Breva V1100 fork oil change

[GrahamNZ]

Breva V1100 fork oil change (Norge and Sport may differ somewhat)

Changing the fork oil on a regular basis is a good idea. While oil doesn’t “wear out”, it becomes contaminated with wear particles and moisture. If all feels well with a new bike I’ll leave changing the oil until the bike is one year old and thereafter change the oil at two yearly intervals. The handbook calls for 400cc of oil (5W up to 20W – that's a big viscosity range!) per leg. I opted to use 450cc of 15W for increased damping, and air-springing effect at full compression. As it turned out I measured 450cc of oil removed from each leg. When you consider that all the oil is not able to be saved and measured, I estimate that each leg had been given about 470cc at the factory. The old oil was darkish in colour, indicating wear particles, but otherwise quite clean looking and with none of the yellowing which moisture causes. In the saved oil there were the normal metal specks from running-in but nothing of concern. Viscosity was difficult to judge.

The task took slow old me 2.5 hours, which included time for coffee as the legs drained of kerosene, but a real mechanic would probably do it in 2 hours or less.


Here's how I went about the task:
• Place the bike on the centrestand and place timber blocks under the sump so that the front tyre is clear of the floor.
• Loosen the outer handlebar riser screws accessible from under the fork crown. (top triple clamp) This is necessary to allow the crown to open and release the stanchions when the pinch screws are loosened. (In-hex 6mm)
• Loosen the fork leg top plugs now. (28 mm socket)
• Loosen the crown pinch screws to release the stanchions. (In-hex 6mm)
• Remove the front mudguard. (In-hex 4mm)
• Remove the brake calipers and leave them on the hoses. (In-hex 7mm)
• Disconnect the speedometer sensor from the right slider lower. (8mm socket) Cut away the two small cable ties fixing the cable to the slider inner lugs.
• Remove the front wheel. (In-hex 5mm for axle pinch screws and 30mm socket for axle nut) (see "Breva front wheel removal")
• Note how many stanchion rings are showing above the crown. (mine had 3, which happens automatically if the stanchions are pushed up hard against the top stops)
• On one leg, loosen the paired pinch screws of the fork yoke. (bottom triple clamp)
• Slide the fork leg down and out of the bike. (Be ready in case the leg decides drop out!)
• Repeat for the second leg.
• Grip each fork stanchion lightly and vertically in a vice using jaw soft protection and remove the top plugs. (which come out easily but need a little downward pressure against the spring as you do so to ensure that the bottom threads are not damaged as the plug comes free)
• Push the stanchions into the sliders and remove the springs. (the top of the spring is of smaller diameter than the bottom)
• Invert the legs over a container and drain out all the old oil. At the same time the spacer tubes will come out and likely drop into the oil. Pump the legs in and out full stroke several times both upright and inverted to achieve complete drainage.
• Add about a cup of kerosene to each leg, pump upright and inverted full stroke several times, then drain to wash the internals. Allow to drain inverted for a about half an hour at least.
• Wash the springs and spacers with kerosene and allow to dry.
• Add new fork oil and pump the upright legs several times full stroke to prime the damping chambers.
• Extend each leg fully, hold the stanchion vertically in the vice and refit the spacer tube, spring, and top plug after lubricating its sealing O-ring. (Again, apply a little downward pressure against the spring as you start to screw in the plug to ensure that the bottom threads are not damaged as the plug starts to engage)
• Refit the fork legs, pushing them up until they come against the top stop, and tighten the yoke paired pinch screws.
• Tighten the top plugs now.
• Loosen the yoke pinch screws again and rotate the fork stanchion so that the top preload adjuster marks are sensibly and equally placed and ensure that the correct number of stanchion rings are showing above the crown.
• Re-assemble everything else in reverse order.


Note
The plastic spacer tubes measured 38mmOD x 32mmID x 204mm long. I wouldn’t recommend increasing the length to firm the suspension because it won’t achieve that. All it will do is raise the ride height. If firmer springing is wanted then the answer is to fit firmer springs.

[Roblatt]

thanks Graham,

I've always wandered about that last "note" and the stiffness.

Robert

[Joe breva1100]

Cheers Graham,

When I did mine I neglected to measure what drained out so the 400cc of oil I put back in again may not be enough, the front end feels ok though.
I was not sure what weight oil to use, I used 5w because thats what the bike came from the factory with. I'm due another fook oil change in about 5000 miles so I may try a heavier oil then.

[NeroGuzzi]

...Always grateful for the step-by-step instructions, Graham. Thanks again.

[3ackok]

Graham, thanks for the detailed write up. I have a question- how do you determine the quantity of oil to fill the fork?

[GrahamNZ]

Not sure exactly what you're asking so let's cover the field!

The Breva specs call for 400cc of oil per leg. Some of us have decided to increase the volume to provide more air-compression-springing effect at near full fork compression, which can occur when hitting a big bump while braking hard. In my case I went with a recommendation to use 450cc per leg. from what I managed to drain and collect from my forks I'd guess that the factory had put about 480cc in each leg. On that basis I imagine that even 500cc per leg would be OK. Vastly too much oil could cause oilseal problems and a fork completely filled would suffer hydraulic lock. Has anyone used 500cc per leg satisfactorily?

I use a measuring cylinder to add the oil.

The specs also say to use oil of 5W to 20W viscosity. That is a huge range. Again, like some others I opted to use 15W for more comression and rebound damping effect. As others have observed, the Breva is quite lightly sprung, which makes for a comfortable ride but a bit lacking for a sporting ride, which IMHO is not a Breva's forte anyway. With soft springing, problems can occur if the damping is too great for the spring strength, when hitting a sharp bump can see the damping take the shock before the spring does its job, giving the harsh effect of a spring which is too firm. At the other end of the scale, driving over a rippled surface can cause the suspension to "pack down" if the damping is too great for the spring strength. On a Breva the fork damping isn't adjustable except by altering the oil viscosity.

At the rear the rebound damping is adustable but the oil viscosity isn't. Fitting a firmer spring to the original suspension unit might work OK, but it may find the damping out of synch. If I was to upgrade the rear suspension I'd be looking at a new suspension unit with either the spring strength and damping factory-balanced, or one with adjustable compression and rebound damping.

At the risk of preaching even more, it's worth repeating that increasing spring preload doesn't make the spring firmer, it merely alters the ride height.

[2Laner]

Graham, The 1st time I changed my fork oil I drained out about the same as you did. Pretty close to 500 cc. I opted to add a shade over the manuals recomendation of 400cc's. Seems to work for me. I thought maybe factory overfilled, as some other items i.e. TPS settings, from factory were not always correct. I'm 160lbs but load the bike up frequently for weekend camping excursions. At any rate 450cc seems a safe value.

[3ackok]

GrahamNZ wrote:

Not sure exactly what you're asking so let's cover the field!

Sorry for the vague question, the reason is that I've never taken a fork apart. I noticed that the manual is very specific about amount of the replacement oil- 400 ml +/- 2ml. This is 0.5% tolerance, which is rather tough, and hard to achieve at home. You can't just pour two glasses of oil- it will have to dosed by a special measurement vessel or some similar device. Furthermore, refilling with such precision will require that at least 99.5% of the old oil is drained. Again, I've never worked on a fork, but in my experience draining engine or transmission oil is to this extent is not possible (not routinely anyway). So the question is- how do you know that the amount of oil is correct- should the oil be filled to a certain level which can be tested? What will happen if the total error will reach realistic 10% and the fork will end up with 440ml of oil?

[GrahamNZ]

3ackok

I think that if you read my original post again your questions will be answered.

[3ackok]

I attempted to change the oil, but run in a trouble at the beginning. When I tried to loosen the top plugs, I was able to turn them only about 180 degrees. I used a considerable force, but couldn't move them any further. Happened on both legs. What did I do wrong?