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Bottoming Out Fork

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Got the 450x out on the track for the first time last week. I found it amazingly nimble for such a big bike. My only complaint was that I was bottoming the fork on some of the big stuff. I had the compression clickers 5 clicks from the hardest setting.

I weigh 190-195 with gear.

Based on your experience, should I consider oil height and clickers, or do I definitely need stronger springs?

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To determine what springs you need, you need to set your race sag, and go from there.

If you still have the stock oil, it only lasts about one year then goes bad.

It's time to replace it.

At 195lbs, you are right on the verge of needing springs.

Bottoming out has nothing to do with springs however.

That is all in the dampening.

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I also went to the track with mine last weekend and it's definitely amazing for an enduro! But the fork bottom out at every big jump even with the clicker maxed out and I'm only 130 pounds..

So I checked on Race Tech website and found out we got the exact same fork as 07 crf450r except with 360cc of oil instead of 375, and with less stiff pressure springs, fork springs are the same. I then ordered 450r pressure springs and will put 380cc of oil and try it at the track next weekend.

Hopefully this will solve the issue and stop beating my ass every time I land

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I also went to the track with mine last weekend and it's definitely amazing for an enduro! But the fork bottom out at every big jump even with the clicker maxed out and I'm only 130 pounds..

So I checked on Race Tech website and found out we got the exact same fork as 07 crf450r except with 360cc of oil instead of 375, and with less stiff pressure springs, fork springs are the same. I then ordered 450r pressure springs and will put 380cc of oil and try it at the track next weekend.

Hopefully this will solve the issue and stop beating my ass every time I land

While your information about the R vs X forks is correct, that is not the whole story.

The R fork has thicker tubes for less flex, and a completely different shim stack and valve setting. Both are for refined turning on track conditions.

Adding stiffer fork springs will raise the bike up in the stroke, increasing overall fork travel. It will make the bike feel softer, because you are no longer riding in the firm part of the stroke, but it will do very little to prevent bottoming.

Changing the pressure springs to R springs only effects the first 3" of fork travel, and will make your forks more harsh. Most people here on TT go to softer pressure springs than stock X so the bike will ride smoother in the hacky stuff.

Oil height is there to increase or decrease the compression of the air cavity in the fork. Raising in increases compression, lowering it softens compression.

The R fork has lower oil height because it's damping is much more aggressive, and does not need the extra air-compression. If you lower the oil in your X forks, it will bottom more, not less.

Changing the fork springs without changing the dampening to match will have some positive and some negative results. Especially in the rebound dampening, because now it has to push against more tension.

If you want to bottom less, you need revalve the forks and put in better oil.

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Thanks, will start with an oil change. I just bought the bike in the fall but my guess is that the fork oil has never been changed.

Are there any fork oil alternatives that I can pick up at the auto parts store for convenience sake?

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I don't know where in VA you are located but I was having the same problems, in fact I blew both seals after tooling around on a small track. I decided to go to Heavy Duty Racing in Stafford, they use MX tech suspension. Pete (hes on the forum) was super nice, and did a great job about a 10 day turnaround. I weigh 220 with gear so he re-valved and re-sprung the front and put a stiffer spring on in the rear for what I thought was a fairly good price. I set the sag on on it this Sunday, and went to the same track and it was night and day, the same landings that blew my fork seals were nice and soft and did not come close to bottoming out.

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I'm in Fairfax County up close to DC. I had Pete do a crank for my old RM250 rebuild last year. Great service and nice guy. I'm going to put some fresh oil in and play with the height and clickers and see where that gets me.

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