Anyone pick up a 450FX yet?

Rmk, your saying you have more static sag with a stiffer spring? Opposit of what I would have thought, I'm about your size 185-190, I had sag set at 100 because I read that somewhere that's what worked best on the 450f, couldn't find anything on the fx. The bike works great in sand whoops but a bit stiff in rocks & roots, lowering in would be helpful in the technical, I'm 6' and am on my toes on flat ground.

Before I did this, I asked the same question.  I figured if you went to a stiffer spring it would make the static sag less and it would push the rear end even more up.  I was told by many that is not the case, because you take out the pre-load and when you sit on the bike its plush and not that pre-load harshness.   They were all right, when I put in a stiffer spring, I don't have that preload and the bike dropped.  I would definitely consider putting in the 5.8 if your around my weight and drop those forks 4mm.  ... When you sit your sag to 100, what was your static sag?  If your less then 20mm, I would go the the next stiffer spring.   The bike felt so much better.

Before I did this, I asked the same question.  I figured if you went to a stiffer spring it would make the static sag less and it would push the rear end even more up.  I was told by many that is not the case, because you take out the pre-load and when you sit on the bike its plush and not that pre-load harshness.   They were all right, when I put in a stiffer spring, I don't have that preload and the bike dropped.  I would definitely consider putting in the 5.8 if your around my weight and drop those forks 4mm.  ... When you sit your sag to 100, what was your static sag?  If your less then 20mm, I would go the the next stiffer spring.   The bike felt so much better.

With 100mm of sag I have 23mm of static sag.

I guess that makes sense, do you know off hand what weight range the stock springs for? 165-175?

 

Not for certain, although with the 450's it seems to be in the range of 175-195 (street clothes)

I believe the stock spring is a 5.6 which is the same as the F... But keep in mind the FX is about 20lbs heavier so the stock springs on the FX seem to be for a 160-180 lb rider.

I'm 255 and couldn't get close to the right numbers with a 6.3. At 110 race sag I was at like 21 static sag. My 6.8 should be here Monday. Can't wait to try it!

I saw a pic on Facebook of a magazine test bike, I think it was Dirt Rider, and the tank they used actually eliminated the stock rad shrouds and those were part of the tank.  Not much to my liking so I was hoping there was a more sleek option out there.  2.5 gallons would be perfect for me.

Now to email the wife again to negotiate more so I can put a 450FX in the garage...

 

The IMS 2.5 is available in dry break only but there in an option for a cap adapter. It uses stock shrouds. Only a small seat mod is required for it. Photo courtesy of IMS.

If you like this tank you could Email Daniel at IMS and he'll hook you up. I think they'll be available in a couple/three weeks.

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Edited by cubera

I believe the stock spring is a 5.6 which is the same as the F... But keep in mind the FX is about 20lbs heavier so the stock springs on the FX seem to be for a 160-180 lb rider.

 

Stock springs on the 450FX are .44/5.4

 

Edit: I stand corrected. 450FX springs are .45/5.6

Edited by cubera

I'm 255 and couldn't get close to the right numbers with a 6.3. At 110 race sag I was at like 21 static sag. My 6.8 should be here Monday. Can't wait to try it!

 

I'm 240# and have no problems with a 6.0 at 24/106.

The IMS 2.5 is available in dry break only but there in an option for a cap adapter. It uses stock shrouds. Only a small seat mod is required for it. Photo courtesy of IMS.

If you like this tank you could Email Daniel at IMS and he'll hook you up. I think they'll be available in a couple/three weeks.

 

I'm curious how or if that tank is different than the one for the 450F.  Forgive my ignorance, I'm still in the research mode and arguing with my wife over why I need to buy a new bike.  I even wrote a lengthy and articulated letter explaining in excruciating detail why I need a 450FX but still no joy...

I'm 240# and have no problems with a 6.0 at 24/106.

That's a pretty low static number. Personally I'd rather have less preload than more preload for off-road use. I bet a 6.3 or 6.6 would be perfect. Do you check your sag standing or sitting?

I'm curious how or if that tank is different than the one for the 450F. Forgive my ignorance, I'm still in the research mode and arguing with my wife over why I need to buy a new bike. I even wrote a lengthy and articulated letter explaining in excruciating detail why I need a 450FX but still no joy...

Yes, it is smaller at the back due to the FX battery...

That's a pretty low static number. Personally I'd rather have less preload than more preload for off-road use. I bet a 6.3 or 6.6 would be perfect. Do you check your sag standing or sitting?

 

Low static sag? You're kidding right? It's in range albeit on the low side and I'll bet is has changed after some pounding today. I think it'll do. Race sag can be checked either sitting or standing so long as all the rider's weight is directly over CG. People should measure it up on the pegs in attack position and sitting with weight forward on the seat to see how much, if any, difference there is. Take the larger number of the two.

Edited by cubera

That's a pretty low static number. Personally I'd rather have less preload than more preload for off-road use. I bet a 6.3 or 6.6 would be perfect. Do you check your sag standing or sitting?

 

 

I'm 255 and couldn't get close to the right numbers with a 6.3. At 110 race sag I was at like 21 static sag. My 6.8 should be here Monday. Can't wait to try it!

 

21mm is acceptable for static sag but 110mm race sag is a bit much unless you're racing in sand.

Ahh... Dirt rider said they come with 4.5/56. I assumed they knew what they' were talking about.

http://www.dirtrider.com/2016-yamaha-yz450fx-first-test

 

I stand corrected. Dirt Rider April 2016 edition p26. FX is .45/5.6 while YZ is .50/5.6. I was off by 0.01N/mm on the forks. I'm running .50/6.0 on the FX and these spring rates are good for my weight, terrain, and skill for now especially with Precision Concepts valving.

Edited by cubera

21mm is acceptable for static sag but 110mm race sag is a bit much unless you're racing in sand.

Myself and a lot of others guys are finding the FX likes a lot of race sag, like 110 to 112.

Even Jimmy Lewis is using that number. I find most of my Yamahas are the same. Maybe not so much if you change the fork preload and modify internals.

Perfect. My personal preference is 105-110 closer to 105 on the 450 and 110 on 250.

The IMS 2.5 is available in dry break only but there in an option for a cap adapter. It uses stock shrouds. Only a small seat mod is required for it. Photo courtesy of IMS.

If you like this tank you could Email Daniel at IMS and he'll hook you up. I think they'll be available in a couple/three weeks.

 

I think you will find you have the relocate the battery and electronics for the FX to run this tank.

Not according to IMS. Only a minor mod to the seat is required. Per IMS.

Not according to IMS. Only a minor mod to the seat is required. Per IMS.

 

If it fits with the battery and electronics the small seat cover needs to disappear. I think I also heard that it doesn't accept the fitting for the reserve light unless maybe they are making it for the FX and WR.

 

Acerbis is suppose to be coming out with a little bigger tank for the WR250 and that should fit the 450's.

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