fork oil change

[SpudRider]

Originally Posted by Weldangrind

To slow the damping rate?

Yes, that is exactly correct.

The fork springs provide the general support for the suspension. It is important for the fork springs to be well matched to the weight of the bike and rider. Perhaps CSC will provide a selection of aftermarket fork springs in the future. If so, we can then adjust the forks for riders of different weights, et cetera. As of now, we must accept the factory fork springs.

The viscosity of the fork oil moving through the damping cartridge provides the damping. A lighter fork oil, with lower viscosity, provides fast damping. A thicker fork oil, with higher viscosity, provides slower damping. As set up at the factory, the Zongshen RX3 forks have very fast damping. The stock fork oil has a viscosity of about 2.5W. The Mobil1 Synthetic ATF has a viscosity of about 10W. The thicker ATF slows the damping of the forks, and provides a much smoother, less choppy, fork action.

[fishman10]

since 330ml. Is about 11.2 ounces. I wonder if putting 12 ounces in rash leg would harm anything. ??

[SpudRider]

Originally Posted by fishman10

since 330ml. Is about 11.2 ounces. I wonder if putting 12 ounces in rash leg would harm anything. ??

Trust me, I don't think you could fit 12 ounces of oil in these forks. In fact, you can't pour all 330 ml of oil in at once, or you will surely make a mess while you are trying to work the oil into the damping cartridge.

I have no doubt 330 ml is the correct amount which completely fills the fork to the proper level. If the fork oil is too high, you can create too much pressure in the fork, which can either damage the oil seals, and/or cause them to leak. I strongly suggest you stick with the recommended volume of 330 ml. If you want an even slower rebound, try using a heavier weight of fork oil (15W).

These forks also need stronger springs to stiffen them. However, we don't have that option at the moment. Fortunately, Ryan told me CSC plans to address this issue in the future.

[oldqwerty]

Diablo Rojo, my 3-year old grandson named my bike, is out for delivery today.

We may can do a little good with the stock springs with spacers. Cutting a spring makes it stiffer, and I've had several applications where it was possible to cut a few coils and use a longer spacer to stiffen the ride, but it is imperative to make sure doing so does not lead to coil bind or reduced suspension travel. I'll take a look while changing the fork oil. I intend to change the fork oil per SpudRider's recommendation as part of the initial set up and service. I'm fatter than the Spudster, but my riding will be less demanding on the bike, so I figure using the same Mobil1 Synthetic ATF will serve me well, and I already have a few quarts on the shelf.

[SpudRider]

You are wise to change the fork oil quickly; you will not be sorry you did so.

I think it will difficult to put spacers at the top of the fork, since tightening and loosening the nut on the damping rod is the hardest part of the job, especially if you don't have a very thin, 14mm wrench. You might be able to put a spacer at the bottom of the spring, but you might not, depending on the ability of the cartridge to support the spacer. When you have the forks apart, please do take a good look and evaluate this option for us.

[SpudRider]

Congratulations on the delivery of Diabo Rojo. Tell your grandson I love that name!

[AZRider]

Spud, if you have the spring dimensions, there's a good chance that Progressive Suspension will have something in their catalog that fits. I have Progressives on the front and rear of my Valkyrie and they make a substantial difference.

[SpudRider]

Since changing the fork oil can be a little messy, I didn't take any photographs, and I forgot to measure the springs. Perhaps someone else can measure the springs when he changes the fork oil.

I have talked to Ryan at CSC regarding this matter. I believe CSC is going to contact one of the aftermarket spring manufacturers in the future, and encourage them to offer stiffer springs for the RX3. If stiffer springs are available, I will one of the first customers on the list.

[fishman10]

Of course you are correct spud, you cannot put 12 oz in each fork leg. . What a mess. An now my back tire mysteriously is flat

[SpudRider]

Originally Posted by fishman10

Of course you are correct spud, you cannot put 12 oz in each fork leg. . What a mess. An now my back tire mysteriously is flat

The rear tire of my RX3 also mysteriously went flat while I was riding about 5 miles from home. I limped home on the flat tire, and seized the opportunity to install the Shinko 244 tire several days later.

When I changed the tire I noticed a very small nick in the inner tube. The small hole had not been caused by a puncture, since it was located on the inner portion of the tube, near the rim. The rim strip was in perfect condition, and none of the spokes were protruding from the nipples. I surmise the tube was probably damaged during installation of the tire at the factory.

I replaced the inner tube, but it can certainly be patched. The tube was in very good condition, except for the small nick, which lasted about a week, and sustained about 500 miles of riding before it failed.

[oldqwerty]

Originally Posted by AZRider

Spud, if you have the spring dimensions, there's a good chance that Progressive Suspension will have something in their catalog that fits. I have Progressives on the front and rear of my Valkyrie and they make a substantial difference.

I used Progressive products on a late Nighthawk 750, early CB550 Four (old 4 muffler model), and a CB400 Four (old 4 muffler model). I set the CB750 and CB550 up for me, the CB750 for a body mass of 280 pounds, the CB550 for a body mass of 180 pounds (cancer fight will do that to you), and the CB400 for a body mass of 108 pounds (my wife). Progressive's recommended bolt-ons, some decent fork oil, and some more current tire technologies on the smaller bikes transformed the ride and handling on all three bikes. I'm a firm believer in Progressive's engineering principles for street use.

[Weldangrind]

Originally Posted by oldqwerty

I used Progressive products on a late Nighthawk 750, early CB550 Four (old 4 muffler model), and a CB400 Four (old 4 muffler model). I set the CB750 and CB550 up for me, the CB750 for a body mass of 280 pounds, the CB550 for a body mass of 180 pounds (cancer fight will do that to you), and the CB400 for a body mass of 108 pounds (my wife). Progressive's recommended bolt-ons, some decent fork oil, and some more current tire technologies on the smaller bikes transformed the ride and handling on all three bikes. I'm a firm believer in Progressive's engineering principles for street use.

[hijack]

I can't help but notice that our tastes in bikes are quite similar, especially when TW's are factored in.

[/hijack]

[katflap]

Changed my fork oil today .

With the Cap off, spring removed and fork fully retracted i measured the oil level within the fork.
Prior to measuring i collected all the oil that was dripping from the spring and added it back in to the fork.

The oil level was at a depth of 9.5cm from the top of the fork.

I knew that without fully stripping down the fork i wouldn't be able to remove all the oil and i was keen not to overfill or have un equall amounts in the forks.

What i didn't expect was the difference between the recommened refill amount of 330cc and the 280cc i used to fill mine back up to my measured level.
I double checked this by measuring the old oil i removed. It was 280cc.

I would be interested if others have the same oil level measurement. Perhaps mine was under filled from factory.

[SpudRider]

I don't remember if I measured the used fork oil, or not.

Did you work all the fork oil out of the cartridges? I imagine the fork action is pretty soft with 50 cc less oil in each fork.

[katflap]

Hi spud
Yeah, I gave it quite a good workout. Perhaps not long enough but there only seemed to be a minimal amount of residual oil left

Unfortunately I don't have anything to compare the fork action against. But they don't seem particularly stiff.

I'm hoping that some one who is planning to change there fork oil in the future will do a quick measurement