Jump to content
Sign in to follow this  

Honda crf450r Spring rates

Recommended Posts

Hello mates, 

My name is Nick I have honda crf450r 2008 ,I bought this bike second hand before 2 years ago .  I need advice to choose fork and shock spring rates , my weight is 90 kg (198 lbs)with all my motocross clothes.When I start jumping frond and rear fenders touch in tires. I try in racetech calculator and it gives me forks 0,50 shock 5,8 . In the manual on honda standard are 0,47-5,4 for rider between 150-160 lbs. I asked K-tech they recommend me forks 0,44 shock 5,25 . Another suspension company said me the stock are good for my weight. 

I need properly advice ,I don't know which advice is correct 

Share this post


Link to post
Share on other sites

Keep tech own chart says std rear 5.5 which I bet gives you decent sag numbers but I would step up one rate in forks

Share this post


Link to post
Share on other sites

What you mean to keep standard springs just front 1 up rate 0,48? I can post the picture and you will see the fenders hit in tires front and rear and that is small jump 1,5 m high

Share this post


Link to post
Share on other sites

Keep Std rear (assuming it gives good free and race sag ) and go up on the front one rate , it's not unusual to see black marks (depending on how severe ) but it's not the springs that stop bottoming , it's a function of oil valving, air gap and spring rate

Share this post


Link to post
Share on other sites

Hello mates, 

My name is Nick I have honda crf450r 2008 ,I bought this bike second hand before 2 years ago .  I need advice to choose spring rates , my weight is 90 kg (198 lbs)with all my motocross clothes.When I start jumping frond and rear fenders touch in tires. I try in racetech calculator and it gives me forks 0,50 shock 5,8 . In the manual on honda standard are 0,47-5,4 for rider between 150-160 lbs. I asked K-tech they recommend me forks 0,44 shock 5,25 . Another suspension company said me the stock are good for my weight. 

I need properly advice ,I don't know which advice is correct 

 

0.44 would be silly.

first of all you need a full rebuild fresh fluid, just go ahead and buy seals and bushings as well.

I would go with the 0.50 fork springs.

and try setting your sag to 100mm and see what you get for free sag on the rear.

Edited by EnglertRacing

Share this post


Link to post
Share on other sites

i suggest 0.49 on front and 5.7 on rear , i have same frame and 250cc enginw , im 90kg and i use 5.5 and 0.48  ,when i was riding 450cc i using suggested spring

Share this post


Link to post
Share on other sites

Thanks mates for advice. I'm mechanic and I will rebuild myself, but I don't understand to much from suspension setting . Now I'm in London and my bike is in Bulgaria , my father sent me forks and rear shock. I will send my springs to "Revs Suspension" they will measure and they will  tell me correct spring rates. They gave me forks 0,48 shock 5,6 for my weight 90 kg , but I don't know, I think that is soft from small jump 1,5 m high and they touch fenders another gays jumping 3-4 meter high and all is ok .I checked my shock spring is stock because hasn't mark . 

Share this post


Link to post
Share on other sites

As I said springs will not stop bottoming , they set the ride height

Share this post


Link to post
Share on other sites

Ok , can I adjust stock valve or I need change with gold valve?

Share this post


Link to post
Share on other sites

Thanks mate, could you explain how ? If you want I can give you e-mail or skype for more easy.

Share this post


Link to post
Share on other sites

Sorry for stupid question ,next week I will open my forks and I will check spring rates and valve stack index,After I need advice .

Thank you mates :smashpc:  

Share this post


Link to post
Share on other sites

Hello mates, I open my forks and check how is setting, The spring someone maybe changed because the marks are deleted , the Oil was 320-330cc . I open the base valve the valve stack is :

 

14 x 31

4 x 30

3 x 29

2 x 28

27

26

25

24

23

22

20

18

16

 

 

I think nobody before me touch the valve stack, because I opened for first time the nut . Also the big spring next base valve is moving 2-3 mm is that normal or I need Adjust. What do you think the valve stack is ok ?And when open the nut do you change with different, how need to blocked the valve nut?

Share this post


Link to post
Share on other sites

The reason your bottoming is the oil level , you can run upto 380cc but normally 360cc, if you want to stiffen it remove the 16mm bottom shim, it will stiffen the entire stack a reasonable amount , also get your springs tested as they could be way soft?

Share this post


Link to post
Share on other sites

Have you installed normal nut with plastic lock on the base valve? I put and I am not sure it will be safety

Share this post


Link to post
Share on other sites

Try to undo it and see how easy it is , at the correct torque even a plain nut is not likely to come undone

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×