22 replies to this topic

[curlylegend]

We're under house arrest here, again !   For at least a month, so I decided now was the time to do something about the seized damper adjusters on my 1991 TDM 850.

And I thought, while I'm at it, I might as well replace the bushings and fork seals.  So ordered the stuff up from Wemoto.fr  and made a start first thing this morning.

 

Firstly, I tackled the damper adjusters by Dremelling ( is that a word ? it ought to be ...)  out the pressed in washers at the top and finding that the adjustment wasn't equal. One adjuster was right out, up against the circlip, and the other one looks as if its wound right in.  

Dapleb  has put some excellent posts on here about this. To be honest, I don't think I would have tackled this job without them.

So both adjusters are steeping in penetrating fluid overnight and tomorrow I'll attempt to separate them and refurbish the detent springs and balls, using heat if necessary.

[attachment=13801:Electric Impact Wrench.jpg]

 

 

Next it was removing the bottom bolt holding in the damper tube. This, I've been well warned, can be stubborn.  I secured one of the fork legs onto my workbench and set about the bolt with a ferocious electric impact driver.  Did it remove it ?   Did it f*ck !!

OK. more super expensive penetrating fluid, then heat, then gave up and had a good sound fit of cursing.  That seemed to help and while my blood was up I started very carefully drilling out the head of the allen bolt. Once I'd got a 10 mm drill hole the head snapped off easily and I could remove the damper tube. 

I thought I was going to have a bit of a job getting the stub of the bolt out of the bottom of the damper but surprisingly I just ran it out with my fingers. No sign of Loctite ?

So why was the damn thing to tight ?

 

[attachment=13802:Drilled out Damper Bolt.jpg]

 

Then to remove the stanchion, bearing rings and seal.  I tried the Haynes method but all I was going to do with that was end up with arms like Popeye !  Dapleb to the rescue again with an article he'd done about making up a threaded puller arrangement.  I kind of modified his approach but the principle worked and I soon had the lot separated.

 

[attachment=13803:Dismantled Fork Leg.jpg]

 

That's the story so far. To be continued....

 

 

[itchyfeet2]

Dremelling.... defo a word.

 

Love these kind of posts on here, how long had you been riding the bike with the inconsistent adjustment? How did it handle?

[dablik]

Good job curly  but add one more weetabix at breakfast    mine came apart with the Haynes method and a little heat, it's doable.

[dapleb]

Well done that man.

Did the fork torture keep yer bushes from being mullered? Though I see you plan on replacing em anyways, just interested as that's why I used that method rather than Haynes, to save some known gooduns.

The bottom bolt, it wasn't just a case of the whole gubbins spinning? Normally summat required to wedge down the insoide to stop the innards from spinning. Yours was just not moving at all?

[curlylegend]

Dremelling.... defo a word.

 

Love these kind of posts on here, how long had you been riding the bike with the inconsistent adjustment? How did it handle?

 Been riding the bike for nearly three years now and once I'd changed the fork oil and put (more or less...) the right amount in it rode fairly well.  I'm using Dexron ATF at the moment. I'll wait and see if getting the damper adjusters working makes any difference before I start experimenting with different oils.

When I refill the oil this time, I'll do it properly and measure the level, not just put in a measured amount.

[curlylegend]

Good job curly  but add one more weetabix at breakfast    mine came apart with the Haynes method and a little heat, it's doable.

 

Unfortunately I can't eat Weetabix, or porridge or Shredded Wheat or stuff like that. And I'm a wimp nowadays.  I was leery about using heat, the only source I have is either boiling water or a gas torch. I didn't want to damage the paint any more than it is.    The bike is clean but definitely nearly thirty years old.  At the moment I can get away with it by extolling the "Patina, Dahling !"   If it gets much worse, I will have to think about a cosmetic refurb...

[curlylegend]

Well done that man.

Did the fork torture keep yer bushes from being mullered? Though I see you plan on replacing em anyways, just interested as that's why I used that method rather than Haynes, to save some known gooduns.

The bottom bolt, it wasn't just a case of the whole gubbins spinning? Normally summat required to wedge down the insoide to stop the innards from spinning. Yours was just not moving at all?

 I'll be able to tell you in a couple of days after I've done the other fork leg.  With this one, I'd started trying to dismantle it using the Haynes method, so although everything came out cleanly after a wee turn on the torture rack, there was some damage to the top bush, I think caused by my initial attempt.

And no, it wasn't a case of the bolt spinning, it was just solid, no movement whatsoever !  Yet once the head was drilled out everything came apart as neatly as you would like. Bit of a mystery.... and I'm not a fan of mysteries....

[dablik]

Check the bushes are the correct size when they arrive from Wemoto, they sent me the wrong size (smaller) by mistake but quickly amended for the correct ones.

[curlylegend]

Check the bushes are the correct size when they arrive from Wemoto, they sent me the wrong size (smaller) by mistake but quickly amended for the correct ones.

 

Did that, they're ok, thanks.

But ended up in a kind of grumpy mood this afternoon.  Despite a solid mornings work, I've failed miserably to get the damper adjusters separated.  They've been well soaked in penetrating fluid and I even used heat from a gas torch on them.  I've freed off aluminium components with heat before so I know to be canny with them.  The last thing I need is for the wee bastards to melt !   As you can see from the photo, they're pretty chewed up so there wasn't much to get a grip of.  

 

[attachment=13814:Front Damper Adjusters.jpg]

 

Ah weel !

 

I did at first think that they were unevenly adjusted, but now that I've got them well cleared out, by eye, there's not much of a difference in the gaps between the circlip ring and the top of the adjusters.  Using a digital depth gauge I'm only seeing a difference of 0.015mm  and measuring the depth from the face of the threaded section to the point where the damper adjuster rod abuts is similar...0.025. 

 

So unless anyone out there has any alternative solutions I'm going to have to use different oils to alter my damping characteristics..... bugger !

 

I must have done nearly 20,000 km since I last changed the fork oil and judging by the look of what came out this time, I'll be doing it much sooner in future.  When I last refilled the forks I measured a total of 395 ml for each leg but what I drained out was a good bit less than that.  The seals were good and there are no other leaks, so where did the oil go ?   

Curious ?

 

So still waiting for replacement bottom bolts and a get out of jail card from our President before I can do any testing.

[Bjørge]

What about installing a set of fork valves (like gold valves), after installing those you have no use for damping adjustment. And they improve suspension vastly

[dapleb]

I'm sure they are... but little circlips out curly?

There are spaces atwix inner adjuster and main body (where ball bearing sits) that collect crud, these need thorough cleaning and soaking to get everything freed up. Don't give up on freeing them off yet as long as you can remain patient with em!

[curlylegend]

What about installing a set of fork valves (like gold valves), after installing those you have no use for damping adjustment. And they improve suspension vastly

 

I am considering this option, but is it not a bit of a faff setting them up ?   Don't forget, I'm really quite a lazy sod !

 

I'm sure they are... but little circlips out curly?

There are spaces atwix inner adjuster and main body (where ball bearing sits) that collect crud, these need thorough cleaning and soaking to get everything freed up. Don't give up on freeing them off yet as long as you can remain patient with em!

 

Yes, the circlips are out and I suppose the only other option with these is to soak them for as long as it takes.  That would be ok, but I don't want to have my TDM marooned in the garage for any longer than necessary.  I might start searching for a couple of spares if I don't take up Bjørge's suggestion.

 

You asked whether the bushes were damaged after pulling them out.  Here's a couple of pics.  You can see that the bottom bush has been forced into the top teflon lined bush and scrubbed off the teflon coating.  So I suppose it's not a guaranteed method of removing the top bush without damage.

 

[attachment=13815:Bottom Fork Bush.jpg]

 

[attachment=13816:Top Fork Bush.jpg]

 

And here's some photos of my Torture Rack. Just an old Black and Decker work bench with some threaded rod that was lying about. I placed a couple of alloy sections at the other end to prevent the fork leg digging into the wooden bench top.

 

[attachment=13817:Torture Rack.jpg]

 

[attachment=13818:Totrure Rack 1.jpg]

 

An absolute scoop to use !

[Bjørge]

 
I am considering this option, but is it not a bit of a faff setting them up ?   Don't forget, I'm really quite a lazy sod !
 

Not really hard work, as I recall... you decide what profile you want and install the valve and the shim stack to go with the chosen setup. Oil viscosity, too. You won't look back.

[dapleb]

Ferry noice torture devoice!

What does your threaded bar go to inside the toob?

I don't think I have any spare adjusters which is a bigger else could do an exchange program. Will look.

[Studley Ramrod]

I wonder if the mk2 wans will fit ?  https://www.gn-moto....-1996-2001.html

[dablik]

I wonder if the mk2 wans will fit ?  https://www.gn-moto....-1996-2001.html

 

Mk2 forks 43mm Ian..

[Studley Ramrod]

True, but I think the diameter of the adjusters are the same, if ya get me drift.

[dablik]

True, but I think the diameter of the adjusters are the same, if ya get me drift.

 

Gotcha, be good if they do..

[curlylegend]

Ferry noice torture devoice!

What does your threaded bar go to inside the toob?

I don't think I have any spare adjusters which is a bigger else could do an exchange program. Will look.

[attachment=13823:Stepped Washer.jpg]

 

Just the stepped washer from the  top of the spring and a couple of smaller washers.

 

I wonder if the mk2 wans will fit ?  https://www.gn-moto....-1996-2001.html

I had a good look at them and at that price nearly bought them !   But on closer inspection it looks like the damper rod on the Mk2 is a sort of push fit into the damper adjuster, not threaded like the Mk 1. Whether the damper adjuster from the Mk2 could be modified to take the threaded Mk1 damper rod, I don't know ?

 

 

Gotcha, be good if they do..

Sure would, but it would be a bit of a waste of money if they didn't work, especially if that money could go towards a set of Race Tech Gold Valves. Definitely a case where you'd love to be able to hold the damn things in your hand to check them out !

[curlylegend]

Not really hard work, as I recall... you decide what profile you want and install the valve and the shim stack to go with the chosen setup. Oil viscosity, too. You won't look back.

 

I had a look at Race Tech's site but found it very American and therefore super technical but very similar to directions you get from Microsoft or Apple. I unfortunately couldn't recognise anything resembling my TDM forks.  I've no doubt that their instructions are perfectly correct and with my level of ignorance about the intricacies of motorcycle suspension I certainly wouldn't criticise them. 

I would very much appreciate someone to walk me through the process, as it were, to see if this is something I am capable of doing.   For example what exactly should I be buying ?  And from where ?  Race Tech direct ?

Am I correct in assuming that to make the adjustments I don't need to completely dismantle the forks again ?