Spension first

[wurlyvalve]

Hello all,

I bought a few days ago a third hand TRX. It came with a lot of history but there are still a few blanks and unknowns that this forums search feature hasn't completely satisfied for me. Whilst I can ask the ex-owner questions, he didn't know anything about the mods made to the bike, he was a rider not a tinkerer.

If I could ask a few questions..... the bike sits high. Very high. It's about 40degrees on its side stand. I'm 6'1" and my feet can't touch the ground. And from the 'reviews' I was expecting bouncy suspension - this is like a rock, it makes my wifes' GSXR feel exeedingly compliant.

Rear suspension.
The spring is yellow - I guess they coated with different colours for styling only? Is there an easy way to check if it is a TRX coil over damper or R6? There is a remote damping adjuster (goldish in coating). Spring length maybe?
The rear rocker arm? Is there an easy way to identify which flavour that is?
The are a pair of rear dogbones in the box of bits that I have been handed by the ex-TRX owner. They are the original ones. I have 3GM dogbones on the bike, I think that is an EXUP part (FZR1000). They are approx 11/16" shorter than the originals. Which by my hands (I live away from home during the week and don't even have a yard stick for measuring) for dodgy guesstimating linkage rates equates to about a 1.5" lift.?.
When I sit on her, my flabby RS seems to compress the seat about 3/8". I'm about 14st.
Setting "4" on the preload lugs.

Front suspension.
The forks are black. The stanchions protrude a whisker over 11/16" above the yoke. There are 5 annular grooves exposed. Rebound only adjust (I think). I think they are std but not sure about the internals. And I'm infinitely too lazy to take them apart to check. So I would guess I will never know until I have to fix them.

Any hints for checking would be very helpful,
Cheers,
Glen.

[phuk72]

from your description, I would guess (photos would really help) that you have standard suspension and that the rear has been jacked up by chaging the dog bones.

i'm also guessing that the suspension is fecked - it will be over 15 years old and most people (stupidly) never bother with the suspension.

so you have 2 choices:

1 - live with it (and maybe buy an r1 sidestand which is longer)

or 2 - get off you lazy arse and start twiddling. As a minimum, i would be changign the fork oil and then (trying to) set the sag.

There is loads of info on here but feel free to ask qestions

[M.V.]

Yellow spring with gold resovoir sounds like stock TRX - dogbones would account for the jacking up at the rear.

At the front end, sound like the forks aren't dropped through the yokes enough - IIRC there should 18.5mm of stanchion protruding above the clip on clamp.

Pics would help of course.

Take it back to stock & work from there.

[alextrx850]

Ipswich, Glen..is that in the UK ?
Interesting you are using inches and stones in units of measure.

[wurlyvalve]

On its sidestand.

[wurlyvalve]

Front forks.

[wurlyvalve]

Top yokes, fork poke through.

[wurlyvalve]

Dogbones/rocker linkage.

[wurlyvalve]

Coil over damper.

[wurlyvalve]

Remote adjuster.

[wurlyvalve]

Yep. UK. We in England use imperial. I think the younger ones have switched to French - I mean metric.

[cobbadiggabuddyblooo]

For a reference / starting point . Place the std dogbones back on to give you a std trx starting / reference point. Rear spring rate std is for a .85 -75kg rider and front std are .7 - 65kg rider if my memory serves me right and as Alex mentioned sit the forks through to standard exposed length above the clip on.
Leave the preload on the front and rear spring and try setting position3 on the 4 position front rebound . there is 180* turn between position4 to start again at position 1.
Try about 15 clicks clockwise on the rear gold compression adjuster. ( 20 click adjustment on rear)
Check rebound on the bottom of rear shock.
Wind it clockwise till it stops. Like your screwing something in.
Push on the back of the bike and should rebound really slow.
Wind out 8 clicks of the 20 click rebound adjuster and now push on the front and the rear of the bike at the same time and check both ends of the bike are rebounding about the same .
Std front is a 120/60 so check front tyre profile. If a 120/70 expose around 5 more mm to accomidate the extra tyre profile height.
Check your tyre pressures and most run 32-34 front and 36-38 rear.
Now you have a starting point .
Check you have about 20mm play on the drive chain at its tightest point and the wheel is set central via adjustment marks.
See how it feel when you sit on it now .
Go for a short ride 5-10 minutes.
See how it feels .

Now as puck said. Read up on how to set the sag and once you have done that..
Go for another ride ..
See if you have some improvements each time you you have gone through these basic set up points.
Write down the current suspension setting,and how it feels to ride..
Then write down the basic ones I have suggested and your feedback on how it feels .
Eg. How it feels under brakes and turns into corners,
How it feels as you roll on the throttle out of corners
How it feels travelling over bumps.

compare notes to the first 2 options after setting the sag and tweak the rebound first if need be then compression 2 or 3 clicks to to your feel but jot down any changes so if your not happy go back to the previous setting again and try something else.



For a reference on cheap options...
Fork oil ..
Costs about $200 to rebuild your std rear shock and around $100 to respring to your weight.
Cost about $150 to respring the front to your weight.
Some go for an later model R6 rear shock with an adaptor to suit the Trx length and attachment.
For about the same cost to rebuilt the std rear shock which is quite adequate for most once sprung to your weight.
R6 shock has a slightly heavier spring buy .05 but not really enough for your weight and its valving is set up for a R6 rising rate suspension with a longer swingarm length and different relay arm.
So to get the most from an r6 shock you really need to rebuild it and respring it anyhow so costs begin to grow all up and close to the price of a basic aftermarket replacement shock new.

Std dogbone length 182mm centre to centre.
Yzf 750 dogbone. 172mm centre to centre

[Kayla]

Yep. UK. We in England use imperial. I think the younger ones have switched to French - I mean metric.

We used to the use Imperial system back, well, back when we had an empire FFS, measure a metric bike in metric!

The standard dogbones are 182mm long, 3GM ones are 165mm long which is way too short, which is why your rear suspension feels way too stiff. To do it on the cheap, and this is entirely subjective, a 20mm lift (177mm dogbones) at the rear is coupled with a 20mm drop at the front. This keeps the ride height close to standard but alters the attitude of the bike (the rake is reduced from 25 degrees to around 24 which helps sharpen it up without leaving it too slappy).

[cobbadiggabuddyblooo]

Personally I have exactly as Kayla said before my rebuild with 5mm shorter dogbones ( 177mm), and front dropped a little further and it is a pretty balanced outcome as she said.
I first tried just changing to 10 mm shorter yzf750 dogbone(172mm) , lifting only the rear and not changing the front to get it to turn in faster but it made it feel a little flighty on faster sweeping corners.
As Kayla mentioned if you make slight adjustments in the front and rear and not just the rear alone you can find find a better balance to give you the best outcome when changing the geometry of your bike.

[wurlyvalve]

OK. I, personally, didn't make an adjustment to the rear only. I actually thought I had bought a std (suspension) bike. Only after riding it (having ridden for 23years) I realised straight away that something was afoot with the stiffness.

I guess you are referring to an extra 20mm on top of the std 18mm (yoke poke)? So a net pitch change of 40mm over the wheelbase?

Yep, std 120/60/431.8 at the front - I'm slowly selling off my Whitworth sockets to friend at work, so I am changing to keep up with the times. (Which is the friendly paking the tiss emoticon?)

Hmm. Maybe I should trust nothing and start afresh as you've listed below. It doesn't corner badly. But I guess if an extra short dogbone has been fitted I should assume nothing! Thanks for the breakdown. That is a super good guide. I will follow that And I think the 177mm/20mm pitch change too as per Kayla and Cobba.

Not wishing to extend my laziness beyond tolerable limits, is an ebay 177mm dogbone a good source? Do you buy motorbike springs like one buys race car springs? ie, just spec spring rate, free length and id?

Cheers,
Glen.