1970 fork rebuild

the-oz-slider · Dec 31, 2010

Hello all, I'm sure this topic has ben dealt with before so maybe someone can give me the link please.

Long story short I have a 1970 XS1 , engine #000290. Its complete but with a few non standard parts, but with the help of some great guys off the forum I am slowly getting it back to all original stock condition.
Thing is it handles like an absolutely-mindless-drug-addled-runaway-14-year-old-hooker [there- did I offend enough minority groups??]...so I started at the rear and bought new shocks, new F & R Dunlop TT100 tyres, needle roller swing arm bearins, roller steering bearins, new wheel bearins front and rear and now I am at the forks.
While Im at it what can I do to improve the fork action????
Bike will be near concours when Im finished, but I also want it to handle OK.....
Suggestions please!!
the-oz-slider

royxxx · Dec 31, 2010

fit Progressive springs & experiment with different weights of oil.

ReycleBill · Dec 31, 2010

Also, a stout fender and/or fork brace.

yamasarus · Dec 31, 2010

Oz,
The XS1 fork is pretty archaic. I made mine a little better by switching to internal springs. The 71 springs fit, but so will the 73 springs, which is what I went with. I still run the boots and nobody knows. I went with a 15 weight oil at 8 oz. per tube. I haven't put much time on the bike yet, but it seem to be comfortable at regular speeds. Always keep in mind the the 70-73 models don't really want to turn in if you push them.
Oh, one last thing. Install Bridgestone Spitfire S11s if you want it to handle it's best. Dunlop K70s are correct, but are awful. A tire that was born in the 60s.

:bike:

the-oz-slider · Jan 1, 2011

The tyres are TT100's not k70's....I wouldnt fit K70's to a Vokshod, much less this bike........then again they'd probably help the Vokshod a lot :laugh:

I went with the TT's for the period look, have never seen the bridgestones up here....
The internal spring issue looks good, as I have a good set of '72 forks sitting in my workshop that have progressive springs in them.....now thats got me thinkin' :doh:

Keep the input and opinions coming....we have about 3' of snow on the ground so I have lots of time to contemplate what to do.....
Thanks one and all...
the-oz-slider

XSLeo · Jan 1, 2011

Making the two piece front engine mount a one piece will stiffen the front up a bit Adding some bracing by the swing arm pivot will stiffen the rear some. Adding a cross brace at the top of the rear shocks Will help.

scobman · Jan 22, 2011

Switch out the xs1 forks and use xs1b forks instead.
I could trade ya.
or I could get the xs1 forks off ya and help you fund getting a different pair of whatever your going to get.

yamasarus · Jan 22, 2011

Scob,
That would be pointless. The XS1 and 1B have the same front forks except for the external versus internal springs and gaitors versus dust covers.

scobman · Jan 22, 2011

Not exactly, they are quite different my friend.
xs1b & xs1 outer tubes are different.
xs1 outer tubes are straight, xs1b outer tubes have little wings at the bottom with bolt holes.
different mixture of inner parts

scobman · Jan 22, 2011

PLUS, .......... The FORK EARS are also different for the XS1 and XS1B FORKS.
XS1 fork ears are tapered, XS1B fork ears are straight. And the lower fork ear guides are different, they are larger to fit the tapered bottom end of the fork ears.

scobman · Jan 22, 2011

My xs2

My XS1B

Start of my XS1

yamasarus · Jan 22, 2011

This thread was about making the XS1 forks handle better, but to your point. You are splitting hairs. Yes the tabs were added as production continued. The headlite stays from 70 to 73 all interchange(per Yamaha part number). The differences in internal parts are to support the differerence in springs.

scobman · Jan 23, 2011

Oh my bad,
I thought the question was about improving the front suspension/forks on the xs1 bike for a better smoother ride.
I misunderstood the question was about improving the xs1 forks.
Still I'd say to improve the xs1 forks if they arent providing that snug tight front suspension handling, replace them with xs1b forks. Just put the gaitor boots on instead of the dust caps.

Or maybe, if keeping the bike original isnt your main goal, custom install some tire air valves thru the center of the fork cap bolts.

Then pump them up with a little more air.

Your bikes look very nice.
Your xs1 doesnt have the original xs1 headlight stays.
Your right, the headlight stays 70-73 are interchangable, but the original 1970 oem yamaha xs1 headlight stays are tappered and are a bigger diameter on the bottom. The lower headlight stay guides are a bigger diameter and the fork trims are GIANT compared to the little fork trims on the xs1b & xs2.

Parts are parts and they all work, but to be oem original on the xs1, the forks and the tappered headlight stays with giant stay guides and giant fork trims make the difference. Plus they ring up the value of the bike.
........... But you can use the xs1b or xs2 stays and paint them candy green and put the gaitor boots on the xs1b forks and only a few intense people will notice.
I have a good teacher, Mark Tomlinson - marks650yamahas

scobman · Jan 23, 2011

But its all good,
maybe 1 day ill get my bikes to look as nice as yours.

yamasarus · Jan 23, 2011

You are still missing the point. The forks are the same except for the springs. You could put internal springs in a 70 front end by adding the seat and spacer. It would then work just like a 71 front end because everything else is the same mechanically. You can also make your own spacer to soften or stiffen the front forks once the springs are internal.
And yes, my headlight stays are from a 73. But you didn't comment on the color. I hate the stock green so mine is two shades darker. It still does quite well in shows, but with the fork modifications it really rides much better. Everything was done by me except chrome. There are many, many differences between a 70 and 71 and mine has been upgraded where ever possible to make it a better bike. Afterall, I built it for me to ride. Attached is the before picture, but it was a 70 and therefore worth saving.
I have to apologize. My only training was 15 years as a Yamaha parts manager and another 20 years working on Yamahas........
But it's all good.

scobman · Jan 23, 2011

I guess my ideology is set on restorations to the original oem build.

I understand a rider like you would want to improve your bikes to ride better.

I wont be riding my bikes except to maybe bike shows.
So its not that important to me how the forks feel on my bikes at 100mph because thats not what Ive built them for.

But to be technical about it, there are parts involved in the xs1 forks that the xs1b forks dont have.
The xs1 forks are about the rarest assembly amoung all the parts involved in the 1970-1973 xs/tx650s bikes.

I have that collectors blood in me, Im not really a rider so I guess thats where we seeing things differently.

1973 tx650 triple tree and crown are wider than the xs1/xs1b/xs2 triple tree and crown so those shouldnt be inter mixed or you might crash.

To me it doesnt matter if I like the candy green color or not, thats just the color it is so thats what I want.

But I do LIKE the darker green you have on your bike.
I bet you look a lot sharper riding down the street when you pull up next to a guy on a 30k store bought 2010 Harley who doesnt know an allen wrench from a socket.

My xs2 has 5k original miles on it and my mother bought it new for my dad on my 1st birthday. So once that bike is fully restored it will never reach 6k miles.

pyroman · Jan 23, 2011

Scobman, please dont lump all Harley Riders into that worn out cliche. I own Harleys, and other bikes and I do 95% of My own work. There are similar trains of thought on Guys who show their bikes, but dont ride them, but I am not going to go there. All bikes are good. Except Chinese. :wink2:

scobman · Jan 23, 2011

I wasnt lumping them all together, its just some of them Im talking about and you know which ones I mean.
Mostly the wall street banker types I was referring to. lol
Spending their billion dollar bonuses.

Id like to see the guys from OCC actually build a motor for once, wouldnt you?

pyroman · Jan 23, 2011

scobman said:
I wasnt lumping them all together, its just some of them Im talking about and you know which ones I mean.
Mostly the wall street banker types I was referring to. lol
Spending their billion dollar bonuses.

Id like to see the guys from OCC actually build a motor for once, wouldnt you?

My collar is very blue, with grease stains. :wink2:

The OCC Guys have a hard time just putting one in a frame, and getting it started..... :wtf:

scobman · Jan 23, 2011

lolol,
yea thats what Im saying.
All they do is cut/weld and fabricate sheet metal to make fenders, exhausts and gas tanks on cookie cutter bikes.

Even my little weiner dog has a little bit of grease on him.

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