XR400 Springs Are On - Details and Reactions

moridin

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#1
Ok- just some comments since this seems to be a popular topic of conversation.

I ordered the XR400 springs from Ron Ayers – http://www.ronayers.com

Here are the part numbers:

51401-KCY-761 SPRING, FR. FORK $38.41 X QTY 2 = $76.82

I am ultra cheap – so this is the best deal out there :thumb: .

After a few visits to my local dealer – the 96-98 springs for the XR are .39, the 99-04 are .40. The part number I listed are the .40.

Installation was pretty easy – total from start to finish was about 3 hours (and I am slow at anything). If I had to do it again, it would be half that.

I won’t go into any of the details since that has been discussed ad nauseum. A few things I did notice was that even though I fabricated a spring retention tool – I found that a pair of vice grips (needle nose style) worked really well.

I tossed the stock spacers and went searching for PVC. Luckily the house they are building next to mine had a huge pile of plumbing scrap – what do you know, PVC schedule 40. After measuring the complete stock setup – I wound up with a new spacer that is 1 3/8” or 35mm. This yielded about 10mm of pre-compression.

The stock oil that was in my new bike was disgusting. I am not sure what was in there – but it had the consistency of baby snot (I am not exaggerating). I was certainly glad to get that stuff out of there. May have something to do that my bike at new on the showroom for 3 years. Anyway – filled to 100mm from the top with BelRay 7w. I was going to go with Mobil One ATF – but after reading some more threads – the Bel Ray just seemed to be more appropriate. 1 quart was enough.

Bolted it back up…Reactions?

WOW! :yeehaw: Don’t spend another $100 on your KDX until you do this easy mod (unless of course you spent the big bucks for real suspension). This has literally transformed the bike. We have snow and ice on the ground – so my test run as short lived – but the difference is really noticeable. You will notice the difference the moment you mount the bike – that initial 2 inches of ride sag is gone. The bike just feels balanced.

I noticed that when throttling off – the bike doesn’t dive forward like it used to. The ultra plush ride that I was accustomed to is gone, however. Don’t get me wrong – it isn’t like riding an MX bike – but you can defiantly feel a bit more of the trail. I intentionally rode it pretty hard over some roots and some 2x4s (simulated roots) – and I could not be happier – soft, yet reactive.

All in all – SUPER UPGRADE.
 
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#3
Not to argue, but consider a lesser preload and a bit lower oil level. You will feel less of the small stuff.

Experiment some to find what works the best for you.

A drop of 5mm of preload and 10ml of oil level in my forks had a huge impact on handling. By 'huge', I mean going from 'I'm about ready to dump this whole front end.' to, 'Hey! This works great!'

imo and all that.

I don't recall you mentioning whether or not you have set your shock spring sag. Gotta do that! The two ends work together.

Hope this post isn't too many lines long!! Can't have that!! :think:
 
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#5
I'm interested in doing this, but don't want the bike any taller. Does it make it taller?
 

moridin

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#6
No taller that I can tell.

I think the stockers were way too soft. My forks would drop 2+ inches with me sitting on them - and it kind of felt nose low.

It feels much more balanced now. I did set the rear up again - and it is a big improvement.

Mine is a 2001. I weight 165 bare - and 182ish with gear.
 
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#7
I love the xr 400 springs in my bike. My brother has a stock 220 that I cannot hardly stand to ride because of the mooshy suspention. To any one thinking about getting the xr springs do it, you will be happy.
 
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#8
As I posted to another thread on this same subject. Spend $100 (or a little less) on the fork springs installation and enjoy your KDX or if you ride it over 20 mph you will spend it on parts and medical bills and not enjoy it!
 
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#9
fwiw...

I didn't measure before/after, so I couldn't say the bike was or wasn't taller.

I didn't notice any difference.....whatever that's worth.

Most of the time seat height doesn't matter while most of the time suspension does matter.

I'd choose better (even real good?) suspension over a bit of seat height change.
 
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#10
I had a set of XR springs left over that I installed in a friends 86 200 front end that was retrofitted to his 83 (disc brake addition also there. Poor college student at the moment). But he was reluctant to go stiffer springs cause he liked the plush ride.

I finally got him to install the springs after he realized he was bottoming the fork anytime he touched the front brake on the bike. After the install, he was amazed the front end was not harsh at all and worked better than before.

Imagine that!
 
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#13
If its the Mobil 1 ATF

I think :think: its like 7.5 wt


I bet a search would clarify it




:eek:
 
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#14
A search came up with:

ATF weight appears to be around 0W20 equivalent to automotive oil scale, although you probably have no concern for the "W" value, as it is determined at -20 - -40F. When compared to typical "fork oil" viscosities, it appears to be around 10 (at least Mobil 1 ATF).

(http://faq.f650.com/FAQs/ForkOilChangeFAQ.htm)
**************
And....
I've been told it's about 7 weight. Although I was told this by an excellent motorcycle mechanic, I can't state with absolute certainty that it's correct.


And...
I've been told by a long time parts guy that it was about 5 wt. It's pretty light.

And...(kind of addresses the whole numbers game)
As with
motor oil, the Society of Automotive Engineers (SAE) developed a
viscosity grading system for gear lubricants. The SAE system lists
requirements for both single and multi-grade lubricants, but does not
differentiate between EP and non-EP fluids. Typical SAE gear lubricant
grades include SAE 80, 90, 140, 75W, 80W, 75W-90 and 85W-140. Although
the grade numbers are larger than those associated with motor oils, gear
lubricants are not necessarily heavier. The two separate grading systems
are used to minimize confusion between motor oil and gear lubes.


I've never taken a properly cooled jug of mobil-1 atf, poured it thru a viscosity seive whilst looking at my timepiece.

...but only because I don't HAVE a timepiece. Otherwise, I'd be on that like white-on-rice!

;)
 
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#15
I've never taken a properly cooled jug of mobil-1 atf, poured it thru a viscosity seive whilst looking at my timepiece.

...but only because I don't HAVE a timepiece. Otherwise, I'd be on that like white-on-rice!
:eek:

BTW, I read it somewhere in Suspension Q&A with MX-Tech's Jeremy Wilkey


I guess on Mobil 1's site they claim it is a 7.5, but then again... I read that too! :)