Going back to WR timing... YZ timing blows.
Posted December 11, 2001 - 07:35 AM
I thought the same thing a long time ago. I went to YZ timing and hated the lack of control I had. I had so much trouble in Moab when I first went to YZ timing. I was down quite a bit when I'd give it gas in a tight spot and it would take off on me.
Before I went back to WR timing, I tried the 52 tooth rear sprocket on the advice of a T-Talker. Made all the difference in the world in control. I was able to control the bike in all the ugly spots. Then as I got use to it, no more problems, except when my ego gets bigger than my abilities
Posted December 11, 2001 - 07:51 AM
please have a little more curtosey next time your time of the month comes around and you read someone else's opinion that doesn't agree to yours. they are entitled to it.
p.s. i am not trying to cause trouble with you on this one, and i hope you don't feel the need to reply with another "factual" report of my inability to give 100% of my time to riding, because this is what you call constructive criticism.
Posted December 11, 2001 - 10:35 PM
There was only one difference, the vortex had the yz rev limiter at 11.5k instead of 10.5k of the wr.
I didn't know that this issue was resolved.
My measurements show the yz cam timing to be typically 106 lca on both the intake and the exhaust.
After cutting the barrel base gasket surface I realized that what I had just done would modify the cam timing again so I went ahead and installed the falicon adjustable sprockets and after some deliberation came up with 105 in lca and 106 ex lca.
I also found that my 44o cc motor like a small main (155-165) coupled with the ekp in the middle.
All of my midrange gurgling has been resolved by moving to a smaller main.
I tried a bunch of different fuels and oxegynating compounds blended in with different jetting.
I would be happy to send all of my data to anyone who is interested, I just have to plug my friend Dale Lineweaver(Pace pro singles championship tuner).
Posted December 11, 2001 - 11:53 AM
I see Taffy’s passion for perfection, I also see myself (Gray hair does this to you) and some of you who are asking why MUCK around with something that works well for a small gain in performance. BUT it is fun to mess around with the bikes. I have 6 motorcycles (street and dirt) sitting in my garage and anytime my wife complains about them I tell her: you rather deal with 6 other blond, brunet and red hairs or the beautiful bikes that are sitting here and not asking for ^&*^&.
Seriously, the valuable information provide by all of you will help us to make not necessarily better, faster bikes; but, ----- inspire some of the new comers to the WR family to make decisions that they may like or not and then, learn from it.
OOPS, Gotta go back to another stupid teleconference.
Posted December 11, 2001 - 02:15 PM
Dan, I would really like you to ride my WR. I know you have invited me to ride on several occasions and I will take you up on it soon. I recently rejetted with Taff & JD's recommendations. I was under the impression that my bike could not run better, but after having a go at it I was blown away by the improvement. It took awhile to dial it in, but now I'm able to run taller gearing and it has way more pull though the gears than it did before the rejet with 14/50 gearing with gobs of top end. I'm also running a 10oz flywheel weight. It mellows the YZ timing "hit" and made it more trackable for me.
I'm defiantly sticking to the YZ timing. Me like.
ps: What ever happened to OTBA?
Posted December 11, 2001 - 02:41 PM
Laurie, Steve, and Debby are all good people.
There is also some talk of another guy doing some new grinds with CNC equipment.
I think there is more available with the right grinds but it will send us back to the drawing boards for a complimentary pipe design.
The CNC grinders allow us to isolate the base circle from the duration, for one. Actualy being able to modify the duration and lift while maintaining the same base circle offers the grinder a lot of latitude in one off designs.
First I want to do a 2mm stroker crank, then I will dig back into the cams...
Posted December 12, 2001 - 02:18 AM
glad you didn't all walk away from this. it's so easy to come back with "i'm busy" and one of you did but as i pointed out and will repeat, with 5,0000 blinkin members out there we must have one person prepared to go.
SFO the main jet can be used as a guide to your porting and valve sizes (ie gas flow)but i'm sure you know this.
i've heard someone say before that there is a difference in ignition and i maintain that i don't think there is.
SFO, nothing wrong with a vortex ignition. it's just that someone else ran them on the dyno (WR v YZ ignition) and said there's no difference.
BTW. people say that there is a difference because they use different part Nos. but i THINK that every year every model gets it's own part No.
see boys, the jury is out. so stand firm men, shoulder to shoulder and ? the ignition curve difference.
SFO, great #'s (Nos) on the cams. one thing i do know is that SFO's bike will produce more peak power than mine. the neare the numbers are to 110d the better. it would now nice to try 110d and even 112d.
which cam needs to move? inlet or exhaust?
my indexed wheels have had 1d marks put on them by my engineer simon. all i would need to do is;
tank, seat off, jet wash and blow dry and perm. rocker cover off and then undo two 10mm bolts to adjust the cam. probably each mod would need to take 20-30 minutes. if you stick to the road you could do lots of little changes and when you get a feel for what is working you then take it for a proper dirt ride. knowing what you tried you can then go in the right direction.
i also think that my 14/48 and 15/48 is higher than most of you and so any real lack of torque i see is quickly exposed.
you must always get your jetting right before you do anything else. the WR and the YZ timing will barely change your jetting.
it's your exhaust, air filter, airbox lid that make the most difference. a yz timed bike shoul;d run leaner by (i'm guessing 2-8 on the MJ) like i said; not a lot.
once you initial cam timing is done by a shop (they won't show you) or a mate(he will) you can move the wheels yourself.
a good shop will see what's wrong with a grind straight away if they've done it long enough. it's often history with the manufacturer using the same grind and having the same failings on all their models. the answers therefore t themselves.
ron, stroker have played that game for over a year. that really is out of order (1 1/2 years possibly).
as for those that don't feel they can offer too much i say this;
do you agree that the YZ tank top profile is the best?
do you want to still hold three gals?
why didn't you back the call or help start it now for that very tank?
would you still be happy with 2 1/2 gallons if it could be done?
Posted December 12, 2001 - 06:14 AM
BTW - it is not my experience that Yamaha issues different part numbers for different model years. If the part is common to different years, models, or even product lines, the number remains the same. To do otherwise would be a logistical nightmare for Yamaha and thier dealers.
If you don't believe me, the next time you need an oil filter, order one for a 1987 Yamaha Big Bear 4x4 ATV, or if you have to replace your ign. coil, just order one for a '99 YZ 250. All the same part numbers. P.Z.
Posted December 12, 2001 - 06:43 AM
P.S. One thing that just dawned on me. The US WR was YZ timed so that throws everything out the window.
[ December 12, 2001: Message edited by: Mike in Silicon valley ]
Posted December 12, 2001 - 08:00 PM
Cam timing, is it going to make that much of a difference to overcome rider ability. I think not...I like most of the yanks haven,t had the pleasure to ride with you, but I am certain you use every horsepower available that can be produced and need more. I Know I do.... thats why these guys are buying these larger displacement bikes because they are using all the WR has to offer and its just not enough. If I only had the money for one of these larger more powerful bikes then maybe I could keep up.
Thats my story and I am stick'in to it, HUGE
Posted December 13, 2001 - 12:14 AM
howard, i'm not using all the power because i ride tight woods and there's no raw power there.
if i lived in cali i would ride your baja deserts and plead for more BHP.
i need grunt. i'm only a clubman and anybody who knows me knows i've only ridden dirt since feb 2000. i need to touch the throttle and shoot forward without changing gear.
i need to pop the front wheel like you can with a two-stroke.
if you ride only 50 yds between corners you need bottom end power. this bike is essentially a MX bike.
it's been changed to an enduro machine at no extra cost. the extra machines sold make it into a profitable machine.
yamaha are going to have to become enduro specific when they bring out the 2003 machine.