Two Stroke Motocross
Two Stroke Motocross Forum => Technical => Topic started by: thepope on April 02, 2011, 01:25:10 PM
-
Hello there! so i was looking at my 05 yz 250 and was about to check the race sag and stuff. and i came to a conclusion that i needed a stiffer spring. time goes by and i was pondering on the race sag and such.. and i said to my self.. -HEY! if my race sag was 115mm and my static sag was 36 .. then perhaps i dont need a stiffer spring?
if i adjust the rear shock 10mm i would have 26 static sag and 105 race sag right?
Or am i way to tired to understand the simple maths, or unwilling to spend more money on my bike, so i have to find a cheaper solution to get my bike prepped and ready to go before the season starts.
Sorry for bad english :)
-
You're likely not far off.Set your race sag to 100mm and recheck your static.If you're 25mm or thereabouts,you're good to go.
-
If I were to set my race sag to 100mm on my KX250 it would have so much head shake it would be impossible to ride.
Your race sag should be between 105 and 120mm, depending on the track conditions, the lower number for tighter stuff and the higher number for faster more open courses. Less race sag will steepen the rake on your steering making the bike turn faster, while more will lengthen the rake and make the bike more stable at speed.
And to answer your question, YES, you currently have too much preload on the spring. Loosen the lock ring, and take a few turns out until you get it to 105mm. Then re measure your Static it should be right on the money.
-
25mm(1 in) static sag and 100mm(4 in) race sag is where it should be.If you have to go less than about 95 or more than about 105 you should look at getting a different spring.
If you have to go 120mm mcclung you're chasing a geometry or other set up issue.Maybe you need a pro circuit link or drop the front end in the clamps.The pope has a YZ and 25/100 is good,and the accepted norm.However,that's a bike that's engineered and executed properly.The same can't be said for all the other manufacturers :P ;)
-
thanks for clearing that up :) oh yeah.. havnt been riding dirtbike since 2003 and that was a 1993 yamaha yz 125. it was abit slower than a 05 yz 250 :)
But how much should the top end at the clamps drop at a rough sandy track? i dont remember right but its over 15mm down i think..
-
Ha Ha, Duh Ford, it is an 07 KX250 ;),the forks ARE flush with the clamps. Pro Circuit doesn't have the link in stock, and they don't have any plans to produce more, I can't find anyone who does stock it. I had my suspension guru valve the shock knowing about the extra 10- 15mm of sag and the spring being 1 rate stiffer for my weight, it's real good now.
If you can find one even used, send me a link, I will sell a kidney if I have to.
-
thanks for clearing that up :) oh yeah.. havnt been riding dirtbike since 2003 and that was a 1993 yamaha yz 125. it was abit slower than a 05 yz 250 :)
But how much should the top end at the clamps drop at a rough sandy track? i dont remember right but its over 15mm down i think..
Personally,once I have my suspension working well,I leave the fork position alone for everything.A little less compression front and rear for the woods but that's about the only deviation I make for conditions-sand,mud or hardpack.On the other hand,I hate sandtracks :D
-
Ha Ha, Duh Ford, it is an 07 KX250 ;),the forks ARE flush with the clamps. Pro Circuit doesn't have the link in stock, and they don't have any plans to produce more, I can't find anyone who does stock it. I had my suspension guru valve the shock knowing about the extra 10- 15mm of sag and the spring being 1 rate stiffer for my weight, it's real good now.
If you can find one even used, send me a link, I will sell a kidney if I have to.
A YZ don't need no stinkin' aftermarket link to work properly ;D ;)
I'll keep an eye out for you around here to see if one turns up.
-
if i may borow this thred for a question? i hawe a honda cr 125 tunder by srs. how mutch race sag should i have? and so on? greatfull for awnsers!
-
if i may borow this thred for a question? i hawe a honda cr 125 tunder by srs. how mutch race sag should i have? and so on? greatfull for awnsers!
as a genral rule, all mx bikes should be around 25mm static sag and 100mm race sag when your sat on the bike. And for the guy running 120mm rear race sag, have you tried harder forks? maybe they are diving too much?
-
the problem with the 2003 up KX's, is solely due to frame geometry, Kawasaki took almost 2 degrees of rake from the head tube when they redesigned the KX line for 2003. This took away the formerly super stable feel the earlier KX models were famous for. The rear shocks also have a very fast rising rate that it not easily controllable at the rebound clickers with the stock valving. It adds to the stink bug feel and makes the rear end want to ride too high in the stroke. So to compensate for the steep rake the back of the bike needs to be lowered to add rake to the front end. Pro Circuit accomplished this with a 3mm longer link. it lowers the rear end almost an inch feeding rake into the front end and changing the rising rate of the shock to a more acceptable speed. I accomplished this task simply by adding an extra 10 mm of sag. I must also add that the rear spring is .1 kg heavier than ideal for my weight and I had the shock revalved for off road to accommidate the extra 10mm of sag. Works great.
-
if i got 28mm free sag and 90mm static sag do i need a softer spring then?
-
if i got 28mm free sag and 90mm static sag do i need a softer spring then?
Your about on the limit, you could try setting free sag at 25 and if you get 95 static then it should be good, but talk to a suspension guy if your unsure, but your not massivley out :)
-
then i need to compress the spring and then i wil gett around 80mm race sag? less free sag less racesag?
-
then i need to compress the spring and then i wil gett around 80mm race sag? less free sag less racesag?
Sorry, I meant to say set 30 ish and try and get 95, you should get a happy medium somewhere very close to perfect
-
ok thanks. but there is one more thing. is the rear suspension supose to bottom out?
-
No, it should never bottom out, within reason, on my shock it has bottom out controll, but thats a fox podium, but if you set the sag up first, then play with the clickers to fine tune it you should get it working good
-
ok how is the fork supose to behave? my kyb cartride is a bitt soft i thing hos is the sag on them?
-
Its really difficult to measure sag on the front forks theres a lot of sticktion on them when your stood still, so its best to talk to a suspension guy and see if your body weight needs a harder/softer spring
-
Ha Ha, Duh Ford, it is an 07 KX250 ;),the forks ARE flush with the clamps. Pro Circuit doesn't have the link in stock, and they don't have any plans to produce more, I can't find anyone who does stock it. I had my suspension guru valve the shock knowing about the extra 10- 15mm of sag and the spring being 1 rate stiffer for my weight, it's real good now.
If you can find one even used, send me a link, I will sell a kidney if I have to.
Have you tried ordering lately? I bought my PC linkage back in Sept 10' for a 2006 kx 250.
-
No I haven't. But I'll pass on it. Since I had the suspension re valved, and installed the proper rate fork springs for my weight. It is now the best handling bike I have ever ridden in the conditions I ride. I reset the sag to 110mm (from 115mm) as it was feeling a little sluggish turning in the tight stuff since the fork no longer dives going into turns. This took a little getting used to for sweepers with Ginormous brake/acceleration mounds at the apex but it became second nature after a few miles. 8)
-
No I haven't. But I'll pass on it. Since I had the suspension re valved, and installed the proper rate fork springs for my weight. It is now the best handling bike I have ever ridden in the conditions I ride. I reset the sag to 110mm (from 115mm) as it was feeling a little sluggish turning in the tight stuff since the fork no longer dives going into turns. This took a little getting used to for sweepers with Ginormous brake/acceleration mounds at the apex but it became second nature after a few miles. 8)
Awesome! Good to hear that you have it dialed. Happy moto's!