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Discussion Starter · #1 ·
Anyone know how much oil is in each leg (cc) or measurement from top of leg to oil (spring in or removed etc)?
 

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427cc in the right leg.
298 cc in the left leg.
Standard Oil - Shell Advance 7.5 Fork Oil

(As stated in handbook.)
 

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Discussion Starter · #3 ·
Ha! now there was a place I never thought to look, thanks Joe. 1st time I have seen a different level for each leg, wonder why?
 

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I've not studied it yet but the reason could be because one leg does rebound and the other takes care of compression. ie. the internals would be different.
I doubt very much if it's anything to do with the mount for the calliper, it's not hollow.
Years ago Honda used a valve triggered by the movement of the calliper to control diving under braking which changed the oil quantity slightly in each leg. It was a rubbish idea and soon dropped.
 

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I doubt very much if it's anything to do with the mount for the calliper, it's not hollow.
I realise it's not hollow, which is why I suspected it may have a reduced capacity compared with the right leg. I've read nothing of compression in one leg and rebound in the other. It was mainly Marzochhi forks that had that feature, but wasn't particularly successful. The fork leg without any compression damping tended to wear the bushes under hard use. I know of a few riders who had such forks replaced under warranty for persistent knocking noises from them.
 

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I realise it's not hollow, which is why I suspected it may have a reduced capacity compared with the right leg. I've read nothing of compression in one leg and rebound in the other. It was mainly Marzochhi forks that had that feature, but wasn't particularly successful. The fork leg without any compression damping tended to wear the bushes under hard use. I know of a few riders who had such forks replaced under warranty for persistent knocking noises from them.
"It was mainly Marzochhi forks that had that feature" ?

WP Suspension are doing it currently and are as good if not better than Ohlins. The theory being a fork with one thing to take cars of has an easier time and can do it's job without compromise. The spring does the preload.

"I realise it's not hollow, which is why I suspected it may have a reduced capacity compared with the right leg" ?

Why would the calliper mount affect the oil capacity if it was solid ? Especially if the other side has no mount.
The other question I would ask is, Why would a fork leg without compression damping wear bushes ?
There would be no need to write about it in the manual etc. as they're not adjustable anyway.

You did say your guess would be...
All I did was disagree with you guess and offer a more plausible technical explanation. No need to start flexing your muscles and trying to prove your technical prowess with guesses.
 

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Oooh, you sound a bit sensitive, I thought skin was a bit thicker north of the border. :) You've clearly taken offence where none was intended, so apologies.

To take your points though -

Why would the calliper mount affect the oil capacity if it was solid ? Especially if the other side has no mount.

As the only external visible difference is the caliper mount, it would be reasonable and plausible to suggest that the mounting, solid or hollow has in some way affected the capacity. It may not be correct, but it is reasonable and plausible to suggest it. I presented it as a guess, as I simply didn't know.

All I did was disagree with you guess and offer a more plausible technical explanation.

My comment was that I had seen no reference to having compression and rebound damping in any test, any website or the handbook. So your suggestion is as reasonable and plausible as mine, because neither of us have anything concrete to back it up.

"It was mainly Marzochhi forks that had that feature" ?

The first bike I owned that had rebound and compression damping in each leg was a Moto Guzzi V11 Sport, and they made a fuss about it at the time as it was a new feature for them. They quietly dropped it on later 1200 Sport models, though the forks were still made by Marzochhi.

The next bike I was aware of having Marzochhi with this feature was the BMW HP2 Enduro. A search on UKGS'er will find pages of discussion about knocking forks, with some even going to the expense of converting to WP forks after struggling with post warranty claims. When BMW then launched the HP2 Megamoto, it retained Marzochhi forks, but went back to conventional damping. I've seen no reports of any Megamoto having problems, and I'm on my second Megamoto, so do keep up with the HP2 forums.

The other question I would ask is, Why would a fork leg without compression damping wear bushes ?

BMW were reluctant to deal with the problem and never admit there is a problem unless they have to. But, the theory was that when used hard the leg with just the rebound damping was taking the hit harder than the leg which had the additional support of compression damping absorbing some of the hit. It certainly seemed plausible to me.

WP Suspension are doing it currently and are as good if not better than Ohlins. The theory being a fork with one thing to take cars of has an easier time and can do it's job without compromise. The spring does the preload.

I wasn't aware WP were now doing this, and it will be interesting to see how it fares over time given that KTM are the parent company, and whose off roaders will certainly give it a tough time.

I've owned a few KT's and CCM's with WP and also had it aftermarket fitted to a couple of bikes and it's undoubtedly good. But, I wouldn't say it's as good as or better than the Ohlins equipped bikes I've owned. We've all got different expectations of suspension though so each to his own.

No need to start flexing your muscles and trying to prove your technical prowess with guesses.

As said at the start, no offence was / is intened. This is simply a discussion forum, and every guess (mine or yours) has some merit until corrected by the facts, which neither of us have at this point.
 

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Why would the calliper mount affect the oil capacity if it was solid ? Especially if the other side has no mount.
Joe, If you look at the construction of USD forks both legs are effectively 2 tubes containing the spring, damping components and some oil. The lower leg has a casting attached to the bottom of it, in the case of the Scrambler the casting on one side has a lug to mount the caliper and the other side doesn't but the tubes are the same. The presence or not of a lug to mount the caliper will have no bearing on the internal capacity. Any difference in the oil capacity of each leg will be due to the internal construction and function of the damping mechanism in each leg.
I haven't got my bike yet and I haven't seen a exploded diagram from a parts list as they still aren't available, so I'm not even going to hazard a guess as to why the capacity is different for each leg.
 

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Discussion Starter · #10 ·
When I had a test ride from my dealers demo bike I found the suspension (as most others have) a bit wanting on the damping side of things but the front was very soft to the point of diving way too much even when you touched the front brake.
I took a gamble and got the dealer to fit some heavier fork oil at the PDI before I picked my bike up. Personally I would have only went to 10w but they put in 15w which on something that is harshly damped initially was made a lot worse. That said, the dive had disappeared but my elbow joints were getting a battering on my local preferred roads.
Yesterday I made the decision to change the oil myself and put 7.5w Fuchs racing fork oil in and apart from knowing how much was in each leg (and looking at a few youtube vids on KYB forks) I had no idea what to expect inside.
LH leg 1st, was easy to drain and the spring on this side seems to be below the rod as I couldnt even see it. Got approx 295cc out of it and was happy there was no more in. Replaced it with 297ish cc or 10fl oz, put it back together then back on the bike no probs.
The RH leg is completely different and has a plastic spacer come spring guide that is approx 200mm long with the spring below it. You have to compress the spring with the spacer/guide to get to the nut underneath with a spanner to hold while you take off the fork cap. Once done you can remove the spacer/guide & spring.
Getting the 427cc out of this leg is some task pumping the rod in and out (I put the fork cap back on for something more substantial to hold onto) pumping the rod in and out then the outer part of the fork between times and slowly but surely I got just over 400cc but the damper was nice & free (ie just air inside).
filling the oil was less hard work putting some in then pumping until air purged & repeating until happy that around 425cc in & damping rod movement consistant, back together as it come apart then back on the bike.
Made sure everything tightened up and went out this morning down my local twisty bumpy road, ended up really happy as the harshness has lessened so now it is better than the demo bike, is more comfortable on my elbows but doesn't dive as initial test ride.
As I was unsure of what to find I had no thought of videos or photo's unfortunately but wasn't prepared to wait for exploded diagrams or torque settings (I went off previous jobs I did on my Tiger800).
 

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When I had a test ride from my dealers demo bike I found the suspension (as most others have) a bit wanting on the damping side of things but the front was very soft to the point of diving way too much even when you touched the front brake.
I took a gamble and got the dealer to fit some heavier fork oil at the PDI before I picked my bike up. Personally I would have only went to 10w but they put in 15w which on something that is harshly damped initially was made a lot worse. That said, the dive had disappeared but my elbow joints were getting a battering on my local preferred roads.
Yesterday I made the decision to change the oil myself and put 7.5w Fuchs racing fork oil in and apart from knowing how much was in each leg (and looking at a few youtube vids on KYB forks) I had no idea what to expect inside.
LH leg 1st, was easy to drain and the spring on this side seems to be below the rod as I couldnt even see it. Got approx 295cc out of it and was happy there was no more in. Replaced it with 297ish cc or 10fl oz, put it back together then back on the bike no probs.
The RH leg is completely different and has a plastic spacer come spring guide that is approx 200mm long with the spring below it. You have to compress the spring with the spacer/guide to get to the nut underneath with a spanner to hold while you take off the fork cap. Once done you can remove the spacer/guide & spring.
Getting the 427cc out of this leg is some task pumping the rod in and out (I put the fork cap back on for something more substantial to hold onto) pumping the rod in and out then the outer part of the fork between times and slowly but surely I got just over 400cc but the damper was nice & free (ie just air inside).
filling the oil was less hard work putting some in then pumping until air purged & repeating until happy that around 425cc in & damping rod movement consistant, back together as it come apart then back on the bike.
Made sure everything tightened up and went out this morning down my local twisty bumpy road, ended up really happy as the harshness has lessened so now it is better than the demo bike, is more comfortable on my elbows but doesn't dive as initial test ride.
As I was unsure of what to find I had no thought of videos or photo's unfortunately but wasn't prepared to wait for exploded diagrams or torque settings (I went off previous jobs I did on my Tiger800).
what Wt is the factory?
 
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