Much difference in fork springs - .37kg/mm to .38kg/mm

[dirtballer]

On my 99 220r, I've determined that Fredette's .38kg fork springs are the best for my weight and type of riding (168lbs, all woods). But would going to a .38 spring make any noticable difference if stock spring is .37kg?

I don't have money to throw away at present. Am I better off just changing the oil, messing with the preload, and maybe removing a few valve shims?

Thanks!

 

[Tom68]

Depends on freelength as well.

 

[glad2ride]

The stock springs are .35. I have actually taken a rate measurement on a set.

Are you 168, or are you 168 with all your riding gear on, plus water back (if any) and any tools?

 

[dirtballer]

I'm 168 lbs in my whitey tighties ;) I ride woods in MN and WI but would like to take an occasional jump without bottoming out. .35kg sounds more plausible, but I have seen .37kg quoted a number of places - thus the confusion.

.

 

[dirtballer]

Can someone give me the part number(s) for the fork seals that are commonly replaced when installing new springs? I think it is reference # 92049-1316 (92049-1373) or 92093-1260 or both.

I'm thinking I can tackle this on my own. Will I need to fab a pvc spacer (I read they do that with xr400 springs) with Fredette's springs?

 

[glad2ride]

If "YOU" are 168, then you are around 183 or so with gear on. Race Tech (www.racetech.com) and MX Tech (www.mx-tech.com) both recommend .42. If you can find some used Honda XR400R springs from the later models (around 1998/1999 and newer, not the earliest years, as they were .38), they are .40. That may be a cheap alternative.

I strongly suggest you cut a PVC spacer with FRP or XR400R springs. FRP Offroad springs usually come with a length of PVC pipe with them.

The part number on the seals is what you want, not the reference number. The part number for the oil seals is 92049-1373. They come one to a package, so you will need two. The part number for the dust seal is 92093-1260. Again, they come one to a package, so you will need two.

Heat up a couple of gallons of boiling water to pour over the seal area before disassembly. It will make it easier to pull the tubes apart and may prevent damage to the bushings. The inner and outer bushings are 10 years old, so be aware that replacing them is also a good idea.

 

[dirtballer]

I strongly suggest you cut a PVC spacer with FRP or XR400R springs. FRP Offroad springs usually come with a length of PVC pipe with them.

So what exactly does the spacer do, and how big do I make it?

I think I'll buy the FRP .38 springs (would be nice to find a .39 spring). What oil weight is recommended?

Thanks,
Mark

 

[Tom68]

The spacer sets your sag height. Be very careful not too have the spring coil bind before the fork bottoms, if you add spacer length meausre collapsed height to be sure.

 

[lemmy]

So the spacer is for setting preload? What is wrong with the stock spacer?

 

[Tom68]

So the spacer is for setting preload? What is wrong with the stock spacer?

Nothing wrong with std spacer with the std spring or any spring with the same or lower scragged height.
Because the springs are 1980-90's soft you need a lot of preload to get a decent ride height, I'm using the 1980's fix, air pressure it gives massive spring rate as you approach bottoming but still leaves the frontend trail plush higher in the stroke.

 

[lemmy]

The guy I bought mine off of said racetech gold valve and springs had been installed. But of course there is no way to know. But I have been happy with my front suspension and I have let 2 others ride it (and one has been riding for years) and they both liked the front suspension better than their own bikes (one is crf250 and the other is ktm 450exc), so I guess he is telling the truth. I never find any info on the front suspension (what sag should be, how high the forks should be in the clamps, etc) on the web, all info seems to be on the rear shock only.

 

[lemmy]

So buy saying you use air, are you saying you just put more fluid in your forks?

 

[Tom68]

So buy saying you use air, are you saying you just put more fluid in your forks?

No, I run the fork oil at minimum spec so the compression doesn't become ridiculous, I've Tee'd the forks into a schrader valve. The std springs have lost free height and have no preload, for dirt track I run 0psi, for trail I run 12-15 psi and for tracks with doubles and long table tops I use 20psi. When I get a bit better at the jumps I may come back to 15psi but when you land in the face of a double you need a bunch of spring. Whilst it's accepted practice to purge modern forks thats because they run decent spring rates .42-.46, after purging they still have atm' press' in them and that compresses to significant internal pressures @ full stroke especially with 49mm forks and the like.

 

[Tom68]

The guy I bought mine off of said racetech gold valve and springs had been installed. But of course there is no way to know. But I have been happy with my front suspension and I have let 2 others ride it (and one has been riding for years) and they both liked the front suspension better than their own bikes (one is crf250 and the other is ktm 450exc), so I guess he is telling the truth. I never find any info on the front suspension (what sag should be, how high the forks should be in the clamps, etc) on the web, all info seems to be on the rear shock only.

Sounds like you'll have decent spring rates then, having an experienced rider jump on is a good idea, my mate that races supercross rode mine in the woods with 12psi in the forks he said whilst it was trail friendly I shouldn't be jumping it.

 

[glad2ride]

AUS guy, I am waiting on the day your fork oil shoots out like a water fountain. Dude, get the correct springs.

Eibach 996 model springs fit. They are in odd numbered rates. You need to check the www.mx-tech.com and www.racetech.com spring rate calculators.

The spacer is cut to set the proper amount of preload on the spring (around 10mm). The spring is preloaded (already compressed) 10mm, not that the spacer is 10mm. You could cut the stock spacers to the correct length. It may be easier to do with the PVC.

 

[Tom68]

AUS guy, I am waiting on the day your fork oil shoots out like a water fountain. Dude, get the correct springs.

Eibach 996 model springs fit. They are in odd numbered rates. You need to check the www.mx-tech.com and www.racetech.com spring rate calculators.

The spacer is cut to set the proper amount of preload on the spring (around 10mm). The spring is preloaded (already compressed) 10mm, not that the spacer is 10mm. You could cut the stock spacers to the correct length. It may be easier to do with the PVC.

Done all the calculations don't hold your breath.

 

[glad2ride]

How about you don't jump anything larger than a kangaroo poo?

 

[Tom68]

How about you don't jump anything larger than a kangaroo poo?

Still working my way up to one of those.

 

[glad2ride]

On a hard hit, you are going to push oil past the seals.

 

[Tom68]

No thats just icecream on his lips