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Post by medic09 on Dec 6, 2006 20:12:11 GMT -5
As I get a little more understanding with time, I'm noticing that my forks dive pretty freely when I come to a hard stop. Moreso than my 750Four, for instance.
Can I just drain the forks from the bottom, fill them with new fork oil, and see how that goes?
What do you all do to maintain your (stock) forks?
Thanks!
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Post by hopwheels on Dec 8, 2006 1:04:57 GMT -5
You may want to try a heavier weight fork oil after draining, or new springs. I need to handle the same issue on one of my bikes. Dives pretty bad. And with new Progressive shocks in back, it's really mis-matched right now.
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Post by medic09 on Dec 8, 2006 8:50:08 GMT -5
Hi Gary!
Since everything is new to me, I'm a bit hesitant to jump into taking apart my forks (on my 750Four, as well). Hence the question if it's reasonable to start with just a drain and refill. I don't know what weight oil is in there now, so I was just going to put 10W in.
Some PO (at least two owners back) started slight mods on this bike. Aftermarket carb (got rid of it and put on stock, which I quite like), shorter, racier handlebar, and supplemental oil line to the head. So far that's all I've noticed, as I start to understand what I'm looking at. I figure someone like that wouldn't have neglected the forks; but maybe he never got around to caring for them.
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Post by hopwheels on Dec 8, 2006 10:36:15 GMT -5
I understand about the forks being a little daunting. The Clymer's manual I have says 10w is stock. If you want it a bit less spongy, you may try 15, or even 20w. Once you get the hang of older forks though, they're not very complex. The internals on SR's are pretty simple. If you were to do a spring swap, you don't need to take them all apart. You can drop in new springs from the top. The only need to take apart the forks (I think) is seal replacement. So if yours aren't leaking, no problem. Good luck!
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Post by pablosrfivehundred on Dec 8, 2006 14:11:37 GMT -5
I recently installed one progressive spring on the left side to see how much difference it would make. oh man. do it.
completely worth the $50 on springs. go to mikesxs.com and pick up the 650 springs. you'll need to cut a new spacer. they are longer than what you have in there now. I highly recommend it. I might throw the other spring in, but I need to get new rear shocks first, as of right now they are just about even.
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Post by wizz954 on Dec 10, 2006 4:40:37 GMT -5
These old style forks need thicker oil to effectively control rebound damping. I use 20W oil but would even go higher if it was available. 20W oil also increases compression damping which will help reduce dive under braking, but the real culprit is the spring and I would recommend you fit a stiffer spring. You have to take the fork caps off to fill with oil anyway, so it's no extra work to pull the spring out and fit a new one.
Another little trick is to slightly overfill the forks with oil. This reduces the amount of air in the forks and when they compress, the effective spring rate is increased. Try adding an extra 40ml of oil to each leg. Standard is 182ml, so 220ml should do it.
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Post by milkman on Dec 10, 2006 22:52:28 GMT -5
Not to alter the topic too much.....but my bike has air shokcs on teh front. The valve area says Daytona but the PO told me the forks are of an SRZ.
Anyway, I can't find the recommendatios for air pressure to equal what the equivalent would be in oil.
Can I just hand pump them gently until I feel they've reached a good level? I don't want to blow them out.
thanks. Shocks are a dark art to me
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Post by mildmitch on Dec 11, 2006 0:44:16 GMT -5
This is what I've heard. I have a set of air fittings I plan on fitting at a latter date. Hand pump ONLY! No Air Compressors.
Make them feel right to you and 5-8 psi max. Hope this is accurate as I don't have first hand experience. Hopefully someone else will chime in here.
Mitch
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Post by SRwillie on Dec 11, 2006 13:23:40 GMT -5
That's about right Mitch... One other thing, you need to use a low volume type gauge. On the 1976 YZ's that had the "Handgrenade" type accumulators on the fork, if you pumped in 12 ponuds and then checked the pressure, it may take 2-3 pounds away with the pressure to actuate the gauge. Not real critical on the road, but the MX guys really had a problem. An ATV specific gauge would probably work the best.
Thanks again for the Ebay seat transaction!
Willie
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Post by robomod on Dec 11, 2006 13:25:04 GMT -5
Hey Mitch- Are those air fittings hard to find?
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RD
Full Member
Posts: 176
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Post by RD on Dec 11, 2006 22:09:45 GMT -5
Hi guys
if you have air caps and need to play with the air in the forks go to a bicycle shop and pick up a mountain bike shock pump. They are high pressure but really low volume and they have a gauge mounted on them so are extremely accurate. Perfect for getting equal amounts of air in both sides, I wish I had one of these things in the eighties when all bikes came out with air adjustment on the suspension.
Cheers
Rich
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Post by colinjay on Dec 12, 2006 1:02:18 GMT -5
Hi all,
I am not sure if you can still buy them, but I have a "LINKO" brand syringe pump that was made especially for pressurising motorcycle front forks. I will admit that I bought it in the early 80's, hence why I am not sure if they are still on the market. What it is, is basically a 50ml syringe with a small low pressure 0 -15psi gauge fitted along with a bleed valve. The small volume output allow you too slowly increase the pressure, normally to a couple of psi above what you want, then using the bleed valve adjust the pressure down to the required setting.
CJ
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Post by mildmitch on Dec 12, 2006 1:08:18 GMT -5
Willie,
Good to see you here, Welcome aboard! That's a pretty nice seat too. I was going to tear into it to build up a Cafe seat/Tail, but can't bring myself to destroy it!
Robomod,
I found the set of air fittings on ebay. I actually bought them for my old Harley but may try them on the SR. It needs help more than the HD. I found them in the Harley listings. Every once in a while they show up there. I believe you can also do the same thing with regular brass fittings, and piece the set togetger.
I'll see what more I can find out about this for you.
Mitch
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Post by medic09 on Dec 19, 2006 21:08:39 GMT -5
These old style forks need thicker oil to effectively control rebound damping. I use 20W oil but would even go higher if it was available. 20W oil also increases compression damping which will help reduce dive under braking, but the real culprit is the spring and I would recommend you fit a stiffer spring. You have to take the fork caps off to fill with oil anyway, so it's no extra work to pull the spring out and fit a new one. Another little trick is to slightly overfill the forks with oil. This reduces the amount of air in the forks and when they compress, the effective spring rate is increased. Try adding an extra 40ml of oil to each leg. Standard is 182ml, so 220ml should do it. Okay, so here's a dumb novice question. Waited till now because I couldn't free the allen bolts to move the handlebars out of the way. So after a soak with Deep Creep, and applying a socketed allen head (had to buy that today), I've got the forks opened and drained. Remember folks, this is a first time, so be kind.  When I remove the fork caps, I have a spacer, then a little cap with a large hole in the center, then the spring. Do I just pour the proper amount of fork oil down the spring? BTW, even with a little pumping, I got only 150cc out of the fork. How much of the 182cc usually drains? I expected a little more, and so I'm thinking PO had these underfilled. Thanks! |
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Post by medic09 on Dec 19, 2006 21:15:42 GMT -5
Additional question:
the suggestion was to add some extra oil, if I like; say about 200cc total. The Clymer manual says not to add quantity, but to change the oil weight. What say you all?
Thanks!
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