Rear Shock Adjustment Question

Anybody know what this adjustment is for and what each setting is?


I was checking to see if the spring I have off of another bike would fit, and noticed the adjustment. Turns rather easily with a screwdriver.

This is the spring I have, looks like it may be too heavy for a lighter person such as myself.

Its rebound shock absorber hydraulic damping adjustment. Citing manual here:

Hi mag00.
Is there any information stamped on the shock spring giving indication to the springs rate, kg/mm example 6.8

The adjustment is rebound ( only ) and does actually make a difference. If you reduce the preload you also need to reduce the damping but not linearly. The rebound is primarily to control the spring rate which does not change by changing the preload but can assist with control top out at ride height and full extention.
You can't tell spring rate just by looking especially if the springs are different colours ( lighter colours look fatter). Both coils have the same number of coils but the red one looks like the coil diameter is wider so if the overall spring length is the same and they are the same diameter, the red one will have longer wire so will be softer.
You need to measure the wire diameter, the total number of coils ( including the not complete turns), the overall coil diameter and the free length. There are a heap of spring calculators on the net. That should get you a ball park figure for the spring rates.
The red one looks like it is a wider internal diameter as well so prob won't sit on the top collet and the bottom seat properly. You may have to make a set of spacers.
If you don't have the stuff, honestly, just go to a motorcycle suspension ( phone, email whatever). One place where you get real enthusiasts is suspension places. Occasionally you get an arrogant prick, but mostly they actually want to really get it right for you. If you are noteably different in weight to what the bike is designed for then a correct suspension setup is one of the best things you can do. It will change how you feel about your ride unless you are a numb arse rider ( IE it all feels the same to me).
Personally, I think the shock is not a particularly good one anyway. Doesn't handle square bumps well at all. An aftermarket shock and spring tuned for you will change the bike. If you are lighter or heavier than about 75/80kg ( about 180lbs) then a change of shock/spring and fork springs will probably be well worth it. Next to an exhaust change to reduce the weight and a booster plug ( or equivalent), this is the next most useful change you can make top the bike. HOWEVER read not cheap if you are getting a shock as well as the springs ( springs are not too expensive, but labour to instal may be high if you can't do it yourself)

That's the Holy - - Shit adjuster.
Your good, I would not move it any more towards the Shit side.

Thanks for that info. I am planning to take the shock in and have both springs tested. The red one I am sure is shorter, as it is the same length unsprung as the Terra one is assembled. No worry, as I have plenty of adjustment to take up the shortness and get some preload.

I thought about buying those fire damaged shocks on ebay, but the chrome is pitted pretty bad, so probably not much good to rebuild.

Front does not seem too bad, it is a bit clunky/clumsy though.

Nothing I could find on either spring.

Thanks mag00.
I am going to take the bike to a local suspension specialist (Terry Hays , Shock Treatment).
He has done a couple of TR650.
I am getting the appropriate shock spring for my weight and a re valve.
I find out what the original spring weight is whilst I am there.
I am booked in for Friday 22nd..
In a couple of weeks I will go back and get the front end done.
Until till then, cheers.
Craig

Good move Biff. He knows his stuff. I found him a bit rude but he really does know his stuff.

Shit, all you Aussie's are having your suspensions done, lucky dogs....

They are down under so the suspension upgrade hasn't floated to the top yet. Cheers guys and have a great weekend. Oh and a beer or your favorite choice of beverage.

Bumpy, since we are talking rear shocks...

Has anyone any ideas how to 'easily' adjust the spring pre-load on the rear shock, I have tried but just cant get my hand in there with the tool to do it.
My thoughts were - Have they caught the B****** that designed this set up, but then again I am sure it was the same guy who designed the air filter access and the inner spark plug fitting as well as the throttle body.... pretty sure he is on a beach somewhere reading this forum and laughing his a*se off.

Be sure to use the spark plug socket as a handle for the spanner. Still a bitch, but just checking that your at least doing that.

Big blade screwdriver + hammer. Easy. . Start gently & work your way up in force.

Here is where my rear shock is set. Which way do I need to go in order to reduce front end wobble?

Going clockwise is increasing the preload, that should help with the wobble. Just go one notch at a time, and try

Sorry, but I think you want to decrease the preload to try to fix the wobble.
Your goal is to lower the back of the bike.