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I have a 2003 crf 450r that I ride. When jumping big jumps I can hear the rear shock bottoming out. It has a stock rear shock on it. I weigh 205 and need to know where to buy a heavy spring for the shock. Have tuned the rebound and damping to max settings and it still bottoms out. If you know of part nos and places to buy the spring please let me know. Thanks.

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Springs are not really supposed to prevent you from bottoming out. That is what your valving is for. Your shock needs to be revalved for your riding style and weight.

Also, are you sure you're hearing the suspension bottom out, and not just clunking from worn linkage bearings?

Edited by Lead Head

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When was the last time the shock oil was serviced? When it gets a lot of hours on it, it breaks down and gets thinner, which makes it softer.

At 205, you could use stiffer springs. A set of .49kg fork springs and a 5.7kg rear spring should be just right. I'm 205-210 and that's what I've been running in all my CRF450's since 2004. You can get Race Tech springs in those rates through any dealer.

Don't just install a stiffer rear spring as it will throw the front/rear balance off. You need to do both ends at the same time.

Edited by CamP

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when you say rebound and damping to max settings, what exactly do you mean? All the way in on both? A rebuild is probably a good idea, or at least recharge the bladder, I'm sure after almost 10 years the pressure is low.

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Springs are not really supposed to prevent you from bottoming out. That is what your valving is for. Your shock needs to be revalved for your riding style and weight.

Also, are you sure you're hearing the suspension bottom out, and not just clunking from worn linkage bearings?

you have that so backwards. the spring rate is CRITICAL to the weight of the rider and helping from bottoming out.

If you use a spring for a 200# rider on a 150# rider it will never bottom. Reverse it and it will bottom ALL day long.

The shaft has a external bumpstop to help cushion the last few inches of travel.

Spring rate is for the weight. Valving is for speed/feeling/preference. You can use the same valving on a 150# rider as a 250# rider. You cannot with the spring.

racetech & mxtech both have spring rate calculators on their websites. Take a look at it there. As suggested once you get the proper springs FRONT and REAR install, a rebuild of the forks and shock with new fluids would be a very beneficial!

Edited by JJRace

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you have that so backwards. the spring rate is CRITICAL to the weight of the rider and helping from bottoming out.

1. If you use a spring for a 200# rider on a 150# rider it will never bottom.

2. Reverse it and it will bottom ALL day long.

3.The shaft has a external bumpstop to help cushion the last few inches of travel.

4.Spring rate is for the weight.

5.Valving is for speed/feeling/preference.

6.You can use the same valving on a 150# rider as a 250# rider.

7.You cannot with the spring.

racetech & mxtech both have spring rate calculators on their websites. Take a look at it there. As suggested once you get the proper springs FRONT and REAR install, a rebuild of the forks and shock with new fluids would be a very beneficial!

ahh...not really. The shock is far more responsible for controlling the bottoming than the spring. Even with the right springs you could bottom the suspension in the rear just by jumping up and down on the bike at a stand still if there was no shock involved.

Try it. If you do your own suspension, put the shock on the bike with no oil in it with no high speed adjuster in it either. Just oil the piston band up so it'll slide...throw the spring on it and put it in there, set the sag and then bounce on it....cherclunk...There's a reason the shock shafts are as big and as strong as they are. Lots and lots and lots of force on them.

1. Yes it will

2. Correct

3. Correct, but if that bump stop is hammered out, its going to give you a biblical clank at the bottom.

4. The spring rate sets the ride height with the proper load in reference to the position of the suspension. The rate is critical not just on collapse, but rebound as well. If you get the race sag set with too soft of a spring its going to top out and pogo when high in the stroke.

5. Correct

6. While you could, I doubt the 150lb guy is going to like the 200lb guys setup even with lighter springs. The rebound wouldnt function correctly most of the time.

7. I agree, correct again.

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+1 to shawn, if you put super light valving in with a heavy spring the 150lb guy will still bottom it out

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im quite positive if you put a stiff enough spring on a bike, mr. 150lb rider won't be able to bottom it out.. why would you ever do that? have no idea, and the ride would likely shake your teeth right out of your head but there is a spring stiff enough to keep from bottoming i will bet.

Sure sounds like as some have touched on there could be something as simple as the shock needing service, too worn linkage bearings (they will surely make a "clunk" if there is enough play). who knows, but the OP would benefit from posting lots more info as requested like when was the shock and linkage last serviced.

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CamP hit it right on the head with those spring rates. I to have a 03 & run same. I use factory connection springs front & rear. They have spring rate calculators on the website. A full service & fresh oil will help worlds as well if its been more than a year since last service. You might benifit from different valving depending on your skill level. A fast A class rider would. For most of us the stock valving on the 03 is or was pretty good & worked well with heavier springs.

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