Mk1 suspension improvement

Well I finally got all the Race Tech stuff necessary for a front fork revalving and spent an afternoon rebuilding the forks. My '95 3VD has now 0.85 kg/mm linear front springs and Gold Valves shimmed according to RT's recommendations. The instructions were pretty general and I doubt they've field tested a rare beast like the TDM very thoroughly. After pulling the damper assembly apart installing the gold valves was pretty straightforward.
I took photos along the way. I'm sorry they are huge but I don't know how to compress them without loosing too much of the quality.

Gold Valves and shims This is just about all there was in the Gold Valve package (instructions and stickers aren't shown). The paper is a printed copy of the Digital Valving Search results.

Here are the the Gold Valves. Notice the hole you have to drill through them. Mine was 1.3mm.

After removing the allen bolt at the bottom of the forks the damper assembly should come out. The compression valve is at the bottom of the damper assembly but I removed the rebound piston (together with the damper rod) too to clean everything thoroughly. The compression piston and damper rod sleeve were fastened with Loctite to the damper tube so I had to use heat to get them off.

Here's the original compression piston. There are no bending shims, just the valve and a thick shim that acts as a oneway valve. The damping is created only by the original valve.

The Gold Valve uses a shim stack to control the damping. The Gold Valve sits on top of the shim stack, then there's a larger shim held down by a spring that acts as a oneway valve. Here's the complete compression piston with Gold Valves, and an another picture.

I used 15W fork oil just as RT recommended. The first impressions of the suspension were mixed. It was absolutely brilliant when hitting large bumps, I could easily ride over a speed bump without slowing down at all, the front just glides over them with no shocks at the bars whatsoever. But it was a lot harsher than original when going over small holes or cracks in the road. Maybe I wasn't pushing it hard enough, I've only ridden a few hundread km's this spring and the engine is still being broken in after a rebuild. But still it seems too stiff and I don't feel confident at all when hitting rough tarmac while leaned over. I think it's mostly becouse of too much rebound damping, the Gold Valves don't affect the rebound but the 15W oil does. Even with the external adjusters all the way out it seems too stiff.
Adjusting the damn things is a pain, You have to pull the forks completely apart just to adjust them. I think I'll try the easy way first and change to 10W oil. It should soften the rebound damping and hopefully compression too.

Fantastic, thank you for taking the time to write that up and take pics Stink-Foot.

I have added the info to the 'Depository' suspension section: http://www.carpe-tdm...p?showtopic=382

Cheers
dapleb

coolio, excellent write up and pics.

Yes indeed... now if I just knew what the feck it al meant.....

Mechanically challenged but I have a good and fairly reasonable mechanic.

Excellent stinky.................and final proof that the Mk1s have a superior cartridge type set up to the feeble attempt at damping on the Mk2 and 900

If you look at my WEBSITE there's kinda basic writeup of the conversion to the Mk2 and 900s, that one you've done is great

Definitely go for 10W oil stinky - it won't affect the compression damping but it'll make all the difference to the rebound Allow for the extra volume taken up by the gold Valves - in other words, use less oil and you'll have a smoother ride (more air)



Oh, and by the way.......I thought it was a very interesting article on Finnish trains in your newspaper

Edited by dandywarhol, 19 April 2006 - 12:33 am.

They might be better than on the Mk2 or 900 but still not very good. Makes me wonder why Kayaba didn't make them decent to begin with. The "bending shims" kind of valve seems to work so much better. It can't be becouse of the costs, how much would a few thin shims cost? Only thing I can think of is that a fixed hole size valve is more robust, any crap between the shims in a gold valve would affect it's action.



Errmm.. Are You thinking of the GV emulators? The actual Gold Valves don't take up any more volume than the originals. But I believe You're right about lowering the oil level. I didn't even check up the original oil level from Haynes, just blindly followed RT's recommendations. I'll try 10W oil next weekend and play with the levels a bit. I e-mailed Race Tech once again about adjustments but they never seem to answer. From what I've heard they're helpful over the phone but I'm not gonna call long distance across the world in the middle of the night and try to explain the problem in my crappy English..



You weren't paying attention! The article wasn't about trains but people getting run over by them .

Yes , oops


It's much better than my crappy Finnish

as dandy said u can really change the fork action by upping or lowering the oil level.on a mk2 i think the measurement is 120mm from fork leg top 2 oil but i ended up with 135mm 2 suit my preference.have you set the sag on your bike? it made a lot of difference 2 mine.

Thanks. I'll try lowering the oil level. I set the sag to 35mm but I think I'll decrease it too a little. Since the compression damping is now really effective the bike doesn't dive as much as before.

I'm still sitting at 35mm with my 900 but just removed 50cc of oil the other day having ridden the mannie's 960 last weekend - not nearly as harsh now on uneven road repairs and still damping good

Edited by dandywarhol, 21 April 2006 - 12:33 am.

Trains, Waiting for trains, Getting run over by trains....

When I was about to change the fork oil a week ago I noticed a fork seal leaking just a bit. I thought it wouldn't take more than a few hours to change them since the forks would have to come off anyway so I went out and got a pair of from a dealer.

Well first thing was getting the outer fork tubes separated from the inner tubes to remove the old seals. One came off easily but the other one was really stuck. I had to use some brute force, unfortunately it ruined the teflon coating on fork slides. Of course the finnish importer didn't have them in stock.
The new slides finally arrived today. I was in a rush to get back on the bike so I started right away. When ever I try to hurry when working on bikes or cars I end up doing something stupid. Today was no exception. The bike was supported by a rear stand and a jack under the exhaust. I had trouble getting the front wheel axle to go through the wheel so I tapped it with a piece of wood. I was planning on giving it just a gentle knock, but when it didn't help I hit it a bit harder... and the whole bike fell over . Broken mirror, bent clutch lever, a deep cut in my forefinger, loud cursing and tools flying around. Hopefully the fork tubes or brake discs werent bent, guess I'll see after the test ride tomorrow.

Moral of the story? Try to think before You act when doing anything with a motorcycle, whether riding it and repairing it.
Oh and if it has anything to do with the forks, pay someone else to do it!

At least you didn't get squashed Stinky, then it would really be a bad day. There is a Stunt Monkey section for those of us prone to the odd mishap!

Cheers
dapleb

Did the same on my last bike stinky, watched it wobble a bit then fell over.........baassad

I took the bike for a 200km blast through the back roads and some gravel roads too today. Small country roads are in a really poor condition after the winter but the suspension worked extremely well.
Changing the oil from 15W to 10W made a huge difference, now the front wheel follows the roads even when driving over small potholes or such. I also lowered the level of the oil by 10mm. I set the sag at 40mm which seems to allow enough movement both ways.

Sounds like you've got it sussed stinky..................still looking into that Arctic/Ruskie tour................might see the fruits of your work in July

On a similar note, I had a go on Emmetts 850 with Ohlins rear and was impressed............it really makes a HUGE difference over stock

Edited by dandywarhol, 28 April 2006 - 06:15 pm.

Just got back from a loooonnnnggg trip Alan, and the setup was spot on, even two 1200gs riders were impressed with the suspension on the 850

Edited by Emmett, 30 April 2006 - 03:17 pm.