Honda CX 500 Forum banner
1 - 6 of 6 Posts

·
Registered
Joined
·
63 Posts
Discussion Starter · #1 ·
So I'm looking at swapping the front end of my CX500 with a GL500 Interstate for the dual rotor / caliper look. The only thing I'm not crazy about (aesthetically) is the air hose and fillers on the top of the fork tubes.

I was wondering what I'd be losing (other than adjustability) by swapping in some simple fork tube plugs (like these assuming they'd thread in)
 

·
Registered
Joined
·
263 Posts
When I did my front fork seals on my GL I put in a spacer to firm it up a bit and stopped using air altogether. I found the air pressure did not hold indefinitely and you have to keep checking/adjusting.
 

·
Registered
Joined
·
400 Posts
You will not loose anything if you swap fork caps - if you swap the front fork springs.

Your OEM front suspension setup makes use of a steel spring and "air" spring. The air spring is further strengthened by allowing you to add a small amount of additional air pressure. I think the OEM setup isn't very good (its not very linear) as you have the oil level and air pressure combined with a nonlinear rate spring to make the ride uninspiring. Get a good quality linear rate spring, lower the oil fill about 2" and get the right preload spacer in there to set the rider sag correctly. You ae not making the bike into a knee dragging special, but you will be amazed at how nice and planted the ride is now. BTW, throwing in a RT GVE would be another good change.

While you are making the front fork swap, don't go with the stock GL500 240mm front discs. Look for a set of GL1100, CB900, or certain CB750 front caliper brackets. They will bolt up to the GL500 forks but position the calipers to fit 276mm discs. You will like the better braking power.

Jerry
 

·
Registered
Joined
·
63 Posts
Discussion Starter · #4 ·
Jerry, thanks for that helpful breakdown of the air suspension. And nice one on the larger diameter discs. I will go that route.

A few questions:
1. When you say get a "good quality linear rate spring", are you referring to a spring kit from Progressive Suspension or the likes?
2. What is a RT GVE?

And just to be clear you're saying reduce the amount of fork oil put back in and stack a 1-2" spacer on top of the spring to set the rider sag?
 

·
Registered
Joined
·
400 Posts
Some claarify comments vegas,

Most people go to Racetech to get their linear rate springs. They have good hardware, but every now and then your order a spring with X lb/in rating and get one slightly off - but don't let this put you off from using them. Check with them or check their web site, then order via amazon for best price.

RT GVE = Racetech Gold Valve Emulator. This is a nice upgrade to the damper rod suspension that is OEM to te CX, The GVE allows you to separate the rebound from compression damping circuits in the front fork. You have to experiment bit, but the results are worth it. Try searching on this site to see what other riders have used for GVE settings

On the oil level, the factory always has a high oil fill level (because they have soft progressive rate, or 2 rate springs). The level in the fork sets the volume of the air chamber in the fork. The more oil, the less air. When the fork compresses, the air pressure inside the fork goes up 2x when you cut the volume in half. Every time you cut the volume in half, the pressure doubles again. You can see when you are getting close to full compression, the pressure can get quite high. When you use the air fill, the factory only recommends only adding small amounts. You would be starting with 14.7 lbs/in (ambient) and going from there. Add 10 psi, then you start at 24.7, so it doesn't take long to get keep the fork from fully compressing especially if you have the factory oil fill in the fork. You can also see there is no advantage to getting progressive springs when the oil fill gets you an overall progressive rate spring. So, get a strong straight rate RT spring where you move more of the capacity to the steel spring and less from the air spring. Start with 2" less oil fill level than OEM setting (measured from the top of the compressed fork with spring out). Make sure the spacer you cut (PVC pipe works) to set correct rider sag for your weight. Remember, you can always add more oil if you need more top end capacity to keep from bottoming out. A zip tie on the fork helps you track how much of the suspension you are using, so get one on the fork now to see how much of the suspension you are using now.

Did this help?

This pic will not stay up long, but perhaps you can see what a GL looks like with the bigger 276mm discs. This was my 81 GL with GL650 forks/brace with GL1100 wheels (I liked the older style Comstar wheels) with the bigger front brakes and a rear disc. These are all straight forward swaps.

 
1 - 6 of 6 Posts
Top