Lowering Bike Sag??

[yammieman]

ok so. I have a 04 YZ250 2 stroke that i can't fully reach the ground on when on the bike(im on my tipy toes). I would like to know how to check sag and also how to adjust it if neccessary.
I cannot find in the manual what the factory specs are so i was hoping someone could chime in on that one.
I am 5'9" and weight around 60kg's and use the bike for trail/forest riding.
Would I need to turn the spring clockwise(right) or anti clockwise(left) to adjust it to make it lower? i only need about an inch lower to be able to touch the ground fully.
and also, would the specs be located under "wheel travel"?

 

[High Lord Gomer]

You first need to loosen the lower nut below the spring. There are two that tighten to lock against each other. Loosen the bottom one and get it down an in or so to get it out of the way. The can then loosing the other low one by twisting the spring clockwise. The remaining lower nut will spin with the spring and will lessen the pre-load on the spring by allowing it to expand more. I would suggest doing all of this with the bike on a stand and the rear wheel / swingarm lowered all the way. You should not need to lower the spring preload much to lower the bike.

Measure the distance from the seat bolt to the rear axle bolt with the rear wheel off the ground. Then measure the distance from the seat bolt to the axle both with the bike upright on both wheels without rider. The difference between the first and second measurements is called static sag.

Next, measure the distance from the seat bolt to the axle bolt with you on the bike in full gear in your normal riding position. Best to have someone else measure this for you while you lightly balance yourself next to a wall in the proper position. The difference between this third measurement and the second measurement is called race sag.

There have been people for more knowledgeable than me discuss recommendations for these in the Suspension sub-forum. In general, an inch or so of static sag and 3.5-4 inches of race sag is normal.

 

[yammieman]

ok thanks mate. will go do my measurements. am i meant to be turning the spring left or right to lower/loosen it?

 

[_JOE_]

The two spring nuts should be on top of the spring. They're standard thread so counterclockwise to loosen the top one then counterclockwise on the lower one to take preload off of the spring and lower the bike.

 

[RM_guy]

If you lower the back end with the spring sag adjustment and the sag is more than 105 mm you will adversely affect the handling. It won't turn very well and the forks will feel too stiff.

You can offset it by raising the forks up in the triple clamps but I doubt you can compensate for 1" lower in the back end.

The only way to lower the bike as much as you want is to have the suspension modified along with lowering the sub frame. It's not a cheap thing to do.

 

[High Lord Gomer]

The two spring nuts should be on top of the spring. They're standard thread so counterclockwise to loosen the top one then counterclockwise on the lower one to take preload off of the spring and lower the bike.

Wow...has it been *that* long since I did it?

 

[_JOE_]

Good point RM guy. I think that's where Gomer was going with the static sag thing. You need to keep both static and loaded sag within the limits. If the bike is too tall shaving the seat foam is probably the best thing to do. Followed by suspension mods. I can only tip toe with one foot on a full size bike, but that doesn't bother me. As soon as the bike starts to move your feet should be on the pegs anyway. Some people just seem to get so hung up on not being able to touch the ground. The way I see it is, you shouldn't be reaching for the ground unless the bike is falling. At that point it's alot closer to the ground than when you're sitting on it not moving. Don't screw up the safety of your bike at speed for more comfort sitting still. It's a dirt bike, not a chair! ;)

 

[rmc_olderthandirt]

As others have said, adjusting the sag to lower seat height is not the best approach. If you are 5' 9" tall, I would think that the normal height would be perfect for you. tippy toes is fine, you don't need both feet flat on the ground.

If you are intent on lowering the bike, check out this link:

http://www.koubalink.com/

They sell a new link arm that connects between the rear shock and the swing arm that results in the suspension being lowered without changing the sag. It does change the leverage, so the resulting spring rate is less, but you are fairly light so that probably won't be an issue.

My daughter is 5' 2" and used one to lower her bike. 1-/2 inches on the rear, dropped the forks in the clamp and inch (had to raise the handlebars to make room), cut 1" off the seat foam. It is working great for her.

A tip on adjusting the sag: use a long punch and hammer to back off the lock nut. I bought a special tool that was supposed to be for that but there wasn't room to use it!

To adjust the nut that is tight against the spring it is often easier to grab the spring and turn it. "most" of the time the nut will turn with the spring. I have had that method fail, however. In this case, use the punch to drive the main nut.

The direction you need to go should be obvious. Squeezng the spring tighter raises things up.

Rod