soft front shocks

Hi all


can any one tell me how to stiffen up my fork they bottom out .i havent noticed any oil leaks how do i get the oil in .


thanks john

 

It is possible all the oil has leaked out and you are just running on the spring pressure. To add oil (make sure you know how much and of what grade BEFORE you start - read look it up in the owners manual, haynes/clymer manual or XJCD).

1. You should have a rubber cap at the very top of your forks - remove it, it should just pull out.

(afterthought: At the bottom you should see a small screw on the side of the fork - this is the drain screw. Loosen it and see if you really have no oil before you go any further)

2. Below the rubber cap, you will see a metal "slug" held in with a snap ring. You need to carefully remove the snap ring by exerting pressure on the slug to conpress the spring inside. If you get it loose, BE CAREFUL you just don't let the pressure off or you will get it and the spring in the face!

3. Once the slug is out, you have access to inside the forks - put the oil in.

I would recommend that you replace the fork seals. You don't want to put the oil in just to watch it leak out. Also, you should check the drain screw isn't leaking and the retaining bolt at the bottom running into the fork (not across for the axle) is tight with a copper washer to prevent leaks.

I am sure others will expand on what I have written and offer some tips and tricks but this should get you started with the info you need.

Good luck!
Rob

 

I had a slight leak in my left fork.
I replaced the fluid with 20 weight and it made a world of difference in the softness and so far I've seen no leak.
Not saying the leak is fixed but so far so good.

 

The manual for my Seca recommended 10 weight fork oil, but unless you're 90 lbs or want a softer ride, I'd go with a 15 or 20 weight. Also, if the fork oil hasn't been changed in a long time, you may find the "slug" rusted in place, as mine was.

 

Sure sounds like they're low or out of oil. This sounds like a good time to do the full job - take the forks off, drain any remaining oil, replace the seals, refill with new oil, and re-install. Takes a couple of hours, but you'll be happy with yourself afterwards!

I've put Progressive springs in my forks, but as I'm 260lbs I went with the 20 weight oil -- works great.

 

Yessir, I have the 10 Weight oil in my forks and find it soft as well. I'm also topping the scales at 6'4, 275lbs and the bike lets me know it it some of those dips and surprise pot holes. I think I'll give the 20 weight a shot after this season. Thanks for the tip Altus!

Rob

 

Yer a BIF guy you will need to either increase the preload .. stuff a spacer on top of the spring OR cut the spring to increase it's rate, then add a significant spacver to make for the length removed + some for preloading. That and 20 w Fork oil should help some.

 

Yeah - with the Progressive springs in the forks they suggested a spacer around 2". I went with one a little over 5" long -- the spacer just comes to the top of the tube when all extended, so giving about 1.5" of pre-load. If I'd gone with their suggestion, there'd be no pre-load whatsoever on the springs.... gotta watch those "suggestions" from the factory

 

What are you using for spacers? Just some steel bar?

 

PVC, aluminum tubing, steel tubing. I've heard and seen all three used. Heck, I'm running PVC right now. I will be using aluminum as soon as I can find a place that carries the right diameter.

 

I'm using a piece of PVC pipe, with large steel washers top & bottom.
Seems to work just fine.

 

Cool - thanks.

 

Hey Dispatcher, I'm having trouble finding a straight answer to how much fork oil should go in there . ... does 8 ounces sound right to you or 6 inches from the top of the tube
thanks for any advise...
milo

 

milo, you didn't tell us what model of bike you have, here's some info.....

The Yamaha manual for the XJ750RH states the fork oil capacity (each side) as 309cc (10.5 oz) and to use Yamaha Fork Oil 20Wt or equivalent. The standard air pressure is listed as 0.4 kg cm2 (5.7 psi)

The XJ650G section states the fork oil capacity (each side) as 262cc (9.24 oz) and to use Yamaha Fork Oil 10Wt or equivalent.

 

thanks Nick ! I have a 550 like the one I see in the Dispatchers pic's...
not nearly as nice though

 

You will need 230cc of 15 or heavier fork oil. Just did the forks on PBR's 550 today. The slugs were a pain to install (small suprise right?). Standing length of the springs should be 508 mm (minimum, more is good). I ought to buy a 550 book given all the 550 ginks out there. Nice little rides. Where abouts are you located Milo?

 

Excellent Robert, I'm in the SF Bay Area ... now I need to find out how many cc s are in a ounce or ml ect...
hmmmmmm.
7.8 ounces

thanks for helping

 

Conversion formula is easy to find. Use the Ratio-Rite and you'll have both handy. Good investment of $8. Hey, Seca550_SF is out in your neck of the woods, you ought to get in touch with him. I'll see if I can't get his email for you. He is just starting out on his toy and is looking for a wrenching buddy. Might be nice to have a riding buddy too!

 

Milo, that Porsche in the background there sure does make up for the nice though!

 

this thread got me to jump in there, I found the rust kinda helped hold the slug down while removing the circlip ... then loosen the 12mm bolt at the top of the tube and in this case a pull pin was welded to the slug so a slide hammer could help it out...

 

...

 

...

 

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...,

 

...,

 

...,.

 

...,.,,

 

... .. 7.8 ounces

 

Heck of a job there Milo! Color me impressed! Not too many of us have a spot welder laying around to pop a puller pin in there. Just a thought but the caps off of an 80 XS 750 have an air valve in them. I just found the correct thread pitch, popped a corresponding bolt in there, grabbed a pair of vise-grips, clamped down, slid a screw driver shaft through the jaws, held onto the handle and whacked the shaft between the handle and the vise-grip. Popped out nicely. If I recall correctly from this weekends escapade, the slugs were the same size. Might be a good investment.