Fork Oil Change

[Guest MikeC]

Anyone out there in the 200 pound range. What weight and amount have you used. I want to change the fork oil before the bike goes into hibernation.

 

Mike

[BrianG]

If you are going to disassemble the forks to change the oil anyway, I'd change the springs while you are at it. 1.05kg springs will be about right.

 

Use something like Spectro Gold - Light Fork Fliud.

 

Stuff labled "Fork Oil" is better for non-cartridge forks.

[Guest MikeC]

If you are going to disassemble the forks to change the oil anyway, I'd change the springs while you are at it.  1.05kg springs will be about right.

 

Use something like Spectro Gold -  Light Fork Fliud. 

 

Stuff labled "Fork Oil" is better for non-cartridge forks.

63523[/snapback]

Brian,

 

I wasn't planning on a complete disassembly. I was hoping the procedure was similiar to my California.

 

Unscrew tops, remove whatever comes out on it's own, tip upside down pump a few times let drain.

 

Since you mentioned springs. Where do you get the new springs from?

 

Mike

[dlaing]

traxxion is a good place for single rate springs. (allegedly lighter than racetech springs)

Ratchethack got some Wilbers progressive springs

Most 'experts' go with lighter than 10weight oil in our forks.

If you are on a budget, the least you should do is add a longer pre-load spacer.

[Guest ratchethack]

I'm still sorting out the front sag with preload spacers (will be going to shorter spacers and raising the tubes even higher in the triples), but the new, stiffer .7-1.0 kg/mm progressive springs from Wilbers made an immediate, very significant improvement over the stock .6 kg/mm weaklings. (I weigh 175 lb.) The first impression was, "Where'd all the brake dive go, and how'd I ever put up with it??!!" I was on the fence on what fluid to use and stuck with 10 wt "fork oil", but after the first ride I realized this was a mistake. I know, I know - many of you have advised against "fork oil" in the Marz forks. I've got Spectro 125/150 "cartridge fork fluid" ready for the next disassembly & change-out. I'm hoping to get a "round tuit" before the EuroMotoFest West Rally this weekend in Valley Center, co-sponsored by SoCal-Guzzi.com and the Ton Up Club of San Diego. You goin', Dave? From what I understand, in addition to some of the usual suspect Guzzisti, including Bill Ross with his '52 Falcone, there'll be a considerable Laverda contingent, as well as Vincent, BSA, and Triumph Guys.

[Guest MikeC]

I'm still sorting out the front sag with preload spacers (will be going to shorter spacers and raising the tubes even higher in the triples), but the new, stiffer .7-1.0 kg/mm progressive springs from Wilbers made an immediate, very significant improvement over the stock .6 kg/mm weaklings.  (I weigh 175 lb.)  The first impression was, "Where'd all the brake dive go, and how'd I ever put up with it??!!"  I was on the fence on what fluid to use and stuck with 10 wt "fork oil", but after the first ride I realized this was a mistake.  I know, I know - many of you have advised against "fork oil" in the Marz forks.  I've got Spectro 125/150 "cartridge fork fluid" ready for the next disassembly & change-out.  I'm hoping to get a "round tuit" before the EuroMotoFest West Rally this weekend in Valley Center, co-sponsored by SoCal-Guzzi.com and the Ton Up Club of San Diego.  You goin', Dave?  From what I understand, in addition to some of the usual suspect Guzzisti, including Bill Ross with his '52 Falcone, there'll be a considerable Laverda contingent, as well as Vincent, BSA, and Triumph Guys.

63557[/snapback]

ratchet...What are the correct dimensions of our springs. Basically what will I need to know before the guy I place the order with asks.

 

Do I really need to completely disassemble the forks to simply change the oil. If so is there a procedure anywhere or is it one of those jobs that don't need a procedure. IOW's the procedure comes with looking at the parts in hand.

 

Mike

[big J]

Idid mine at the weekend, just tipped them upside down and refilled.

 

Dont do what I did and refill with 20w. Far too thick.

[Guest ratchethack]

ratchet...What are the correct dimensions of our springs.  Basically what will I need to know before the guy I place the order with asks.

 

Do I really need to completely disassemble the forks to simply change the oil.  If so is there a procedure anywhere or is it one of those jobs that don't need a procedure.  IOW's the procedure comes with looking at the parts in hand.

 

Mike

63567[/snapback]

Mike, the dimensions of the stock springs are: 25 mm ID, 30 mm OD, and 29.5 cm free length. Yep, you need to get the fork tubes out of the triples to drain 'em, unless you've figured out a way to turn the whole bike upside down without dumping all the other fluids on the bike . I've been threatening to drill, tap, and plug the fork lowers so they can be drained from the bottom ever since my first fork oil change. But when you get it apart, you can see that it's a "non-trivial" thing with considerable risk of missing the target with a drill press. It's not hard to imagine that the price of not hitting the bulls-eye would be substantial - so I've chickened out every time. Best to follow the procedure in the service manual, but not absolutely necessary. Also, the service manual says you need to separate the fork lowers from the uppers, and this is NOT necessary. Once the caps are off (loosen 'em before loosening the pinch bolts!), just remove the tubes, dump 'em out, and pump 'em a few times with the springs out. I've been careful to get the free length of the threads under the spring nuts the same as stock (22 mm showing) each time. Set the cap adjusters full counter-clockwise (without forcing 'em) first, and take the damper adjustment rods out too, or they'll fall out . It's a guaranteed big mess, so make sure to have lots of old towels close at hand.

[richard100t]

I refilled mine with 10wt. I weigh about 170lbs & the front end just feels like its too stiff. I dont know much about setting the compression & rebound on the forks but after some fiddling I think its about as good as its going to get. Next year I think I'm going to have a pro look at it & help me set it up. I dont know if 5wt fork oil would help it or not.

[Guest MikeC]

Mike, the dimensions of the stock springs are:  25 mm ID, 30 mm OD, and 29.5 cm free length.  Yep, you need to get the fork tubes out of the triples to drain 'em, unless you've figured out a way to turn the whole bike upside down without dumping all the other fluids on the bike .  I've been threatening to drill, tap, and plug the fork lowers so they can be drained from the bottom ever since my first fork oil change.  But when you get it apart, you can see that it's a "non-trivial" thing with considerable risk of missing the target with a drill press.  It's not hard to imagine that the price of not hitting the bulls-eye would be substantial - so I've chickened out every time.   Best to follow the procedure in the service manual, but not absolutely necessary.  Also, the service manual says you need to separate the fork lowers from the uppers, and this is NOT necessary.  Once the caps are off (loosen 'em before loosening the pinch bolts!), just remove the tubes, dump 'em out, and pump 'em a few times with the springs out.  I've been careful to get the free length of the threads under the spring nuts the same as stock (22 mm showing) each time.  Set the cap adjusters full clockwise (without forcing 'em) first, and take the damper adjustment rods out too, or they'll fall out .  It's a guaranteed big mess, so make sure to have lots of old towels close at hand.

63571[/snapback]

ratchet...I figured on taking the forks out of the tree. What threw me off was all the talk of taking the actual forks apart themselves. I take it the springs just come out as do the rods.

 

What do you mean by "free length of the threads under the spring nuts the same as stock (22 mm showing) each time."

 

Also when you state set cap adjusters full clockwise do you mean from the start before I lossen the caps.

 

Thanks and sorry for all the questions.

 

Mike

[Guest ratchethack]

Mike, if you're changing out the springs, you'll need to remove the nuts that secure them at the top. These nuts can be set anywhere in a range, and I haven't been able to determine if or exactly how this affects preload (or what the range of adjustability is, if any), so I put 'em back where Mandello set 'em and adjust preload entirely with spacers. The stock setting of the nuts is 22 mm from the top of the nuts to the top of the threaded part. You'll see. RE: fork cap adjusters (compression and rebound), I was WRONG when I said clockwise, I meant COUNTER-clockwise (see edit above), sorry. Yep, the service manual makes a point to have you set them to the lowest notch (without forcing anything) before you take the caps off. Why is this important? It's yet another Mandello mystery to me, (could this let the oil drain out easier?) but that's what it says.

[Steve G.]

Anyone out there in the 200 pound range.  What weight and amount have you used.  I want to change the fork oil before the bike goes into hibernation. 

 

Mike

63502[/snapback]

Save your money with the springs. Put 5w oil in, it will change things for the much better. I am 240ib, and this is working great for me.

Ciao, Steve G.

[Guest ratchethack]

Save your money with the springs. Put 5w oil in, it will change things for the much better. I am 240ib, and this is working great for me.

Errrrrrr........IMHO, per my experience and per the literally dozens of similar opinions on this forum from those who have also done it (and who are also more [ahem] gravitationally endowed) - anyone of 200 lb or above who doesn't go considerably stiffer on fork springs is substantially missing the fabulous handling capability engineered into these machines. Of course, as always, YMMV.

[BrianG]

Errrrrrr........IMHO, per my experience and per the literally dozens of similar opinions on this forum from those who have also done it (and who are also more [ahem] gravitationally endowed) - anyone of 200 lb or above who doesn't go considerably stiffer on fork springs is substantially missing the fabulous handling capability engineered into these machines.  Of course, as always, YMMV.

63658[/snapback]

 

 

Ya, that!!

 

With OEM being around 0.6 or 0.7, and the appropriate ones for 200+ lbs PLUS riding gear being 1.05 or 1.10 there's no way that preloading or over-damping the forks will get optimum fork action.

 

I like my street bike to show about 15-20% free sag and about 30-35% loaded sag, front and back. This will yield a great cushy ride with fantastic control. The "light" Fork Fluid is about 5 -7.5 wt, and is correct for the Marz valving.

 

I don't believe that HARSH = OPTIMIZED suspension. Neither do winning racers.

[dlaing]

(and who are also more [ahem] gravitationally endowed)

63658[/snapback]

Hey! Who you calling endowed!

Springs are pretty inexpensive compared to the thousands that some one percenters spend on upgrades like OHlins

Steve is not the first Canadian to suggest that their bike was adequately sprung....could it be that the Canadian bound models came with heavier springs??????

EDIT Brian, did you measure sag with the OE springs?

Adding preload and lighter fluid could make it better for little money, but a heavier spring, proper sag and lighter fluid should make it much better.

I am also interested in the air spring effect of varying fluid height.

To measure the varying effect, you can remove the spring and reassemble with varying fluid levels and seeing how much force is required to bottom the fork.

WARNING if fluid level is too high, bottoming will occur on the air cushion and travel will be limited.

and if too low, cavitation may occur.

I also theorize that you should have just a little more preload on the rebound side.