yz fork and shock interchange

No, it doesn't hit.....where it was in the first picture is about as close as it gets. I can push it farther away about 1/4 inch. The top shock bearing is going to limit any radial movement...no matter on the stand or at full compression. Moving thru the stroke, the shock does move fore or aft, but it splays out (a word?) during compression..... moving even farther away from the frame.

Clear as mud?

I'm going to attempt to break these options down into a digestible form:

Your options depend on how dedicated you are to keeping the YZ400, and after that, what condition the current fork is in. There is very little to be gained by changing forks from what you have to any alternative other than the '06 or later. The '05 can be made to work as well as the '06, but it takes time and money. The '06 fork will cost you less than rebuilding yours with the Race Tech kit, and while you won't learn as much that way, the stock '06 will be a much better setup.

But let me float this one: If you really don't want to spend that much on it, either just rebuild yours as they are, or...

Clean it up, sell it, and buy an '06 running and ready. You can get one for as little as $2k these days, and if all you can get for yours is $800, that's a hell of an upgrade for a $1200 net.

moto2000 so you're saying that the 2007 shock might very well fit my bike?

Did you experience a noticable improvement with that shock vs. the stock one?

That depends on how much clearance you are comfortable with.

If you already have an '07 shock I'd say yes, but install it on your bike without the spring and move the swingarm through the full length of its travel. If you can keep at least a quarter inch of clearance around the shock body I'd say your golden. If it's less than a quarter inch, I would be concerned. The frame will bend and deflect as you hit things and that eighth inch may dwindle to nothing under dynamic loads.

If you don't already have a shock in hand, personnaly, I would feel more confident using a shock from a steel frame bike. But that all depends on price. If you can get an '07 or later shock for really cheap, it might be woth the risk. The ony functional difference between the '05 YZ shock and the '07 is a little more oil volume.

Thanks for all the input guys.

I called race tech yesterday to order parts for my forks and shock. I decided just to do a refreshing of the OE parts. Maybe at a later time I can upgrade to the gold valves, but right now its just not feasible. The price for all the seals, bushings, heads, oil, and a few special tools ran up to almost $400 before shipping...I just can't justify spending another 400 on the gold valves right now. At any rate, I think just going through the suspension and replacing the oil and seals will probably make a noticeable difference compared to the worn out junk that I am currently running.

I think just going through the suspension and replacing the oil and seals will probably make a noticeable difference compared to the worn out junk that I am currently running.

Correct. Refreshing your clapped out suspension isn't going to do anything but good things for your ride.:bonk:

Just to confuse matters more I'm using a shock off a '07 YZ250F on my '03 YZ265-WR 2-stroke. Fits like it was made for it. Note that the valving does not feel right; looks like I'll be going into the '07 shock soon.

Well I've gone through the suspension and now it feels much better!

I ended up going with a race tech setup for the rear shock (I found a gold valve on ebay for $110 so I went for it). I also purchased Racetech's recommended springs and I must say now the bike feels a lot better. cornering is easier to boot.

For the front I just replaced the seals/bushings and fluids.

When I first got on the bike to set the sag the bike felt really stiff, like something was weird with the shock. Anyway I went ahead and set the sag and went riding yesterday. One thing for sure the shock freed up quite a bit after riding for a few mins. I will re-check the sag before I go out riding again.

I want to take my Factory Connection suspension off my 2004 YZ 250 F and put it on my 1998 YZ 400 F. Does anyone know if you need to swap the steering stem and bearings as well? 

Thanks for your help this is my first post.  

Edited by RLF

Both use the same bearings, but the stem on the 250F is 12mm shorter, so you'll want to switch that.  Note that the forks are also shorter by the same amount.  Compensate with a little extra sag. 

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