soft front forks

[Guest]

I recently re-redid the front fork seals. All seemed to be good, there are no visible leaks of fluid and it is holding air.

now they provide no resistance except for the springs. they bottom out just rocking it and holding the brake.

air pressure is where its supposed to be, and showed no sign of leaking with soapy water test.

ideas?

[bwringer]

Sonic fork springs.

No air pressure.

[detorn]

Sonic fork springs.

No air pressure.

it's holding air fine though, even over inflated to check. I would like better springs eventually, but I don't think thats my current issue.

[tkent02]

Sonic fork springs.

No air pressure.

[Agemax]

no air pressure

wrong oil weight/level

[Steve]

it's holding air fine though, even over inflated to check. I would like better springs eventually, but I don't think thats my current issue.

No, your 'current issue' is that your stock springs, which were too weak when they were inserted in the tubes in Japan, are even weaker now, and REALLY need to be replaced.

Progressive fork springs are about $75 from Z1 Enterprises, Sonic springs are about $80, direct from Sonic. For what it's worth, the owners of both of those places are members here, and I don't think they will be offended if you choose the other's springs.

With either one, you will get a better spring rate (you can choose the rate with Sonic) and will not have to add ANY air to hold the front end up.

The quantity or viscosity of oil in the forks will not determine whether you can bottom the forks, only how quickly you can bottom them. To keep from bottoming, you need spring pressure. The oil just keeps the motion slower and smoother.

.

[gsgeezer]

Sonic fork springs. No air pressure.

No problems!!

[gsgeezer]

Also, cartridge emulators are great, too!

[mmattockx]

I recently re-redid the front fork seals. All seemed to be good, there are no visible leaks of fluid and it is holding air.

now they provide no resistance except for the springs. they bottom out just rocking it and holding the brake.

air pressure is where its supposed to be, and showed no sign of leaking with soapy water test.

ideas?

How were they before? Do you have the same amount of air pressure in them after the seals as before? Did you replace the oil with the same weight and amount? Did you forget to put the spring preload spacers back in? How much static sag did you have before? How much sag now?

It sounds to me like your oil is way low and allowing the easy bottoming or you forgot the preload spacers on top of the springs.


Mark

[kdo58]

Sonic springs

[tkent02]

No, your 'current issue' is that your stock springs, which were too weak when they were inserted in the tubes in Japan, are even weaker now, and REALLY need to be replaced.

The springs don't get weaker from being compressed 30 years, but they get shorter. This combined with the fact that they were much too weak to begin with makes spring replacement mandatory if you want anything resembling a safe bike to ride.

+1 on the cartiridge emulators, too.
The two together with decent rear shocks, if setup correctly, will let it handle like a bike from the nineties. Early nineties maybe.

[detorn]

How were they before? Do you have the same amount of air pressure in them after the seals as before? Did you replace the oil with the same weight and amount? Did you forget to put the spring preload spacers back in? How much static sag did you have before? How much sag now?
Mark

they were fine before the work. they were fine even a couple days after. I suspect I just did something wrong. there are no preload spacers. The oil weight in there I know is not correct as well, but like I said they were good for a day or two after. may finally give in and take it to a shop.

[Steve]

... may finally give in and take it to a shop.

Take it to a shop and all bets are off.

Good luck. Hope you can find a shop that will let it in the door and/or might do a decent job.

There is no doubt, however, that it will NOT be cheap.

.

[derwood]

The forks are not complicated.
You are probably right in that you made some sort of assembling error in one or both forks. There are lots of pics around showing how the go together.
You should take them apart again and find the problem. You probably won't have to separate the tubes.

Better find the issue yourself than to take the bike to some shop and pay them to find out you are an idiot and end up kicking your own ass all the way home.

re-work is pretty common.

if you can afford to take it to a shop, you can afford new springs. If not the old springs can be cut (cut soft end) and replaced with a length of spacer.

the fact that there are no preload spacers seems strange.
is the flat washer with no hole on top of the spring?

[detorn]

is the flat washer with no hole on top of the spring?

no there was no washer at either end of the spring.

edit: looking at the breakout there is no washer at the top, but there is one at the bottom of the spring that I'm pretty sure is not there.