XR Forks

[nos96]

A friend of mine has an 87 XR250. He has heard mixed opinions about how much air pressure should be in the front forks. The local Honda shop said "not much", a fellow rider said 10-11psi, his dad says about 3 psi and he read some where that there should be ZERO psi. I fthere is supposed to be 0 psi, then why would they have the air valve at the top of the forks. The reason we think that somthing is wrong is because when you sit on the bike you lean forward...it feels as if you are going downhill on level ground. Is this normal??? :uh:

 

[James]

Your springs should do most of the work holding your front end up. Older XRs tend to have squishy springs especially if you weigh more than 175 and what you describe sounds normal for XRs. Air pressure should not exceed 6psi

 

[dell30rb]

Hmm. I pumped the xr200 up to 12 psi. And it hasnt had any problems yet.
I also read a super hunky article where he said that some racers would just take te springs out of their forks, pump up and go ride!

 

[DEANSFASTWAY]

If youve had that bike going since 87 the springs are possibly sacked out and the oil is more than likely spent . maybe you should buy a manual to help you find out how to tune your bikes forks , itr will also tewll yoiu how to service them and check the springs . as for air pressure dont go over like 10 - 15 pounds . Maybe if it seems too loose or soft you coulg get yourself some stiffer springs or a little heavier weight oil or ATF . Its really pretty simple if you try . Also firming up the forks on that bike is a good idea as it will make the bike feel more stable. GOOD LUCK in your quest and keep us informed .

 

[nos96]

well granted the bike is an 87, it has been ridden very little. It was used initally by honda for testing when it was new, then used also by honda for pictures in product line catalogs. The suspension was completely rebuilt by "Jake" some popular baja racer years ago. I have faith that the springs are in good shape but could be mistaken, after all its not my bike. But the question is confusing as you can see because as you can see different people have different opinions on the matter. I was just hoping to get a little bit of information from somebody with a similar set-up. Anyways, thanks for all of the help..

 

[James]

My XR400 runs 0 pressure. My XRl650 owners manual says not to run more than 6lbs. From what I remember, the XR600 is the same way. My brothers 95 XR 250 manual says to run 0 lbs pressure even though it has air fittings. From what I remember, my 86 XL250 was supposed to have 0 lbs pressure also but it has been 10 years since that one.

In all cases, the stock setup allowed the front end to dive much like you describe and that is why I say it is normal for stock XRs. They come from the factory with very soft springs with little preload and soft damping. The front end will easily sag 3-4 inches if you weigh much more than 150 lbs. Putting the correct rate springs in all of these XRs to match our weight eliminated the sinking front end. Even if his forks were "rebuilt" doesn't mean that they are sprung correctly

The air pressure is meant to be a supplement and I seriously doubt you could take the springs out of XR forks, pump em up, and go. I think you blow the seals and find yourself on the ground in short order. 12lbs may not be too much but I haven't seen a manual yet that recommends that much air. But I haven't read all of them yet so I could be wrong :confused:

Have your buddy take the springs out and measure them to see if they are sacked out or broken. You should obtain a manual that gives the service limit of the spring length. If possible, you should see if the springs are the original stock springs. If so, they are probably .38 kg springs with little preload. Your friend needs to find out what the proper spring rate is for his weight and make sure the preload is sufficient.

 

[bake]

In some cases it's just a bleed to keep the forks at zero psi, better check the owners manual!