WR vs YZ timing

[Steve wr400]

I just bought a 2000 WR400F a month ago. It's got the stock pipe on it and not sure if a new one will do much good. Especially with the noise issues floating around now days. What I'd like to know is what exactly happens to the bike when the timing is advanced to that of a YZ? I've asked 3 different shops and got 3 different answers.

If it helps, I ride trails most of the time. Race desert, Hare-Scrambles, Hare & Hound, and GP's a few times a year.

Thanks

 

[parish8]

this wont help much, on a wr250f changing to yz timing increases the low to mid power section of the rpm range, it doesn't have as much impact as the grey wire mod or a new pipe. it also doesn't create any kind of mid power hit it just smoths out the power, makes it more linear. I have no idea if it is the same for a 400f.

 

[Boozer]

Originally posted by parish8
this wont help much, on a wr250f changing to yz timing increases the low to mid power section of the rpm range, it doesn't have as much impact as the grey wire mod or a new pipe. it also doesn't create any kind of mid power hit it just smoths out the power, makes it more linear. I have no idea if it is the same for a 400f.

first up, look at thumpertalk when it starts running again, since this very topic has been discussed. do a search WRvsYZ timing and you will find many threads.

Parish8, i think you may have it backwards. for me, the switch to YZ timing gave me a dead (in comparison) bottom end, average mid, and a ripper top end. there is indeed a 'hit', and when you WFO the gas from low speed in a high gear, you will hear the engine gradually increasing revs until the sudden 'hit' appears. much like a two stroke, no doubt about it.
for the WR400, i think it may be too much for trails. since it's big in the bore, riding it pretty much anywhere in the rev range is okay. losing a bit down low for a hit up the top probaly isn't worth it.
but what would i know about the 400's. guess you should try it and see.
you could always change it if you don't like it, but it's kinda a big job on the 400.
oh, and for me, i thought the YZ timing made the best power gains compared to any other mod, pipe included.

 

[jmics19067]

when I had my 98 wr400 changing the cam spec too yz plus cutting the throttle stop and uncorking the exhaust plug it was like riding a kdx 200 compared to a 250 motocross bike. It felt like it had more power every where. And for some strange reason the suspension all of the sudden felt harsh:scream:
Any way I bought an fmf power core and got a little more power yet got really loud and saved a heck of a lot of weight! which in my opinion was worth it just putting the darn thing on a bike stand. Would of loved to try one of them new fmf power core q's but they werent around at the time. The stock muffler is great to be quiet when corked and great to keep the USS Independence at a dock. No word of lie over 5 pounds differnce relatively cheap. Woulda loved to try the quiet fmf!!!!!!!!! The cam timing thing hey if you know how to read your manual rightand understand it, and know which end of a screwdriver is the business end go for it. If you have the confidence to retard the the exhaust cam one notch you can always put it back for free if you dont like it!

I have a lot of 98 parts crowding my garage left over if you are interested
Wiseco piston, subframe , stock exhaust, odometer&cable, plastic , tank and seat. either new new take off or excellent to good shape. let me know if your interested

 

[parish8]

i am missing thumper talk but this place is a good fix for now

boozer, i don't have alot of first hand experience since my bike came with all the mods done but i have spent many hours on thumper talk looking into the free mods for the 250f. the concences that i got was that all of the free mods plus exhaust even done one at a time only add power, some add it high some low but none take away power. also on the 250f everyone reports that all the mods are good weather you are on the track or in the trees, no loss of ridability or tractibility.

i can tell you that the exhaust that came on my bike(pc-t4) is way way too loud, i am about ready to trade someone for a stock set up even though the previous owner spent $400 on the exhaust.

 

[JWW]

Originally posted by jmics19067
I have a lot of 98 parts crowding my garage left over if you are interestedWiseco piston, subframe , stock exhaust, odometer&cable, plastic , tank and seat. either new new take off or excellent to good shape. let me know if your interested

Would the odometer fit a 01 WR250F? If so I might be interested

 

[wayneo426]

I have ridden two WR250F's, one YZ timed, the other stock. Both had the free mods done, and the grey wires cut. I preferred the YZ timed bike over the stock, mainly because thw engine really woke up. Without YZ timing, the bike seems very mild to me. Then again compared to the 426.....
jmics19067- The WR timing is retarded one tooth. Not the YZ. The engine is the same except for gears and the timing. The carb is another story! :eek:

Back to Steves original question:
IMO, if your able to really open up that badboy in the desert, change the timing. If your riding more trails, you might prefer the smoother WR power. In any case, both rip!!!!

Good luck.

 

[Boozer]

Originally posted by wayneo426
The WR timing is retarded one tooth. Not the YZ. The engine is the same except for gears and the timing. The carb is another story! :eek:

wayneo, looks like i stuffed my bike up! i retarded the exhaust cam one tooth also, to achive YZ timing. are you sure about your facts?

there isn't much between the carbys either. they are exactly the same, with the exception of a air cut valve on the WR. the YZ carb even has a casting on the side, where the valve is supposed to go. this is easy to disconnect, and is worth doing when going to YZ timing.

 

[jmics19067]

Would the odometer fit a 01 WR250F? If so I might be interested

not sure tried looking up the part numbers onthe yamaha of troy web site but they dont have a microfiche for a 2001 wr250f my part number should be 2- hr- 83505 -go -oo I woudl think the cable would have to fit but not so sure of the mounting to the triple clamp

 

[jmics19067]

jmics19067- The WR timing is retarded one tooth. Not the YZ. The engine is the same except for gears and the timing.

I could be wrong it has been a bit I do remember this though in the 98 when I had the valve cover off and the piston at tdc the timing marks where off on the camshaft and all I did was line up the exhaust cam to get the yz timing and the fussing with the cam chain tensioner . had a heck of a time trying to get my fingers to work holding the little screwdriver in the tensioner to keep it from poppingout and then trying to balance a gasket on a bolt while holding this whole flurshnugginer thing together and then trying to start a bolt. I do remember that was the hardest part of the job for me

 

[wayneo426]

I have heard different stories from guys that did the timing, and I always hear its a piece of cake. Not for me, anyway.

Boozer- I hope you didnt stuff up your engine too bad. From what Ive read on this topic, the WR is retarded one tooth. Thats what smoothes out its engine compared to the YZ. Then again, my name aint Brian Kinney. Cheers!

 

[Boozer]

http://www.off-road.com/dirtbike/jun99/hobbs/

scroll down to 'WR to YZ timing', and you will see that the author rotated the exhaust cam one tooth clockwise. to me, this will retard the exhaust cam by one tooth.