Limey_Dave said:
I rest my case.:wink:

As to the clonking,if it's doing it now,and it wasn't before,something has changed since you had it apart.
I'd check that everything was setled and aligned before it was tightened up,and that it's a fork clonk,not a caliper clonk.

238-330 ml is a big jump.
Click to expand...

Dave, I made a typing error, which has been corrected now. It should have 328ml in each leg. I've put 330ml in each leg.

The clonk was a caliper knocking as you suggested....cheers mate. A suspension upgrade is still on the cards though. That black silvery oil will always be in my mind now. I'll never get round to upgrading the engine at this rate :wink:. I suppose safety has to come first before more hp.

Brian.
 
Re: Fork oil....again

Glad it's sorted Brian,and now we go our seperate ways.
I may replace my forks one day,but not till I've worn these ones out.:)
 
Re: Fork oil....again. UPDATE

Re: Fork oil....again. UPDATE

Mr B said:
An Update

So, it looks like next Winter, it's going to have a fork upgrade, probably Progressive cartridges.....is there ever an end to this upgrading the inferior parts that they fit at the factory...and where is quality control.

Brian.
Click to expand...

Highly recommend them Brian, I was never very happy with the front end on mine even after changing to 2006 legs and brakes and heavier oil, i tried three different weights, then bought the cartridge inserts after a bit of research late last year and put them in my RK this winter and so far i have nothing but good praise for them, I bought the lowered version which allows 1 or inches of drop, ive gone down 2", and the bike now has a very responsive front end, almost non existent brake dive with decent re-bound and proper damping! the small amount of 5w fork oil the forks now have in them is used for lube only!
 
Re: Fork oil....again

UPDATE

Thanks to everyone who gave advice on this, and especially my mate Baff.

I've been out on it today for the first time since I put 15W fork oil in.....what a difference. The front end feels very firm on the road. I'm well pleased with it. No bouncing at all, and very positive steering. My new front floating discs work well too.

I might not upgrade to fork cartridges now....it feels better than I've ever known it....we'll see how I feel later on.

The bike has developed a slight misfire sometimes....not all the time, at low speed. This might be due to it being left for 6 months without any use. Maybe I just need to go out and wring it's neck to clear all the cobwebs out. Whatever it is, I'll find it and fix it.

Roll on all the things I've got planned for this year with Anglia and anyone else that'll have me. I'm like a kid with a new toy at the moment :D.

Brian.
 
Re: Fork oil....again

I put in stiffer single rate springs more appropriate for my weight and riding style along with some slightly modded Ricor Intiminators.
 
Re: Fork oil....again

I put in stiffer single rate springs more appropriate for my weight and riding style along with some slightly modded Ricor Intiminators
Click to expand...
Yup, I found that set up transformed the forks on my Sportster. My only caveat is that you don't need to mod the Intiminators if you use Silkolene pro RSF 2.5W oil. It has a similar viscosity to the recommended oil but double the VI and hence works much better in our colder climate.
 
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Re: Fork oil....again

Never been happy with the bouncy front end so mine were drained and 20w added.

Great cheap fix IMHO.
 
Re: Fork oil....again

I'll 10-4 that, Les049. I put Silkolene 20W in my 2001 Heritage front end and also adjusted the rear shocks up properly. I had always assumed that it was a Softail thing that made it as nimble as a rhino on roller skates. Truth is that when set up right Softails are ok, mine feels like a new bike now. However now I am pushing it a bit, I am starting to think about suspension upgrades to see what it can do.....Kill me probably haha
Dunno if it is still the same with new bikes but I am sure the previous owner of mine just left it on stock settings form new, just as I did at first
 
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