Updates - Advice required

G'day all. I want to run some ideas by all of you and would appreciate any feedback.

1. Big Bore Kits

The latest info. The 420 kit works for the 98WR/YZ and the 426 IMS kit works well with the 99WR/YZ

2. Footpegs

Any takers on good quality footpegs? The Ti units are very expensive. Are they really worth it?

3. Sprockets

Which is the best. Steel, Aluminium? Renthal, Sidewinder? Help is required based on experience, not what the mags say.

4. Chains

What type - DID?

5. Fork upgrades

I read that the best upgrade is by going to a 0.46Kg/mm fork spring or a 0.47Kg/mm. Any advice?

6. Airbox

A little research here. the airbox apparently improves Hp and certainly improves throttle response dramatically. Is it worth AU$1,000? Depends on whether or not you really need it? I think I may need it.....

Anyway, there are my thoughts. Any feedback would be appreciated.



Because of my cylinder damage, I was going to have it re-coated. Re-coating is only financially beneficial if you have had the cylinder ported (read-2 stroke). I will end up replacing the cylinder/piston/rings. If the big bore kit does not wreck my lower end (transmission problemns??), this would be the way to go.

Personally I think the aluminum rear sprocket is just a bunch of fluff. Sidewinder now makes the stainless steel sprocket. It is pricey, but I think much better than aluminum. If someone else paid for my sprockets I'd go aluminum, I pay for it so steel is the way I'd go.

Titanium is great for Russian Alpha class attack submarines (not really - during deep dives the Ti compresses and becomes very brittle. Russia stopped using it, I believe). Footpegs...Give me a break!!

You may be on to something on the heavier fork springs. Rumor has it Yamaha stuck in lighter springs and kept the valve stack the same. Personally I think the stock forks leave a lot to be desired.

Chains...Hell, I don't know. I have used Tsubaki, DID, Sidewinder. I think the Sidewinder gave me the best life. But, the sprocket will have a direct impact on the chain, so...A better sprocket should do what...???

Airbox: For the man that has everything. I punt on the airbox.

Of course, this is all my own opinion. I am entitled to that.


99 WR, all YZ mods, de-octopused, OEM YZ tank and seat, jetting by Clark.

You may be on to something on the heavier fork springs. Rumor has it Yamaha stuck in lighter springs and kept the valve stack the same. Personally I think the stock forks leave a lot to be desired.

I think the yz400 and wr400 both have .46 fork springs but the valving is different, one has a one stack and the other has a two stack whatever that's all about... anyways I have .47 springs with yz damping 'cause I'm heavy and I'm riding MX a lot now. The rear spring is the thing that is way softer on the wr (I think a .52 vs the yz's .56) once you get the back end up so it doesn't sag so much the steering is much quicker.

BTW, Terrycable has a new product for our bikes called a "front axle extender" for quick wheel removal. I don't know what it is, does anyone know?


'99 WR400

'92 GSXR 7/11

Visit my photo album AT YOUR OWN RISK!! My photo album

Anyone here a sportbike fan also? Then visit us here at www.insanespeed.com

Hey Mitch, I have a friend that uses a Sidewinder sprocket and chain and is very happy with the life. I think that the use of the sidwinder chain with the SS sprocket is the key to the life. I think we tried to figure it out and it came to 3 times the life of Aluminum sprockets and new chains each time I changed mine.

Thanks for all the feedback guys.. Let me sum up.

Chain and Sprocket



Russian Sub


Cheaper thrills as a "whore house" :)


Pay the damn money and get them taken care of


I"m sold on the DID "X" ring chain and it is the only one that goes on my rides.


Where did you hear that the 426 on the 99's was working out ok without causing other problems??


As far as the chain goes (I'm still running the stock sprockets)

DID - 520VM (the new X-Ring version "gold" colour), it has yet to stretch and seems to be wearing well.

Paul Card

00' 426

Hey Clarke,

The 426 IMS upgrade for the 99WR's info came from two seperate sources.

1. Dirt Bike magazine

2. Private Source in the industry

If you would likie to discuss offline, I can possibly give further details some tiome next week. This week has been completely flooded and I have not had the time to get full details from my friends.

Mitch - supermotard_99@yahoo.com

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