More power in the UK (Taffy?)

I would like to increase the power a bit on my stock 2000 WR400. At 110kg in my socks (God only knows how much when kitted up), I am starting to trail behind others on some lesser bikes!! I want some more low and mid range range power, but am overwhelmed by the volume of suggestions on jetting.

For a first attempt, should I jet or should I go for a power exhaust (bearing in mind that trail riding and Enduro sound restictions in the UK).

Can anyone give me a shopping list of jets and needles to try? and does anyone in the UK have any second hand parts (exhaust included?).

Thanks all.

A pipe and jetting would be a great place to start. And since your on that side of the pond, look for Arrow exhaust. Rumor has it that Arrow has the quietest exhaust known to man. Search for the topic "jetting q's" and read the whole thread.

A better place to start would be suspension work. If your smoother...... your faster and you'll have more endurance. Just a thought :)



I'm jetting my 2000 WR for a YZ exhaust.

See my post on 2000 WR jetting.

Keep me advised of YR progress.

Search way back for search terms "Adjustable cam gear", use the "and" search option.. read Taffy's stuff on these, he seemed to get a lot more torque out of the thing by precisely indexing the cams... As well as that, jetting is good, and a pipe will give you a bolt on hit...

Riding fast is about rider skill and confidence, you can be faster than the others with good suspension, so make sure you have the right springs, settings etc, and you will pickup seconds here and there... you are using your suspension all the time, but your motor may just accelerate you for a short while... say 30 seconds, then you only have your suspension to keep the speed up...

If you have problems with the terrain, consider a steering dampener... will make you smoother and faster, with more confidence to hold your speed...

Good luck,


Thanks for the advice guys. I have had my front and rear suspension tuned for my weight by a company called Pro Racing in the UK - (heavier duty front and rear springs). Since getting it done, I have noticed a great improvement in handling. My last outing before the upgrade, was a trip to Wales (very rocky and bumpy and wet in places), and traction was a problem, but not any more.

I will check out the threads.



do you live almost in the farm at whaddon!

the jetting is established although some will for obvious reasons have found other settings i know that mine (shown at the bottom of this message) will be spot on for you.

the heavier you are; the more torque you need and yes indexing the cams is the way i went. but remember that my jetting is EXACTLY for the euro pipe and you shouldn't have any hesitation therefore in following it to the letter.

as for more torque, more cc's is the obvious one and in my case i re-timed the cams. more cc's ain't always easy.

nothing else has that effect. i think you ought to do the jetting and then come back to us.



Yep, Whaddon is about 10 minutes from me. I haven't done their track yet (just the main area), but am joining the TBEC to start racing in the Enduros, so no doubt will soon.

I will give the jetting a go. Where is the best place to buy the bits, Yam dealer, or specialised shop?


go to the importers

allens R & D. 01949 836733 /4 to fax them.

TBEC member #102 :)


go to the importers

allens R & D. 01949 836733 /4 to fax them.

TBEC member #102 :)


Tried Allens again, and still no luck. He said he had a 60SJ from a YZ, but also said the thread was different.

Taffy, what is the difference between your timing and YZ timing. I checked mine at the weekend, only to find that I already have YZ timing.


essentially you had the front cam turned back a tooth. with my timing it goes forward 1/3 of a tooth so that it's then 2/3 back from WR and 1/3 forward for YZ.

the inlet wa only changed 1/6 of a tooth. it added a little more torque for no loss.

when old man alan was around he would have sorted you out. i can't believe that there is any difference in the thread. what there IS a difference in is whether you have the mk1 or mk2 carb on it!

now that difference i can understand.


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