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Evo 2009 4T Rear Shock Sag!


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#1 jfc

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Posted 15 April 2012 - 06:45 PM

Hi all

I have been using the bike from new with the rear sag set as it came from the shop.
After reading lots on set up and finding it all very complicated I left it set as was to avoid loosing its good grip (if it isn't broken, don't fix it).

I have now gripped the nettle and checked the sag, it was nearly 50% of the rear travel!
So I have now set it to 1/3 of its travel as described here http://www.Gas Gas.c...nsion-tips.html

The rear of the bike is now much more active and easier to hop, but I am concerned that I may now loose grip more easily or have other problems.
Will I now have to re-learn how to ride the bike or should it improve my riding?

Any thoughts would be more than welcome.

John

Edited by JFC, 15 April 2012 - 06:49 PM.



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#2 joekarter

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Posted 15 April 2012 - 07:32 PM

Hi all

I have been using the bike from new with the rear sag set as it came from the shop.
After reading lots on set up and finding it all very complicated I left it set as was to avoid loosing its good grip (if it isn't broken, don't fix it).

I have now gripped the nettle and checked the sag, it was nearly 50% of the rear travel!
So I have now set it to 1/3 of its travel as described here http://www.Gas Gas.c...nsion-tips.html

The rear of the bike is now much more active and easier to hop, but I am concerned that I may now loose grip more easily or have other problems.
Will I now have to re-learn how to ride the bike or should it improve my riding?

Any thoughts would be more than welcome.

John


Two questions:

How much do you weigh with your gear on?

Does the bike have any free sag at all with the "1/3 of it's travel" setup?

#3 jfc

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Posted 15 April 2012 - 07:37 PM

90 KG

By free sag do you mean sag with no weight on the bike, if so it has no free sag!

#4 pindie

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Posted 15 April 2012 - 08:08 PM

You need a teeny bit of "free" or static sag. I may be wrong but try and wind the spripg back so you get 15-20mm static sag.

You are right though, by adding tension to your spring it makes the bike much more lively.

I tweaked a mates 1999 TXT 270 today by winding up the speing tension - he is over the moon, literally! Before it was totally dead and lifeless Now it is zebedy.

Remember one rule though.

ALWAYS RIGHT DOWN WHAT YOU MOVE AND BY HOW MUCH!

If you don't you can't put it back to what you knew before.

Edited by pindie, 15 April 2012 - 08:09 PM.

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#5 nzralphy

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Posted 16 April 2012 - 07:50 AM

Setting the sag to 1/3 is exactly right.

Rebound damping gives you traction. Fast rebound makes the bike hop quickly but the quicker it hops up.... the quicker the rear tyre looses traction.

Now you have to set the rebound damping so that the action is not super bouncy.... just take the edge off the action and you can sense it is getting slower. Try it. The adjust it and try it again.

Ralphy
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#6 jfc

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Posted 16 April 2012 - 05:56 PM

Ralphy

What about the free sag! do i need any as posted above, I want to get this set the best I can!

John

#7 pindie

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Posted 16 April 2012 - 08:29 PM

I think with linkless systems i.e. Beta Rev 3 it is crucial to have the right static or free sag.

Mines doen by eye,feel and rough measurements for my weight etc.

I've not found any listed setting yet on the web.
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#8 jfc

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Posted 16 April 2012 - 08:35 PM

Thanks for your time and the info,
Just noticed you are talking about rev 3, the evo is a linkage system with dog bone linkage!

#9 nzralphy

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Posted 17 April 2012 - 09:17 AM

Linkage or no linkage follow the same suspension rules.

2009 and 2010 Beta Evos had soft springs (god knows what the factory were smoking?)..... so unless you are 65 - 70kg you'll likely need a heavier spring.

Free sag is tough to get right with a trials bike as they are sooooooo light. So I generally don't panic over this so much (if at all).

Anyway set you static sag with you stood on the bike in riding gear. Get a friend to help. Measure it a few times to get an average.

Step off the bike and the bike shouldn't snap up to the top of it's travel. Ideally it will be 10-20mm sagged under its own weight. If it goes right up to the top - the spring is too soft........ or if it has WAY too much free sag - the spring is likely to be too stiff for you (yes I know this sounds backwards but it is true).

Also if the static sag has been set correctly and you bottom the bike too often (assuming the damper is working correctly) then the spring is too soft.

......Saunders does a heavier spring

Edited by NZRalphy, 17 April 2012 - 09:27 AM.

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#10 nzralphy

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Posted 17 April 2012 - 09:32 AM

Have you adjusted the midrange jetting on your bike?

The 4Ts are shipped from the factory running lean to pass emissions testing. If you raise the needle the bike has a much stronger smoother mid range.
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#11 jfc

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Posted 17 April 2012 - 08:34 PM

No I have not, on inspection of the sparkplug it is all ways dry sooty black in colours (possibly misleading me into thinking it is running rich) I did drop the needle to lean it off but did not like the outcome, It is now back as shipped.
With the plug running black is it wise to lift the needle?
The shock is now set with 5mm free sag and just over 1/3 race sag, I have adjusted the rebound damping just enough to take the edge off the rebound and slow things down slightly.
I will need to give it some riding time to see how it feels as I have only been on the driveway.

#12 nzralphy

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Posted 18 April 2012 - 09:17 AM

Don't panic about the colour of the plug. Mine runs so black it is scary. Raise the needle. The bike loves the richer midrange and will run so much better. Some guys lift it and use 2nd from the bottom notch but i've set mine on bottom clip position and get a much better hill climber.

Happy riding.
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