3he fork questions

[JohnBoy69]

Hi,

Got 'round to doing the fork seals on my '90 3he restoration, and before i get new oil in to finish the forks I have a couple of questions.

My forks may have been modded but I found each leg had a large washer underneath the spring with a hole in it and the springs were upside down compared to the haynes manual i that mine had the tight coils at the bottom and not the top.

Have these things been done for a reason- stiffness perhaps? I'm guessing the washers are to restrict oil flow and stiffen the travel?- Good idea to leave them or take them out?

What is the concensus on oil to use- standard 10w/synthetic 10w?? I'm about 10.5 stone, and I'm not gonna ride the bike very hard- too scared...

Cheers,

John

[sweekster]

My guess would be the same as yours. Your weight(10.5 stone) should translate to around 150lbs (or 68kgs) and if memory serves that's what the forks were engineered with in mind. Still relative in my opinion. 10w should be fine. This is more of a preference call. I ran 30w in my old 600 with stock springs. I have 20w in the 1k with more preload added. Again my preference.

[fzrbrandon]

Regarding which direction the springs go in - I don't think it matters much since the compression is the same whether your going top to bottom or vice versa (it's the same force from either direction). However, given the choice, I'd be inclined to just put them in the way the manual says to put them in.

[DonTZ125]

There was some discussion a while back about which coil winding should be up; comments were made regarding unsprung weight and trapped air volume, but I honestly can't see that it would make a huge amount of difference.

[JohnBoy69]

Thanks guys.

Any opinions on the washers?

[yamaha_george]

Hi,
Ok , lets get the basics out of the way.
The more spring metal in the oil will make the air gap (read air spring) smaller since the oil level is set BEFORE the springs are put in place.Thus the air spring will be stiffer.
The reverse is also true.

As to the washer that was used as a method of slowing the oil out of the top of the damper rod , you did not strip the forks right down but it may be the damper rods had been modified for "emulators" or PD Valves but removed when the bike was sold (since they are an expensive(ish) item }the washers were put in place to act as flow restrictors since the damper rods would now flow far to much oil and VERY quickly.

To get an idea as to what this is all about (modded dampers,PD valves) look at :-

http://www.saltmine.org.uk/fzr/fork.html

Has i hope some good pictures of the "bits" and a how to make on making your own proper fork tools for the FZR


HTH

[JohnBoy69]

Thanks GEO- great info

I did strip them down and the springs and damper rods are standard and not modified.

Waiting on some oil from ebay before putting them back on, and i think i'll leave the washers in.

I'd read the guides first and managed to cobble together my own holding 'tool' using parts from a household rad lockvalve, 12mm allen drive bit into that, then socket on that and 3/8th drive extension into adapter and then two 1/2" drive extensions- Heath Robinson would have approved!!

Cheers,

John

[yamaha_george]

Thanks GEO- great info

I did strip them down and the springs and damper rods are standard and not modified.

Waiting on some oil from ebay before putting them back on, and i think i'll leave the washers in.

I'd read the guides first and managed to cobble together my own holding 'tool' using parts from a household rad lockvalve, 12mm allen drive bit into that, then socket on that and 3/8th drive extension into adapter and then two 1/2" drive extensions- Heath Robinson would have approved!!

Cheers,

John

John,
H-R would definitely approve but it worked is the main thing.

I have used extensions before and had one "disconnect" on me and then the very messy job of removing the faulty part as it had decided to mate intimately with the damper rod hence the oath (after several and varied Anglo-saxon outbursts) never to do it again without a proper tool. Now I have set of double-ended tools for all my bikes :-}