Jump to content
Sign in to follow this  

valving question

Recommended Posts

I just bought 450 that was setup for a 160lbs. and I'm 205lbs.I put the recommended springs in,my question is,is the valving that much different for 45lbs.difference in body weight.I went up 2 rates in the front and three maybe 4 in the rear.I rode the bike and it feels really good.If the previous rider was the same skill level and everything else was the same except body weight would there be a big difference in shim stacks?

Share this post


Link to post
Share on other sites

if you ask a suspension tuner,they will say yes and try to sell you a revalve.if the bike is balanced and feels good to you,then roost on.peace and wheelies!!!

Share this post


Link to post
Share on other sites

The "rule of thumb" is that you change springs to adjust to your weight, and change the valving to adjust to your skill and style.

Keeping in mind that everything can be improved (sometimes dramatically), if you have made the necessary spring changes and the bike feels OK to you, handles well, isn't too harsh or too mushy, then you should probably run it as is. If it gives you some kind of problem related to the suspension behavior, then some work may be of benefit to you.

It's a cost/benefit question. Yes, it most likely (almost certainly) can be improved, but will it be worth it to you? In regard to the question you are asking, which seems to be whether the valve must be changed to accommodate a change in rider weight, the answer is probably not.

Share this post


Link to post
Share on other sites

My gut tells me to leave it alone,the suspension feels great.my tuner tells me I need to revalve.My only complaint is that the forks bottomed on me hard a couple times last week so I tried to add 10cc of oil.

Share this post


Link to post
Share on other sites

Tried comp.2 clicks harder front and back and felt like bike didn't settle into the track as well but that seemed to fix the bottoming issue,so that's when I decided to go back 2 clicks to the baseline settings add oil.I haven't tried it since adding the oil.I'm very impressed with the suspension on this bike compared to my 07 crf450 and that was revalved for me by the same guy.

Share this post


Link to post
Share on other sites

The '09 uses a KYB fork much like the YZ450. With regards to bottoming, you can do these things:

Clamp down some more on the compression adjusters (on the top). This may not work all that well given you tried that but backed off of it because it had unwanted side effects.

Raise the oil level. The downside is that the fork can rather quickly become harsh.

Use a heavier oil in the outer chamber. This actually works quite well. The outer chamber oil only does two things, which are to lube the fork telescoping assembly, and to provide bottoming resistance by means of the oil locks at the bottom. It has no effect on damping otherwise. The oil locks are simply a system by which the space available for the oil to flow around the bottom end of the internal cartridge as it moves downward in the fork is reduced in the last 30mm or so of travel. Since this is what amounts to a fixed orifice through which oil is forced, using a heavier oil will provide increased flow resistance, and thus better bottoming braking. If you are currently using a 5wt, go to a 7wt. If using a 3wt use a 5. Just be sure the two oils are a compatible formula, as they will eventually become mixed as oil is forced past the rod seals into the inner chamber.

Failing that, heavier springs or a change in compression valving may be necessary.

Share this post


Link to post
Share on other sites

thats exactly what i was thinking,grayracer must be a mind reader.lol.were the fork springs you put in the right ones for your weight?

Share this post


Link to post
Share on other sites
thats exactly what i was thinking,grayracer must be a mind reader.lol.were the fork springs you put in the right ones for your weight?

Yeah,I'm 205 without gear and went with .49's and a 5.7.I already put 10cc of oil in and haven't ridden yet because im in the n.east and my track closed for the year.I will test the higher oil when I get a chance and if that doesn't work I will do what grayracer suggested with the oil wt.I have maxima 5wt. in there and will try the 7wt.If I don't get the desired results from oil height and wt. might just leave it because it not bad at all,Thanx guys.

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

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×