The YZ400 is not that great a bike!

Rich Rohrich

Moderator / BioHazard
LIFETIME SPONSOR
Jul 27, 1999
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I pretty disappointed that Pete didn't bother to ever respond to anyone in this thread. He signs on to the board, posts an incredibly ill-conceived rant and then disappears. I was hoping we'd get some actual dialog on this subject.  OH WELL
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Rich Rohrich
Applied Fluid Dynamics
rich@dirtrider.net
www.eric-gorr.com
 

A-Loop

Member
Dec 7, 1999
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Oops, sorry Rich. I've just been enjoying reading everyone's response to my post about the YZF. I guess I should have been more.....responsive. Anyway, I'm NOT pissed at Yamaha, quite the contrary. I'm really impressed at all the changes that they've made to the 426 this year. It's just that I'm of the opinion that we've got a long way to go before the 4-stroke reaches it's true potential. That's good news, right?

If you want discourse, wait to you hear my Cannondale Rumors! As soon as I can think of a tactful way to type 'em, i'll post 'em.

Seeya on the Trail!
 

TexKDX

~SPONSOR~
Aug 8, 1999
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With only 60 miles on my WR (tuned to YZ specs - see  "WR Myths and Truths" post) I have a decent handle on the supposed stalling "problem".  It is pretty simple, just pull the clutch in and keep the throttle cracked in slow speed situations.  But wait a minute, that is how I ride my 300EXC!?/&!

OK, high compression, short stroke, minimal flywheel weight equals a motor that does not chug like a long stroke, low compression, heavy flywheel motor.  Glad I figured THAT ONE out.  Hey, the bike still chugs pretty darned well off the cam.  The power it tractible and the bike accelerates pretty well in this range.  Yes, you have to clutch it a little more than an XR in really tight stuff.

But wait now, what happens when you give it the gas and fan the clutch?  The motor wraps up like a 250 2 stroker with a light flywheel, and you do your best to keep the front end on the ground!  The bike rockets forward and pulls like no other 4 stroker when on the cam.

All this in a YZ250 chassis, with say a few too may Big Macs in the old saddlebag of extra weight.

Hey, this is one fantastic motor and motorcycle.  A step forward? you bet.  One irony in all this is the reliability.  Personally I did not expect this motor when it came out to be durable.  But think about it - the Genesis 5 valve motor technology has been around since when, 1986?  Yamaha had done 95% of the groundwork before the 400 was ever conceived, so execution was a relative snap.
 

bud

Member
Jun 29, 1999
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Pete, how bout posting these cannondale rumors on the flame board? No tact required there
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MX Tuner

Member
Jun 2, 1999
34
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Some good dialogue going on in this thread. But Pete, I'm a bit disappointed in your comments. It almost seems as though you're simply trying to start some sh!t. Certainly someone of your intelligence and familiar with the industry and bikes in general, knows the finer points of the poor argumants you bring up concerning the YZ/WR 400. No, it isn't the "perfect" 4 stroke but it's the best thing out there for the time being. It is very cost effective for a stock bike. Sure you can get lighter, but who wants to deal with a Husabergs quirks, reliability, resale value, parts availability, etc.

You complain about the complexity and then want the rotary valves F1 is experimenting with. You want basic but then want a CF con rod? I think you need to find a new crack dealer because you're getting some bad drugs. Sorry if I come off sounding like this is a personal attack (believe it or not, it isn't), but I'm scratching my head wondering because I know you are very familiar with both sides of the argument.


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MX Tuner
mxtuner@mindspring.com
 

A-Loop

Member
Dec 7, 1999
3
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Yes, I agree there is some great dialog here. I don't know what you mean about trying to start something, unless it was to start people thinking.

Let me restate my point. Here goes... If you ever rode an old Triumph single, if you ever rode an old Husky 510 single, if you ever rode an International Harvester Tractor, then that's the TYPE of powerband that I'm speaking of. To me, an ideal fourstroke powerband is totally flat, meaning that it makes nearly as much power at 1000 rpm as it does at 7000.
As revolutionary a bike as the YZ400 is, nobody can deny that it is a very peaky powerband, and in this area I contend that it resembles a two stroke rather than a four stroke.

As to complexity and weight, two negatives of any dirt bike, my point is that they go hand in hand sometimes, and that I welcome changes which reduce both.

Everybody is entitled to their opinions. I know that there is some smart guy right now reaching for his keyboard to tell me I should go back to the three machines listed above if I don't like the YZ, so let me state that I have owned the Triumph, the Husky and the International Harvester, and the International had the other two beat on handling and power, and lost only slightly in the suspension department. I LIKE YZ400's, I just want a fourstroke to purr like a fourstroke. 'Nuff said.
<p align=right>01-21-2000 :Edited
 

BigBore

Member
Jun 16, 1999
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I'm with A-Loop on this one.&nbsp;&nbsp;The "rev to the moon" style of power just doesn't interest me.&nbsp;&nbsp;Again, this was a big factor in buying my 600...I don't have to rev the beans out of it, so in turn its gonna last a long, long time.&nbsp;&nbsp;

My friend has a YZ400, and I've ridden it quite a bit (in very tight singletrack, to mx-style grass track), to see what I'm "missing out on."&nbsp;&nbsp;Yes, it is a nice machine, but not for everybody.&nbsp;&nbsp;It felt like it wanted to stall too much in tight going (even with a 12oz flywheel weight)...I know thats just my riding style showing, though.&nbsp;&nbsp;Everytime I ride it, my friend tells me, "you need to rev it more, you're not revving it enough."&nbsp;&nbsp;And to my ears, its screaming, but I'm used to an engine that makes its peak power at aroud 6,000 RPM.&nbsp;&nbsp;About the only thing I liked about the YZ was the inverted fork (very quick and precise steering), and the thin, flat feel of the bike.&nbsp;&nbsp;

Again, I'm not saying its a bad bike, its a great bike.....just not great for everybody.&nbsp;&nbsp;
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BigBore
'99 XR600R

Yes, it's fast...no, you can't ride it!
 

michigan

Member
Mar 9, 2001
424
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I must admit that I've never ridden a 400/426, but I DO know that I just bought a bike that is 30 pounds lighter, makes more low rpm torque, more high rpm power, and always starts on the first kick (even if it has just bounced ass over teakettle down a hill), and it doesn't hurt my ears.
Oh, and it was a grand cheaper than the yamaha four stoke.

Maybe it would be different if kawasaki sprinkled a little "technology" on it!
 

SFO

LIFETIME SPONSOR
Feb 16, 2001
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super stale thread but in rereading it I am wondering something.
The triumph cub and the husky510 are nearly extinct.
I am curious % wise how many yzfs will be left when they are 20 years old, compared to a cub or a husky.
I personally like the light flywheel feel.
Who in there sober mind would call a aircooled husky 4st reliable?
I got a husaberg you might be interested in, early 90's vintage...
 

Ol'89r

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Jan 27, 2000
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Shaltac Wasn't there a time when the 2 strokes were experimental tempermental beasts that were heavy and didn't perform said:
Dayum. Who dug this one up, Bill?? :rotfl:

Gonna have to fire up the way-back-machine for this one. :laugh:

Shaltac.

When the 2 strokes first came out they were not very impressive. Materials for pistons, bearings, seals, rods, etc, etc, were substandard compared to what we have today. The chances of finishing a race on one without seizing a piston or fouling a plug was slim to none. You had to ride with one finger on the clutch lever so it didn't pitch you off when it seized. They were very hard to ride since they didn't have power valves to control the torque so, they were either 'off the pipe' or 'on the pipe'. Nothing in between. It was like toggle switch horsepower, not a smooth powerband. The ignition systems were not very good and didn't produce a hot enough spark to keep the plugs from fouling. That along with the lack of good 2 stroke oils. Most everyone used Blendzol, a bean oil that smelled like you were running fuel and made your eyes burn. With the expansion chambers they were very loud and during a race you would pass many of them while their riders were kicking, kicking, trying to start them. Sound familliar???

About the only thing they had going for them was they were lighter. Of course you made up for that by having to carry a pocket full of spark plugs and a plug wrench. Most everyone thought they were only a fad. Probably won't be around for long. ;)

Well, thanks to technology and the advancement of materials, the two stroke has come into its own. High silicon pistons, special coatings for cylinders, power valves, electronic ignition systems, chrome moly, magnesium, titanium, blah, blah, :blah: They are now, state-of-the-art race bikes.

Four strokes are undergoing the same transition. By using lighter materials, better materials and modern electronics, the 4 strokes are now very close to the 2 strokes as far as the way they handle and the weight. Much of this technology has been around for many years. The difference is in the materials now available to us. The rotary cam valve has been around since the early 70's. There was a bike called a Zimmerman that used two hollow shafts that rotated and had the carburetors attached to the end of the shafts. This bike put out tremendous horsepower and reved to the moon. It was very successful in So California desert racing. The main drawback was the frame kept breaking and the bottom end could not hold up to the high rpms that the engine was capable of.

Most of the technology that we think of as new, has been around for many, many years. Monoshocks go back to the 20's. The difference today is the materials that are available.

It's funny how much advancement in technology we have seen just since this thread was first posted. I purchased a WR400 and thought it was the best motorcycle I had ever owned. Trail rode it and raced it and did pretty well on it. At least until the CRF 450's came out. The CRF's were so much faster and better than my WR, I couldn't believe it. Having won races on the WR, I couldn't even keep the CRF's in sight the following year.

Back in the day we took 450 lb street bikes and stripped them down, machined everything and ground every extra bit of metal away and made 370 lb racers out of them. Today you can walk into your local dealer and walk out with a bike that is very competitive. A lot of people complain about having to check their valves and maintain their bikes but, back then we literally had to build our racers from scratch.

I know what Pete is talking about in regard to the old thumpers torque. Having ridden and raced Triumphs for many years and owned and trail ridden XR's, I like the torque that the old long rod thumpers had. And yes, I even raced a Tigger cub on shorttrack. Still own several Triumph twins. And although that type of torque works very good on trail, it doesn't cut it on a track. Especially a mx track. For that reason I keep my XR for trail and have a CRF450 for racing.

But that was then and this is now. What we are seeing today is the resurrection of the four stroke. This is just the beginning, the best is yet to come. Everyone complains about the cost's of the new bikes, the electronics, the complexity. But that is what it takes to stay up with technology. We have some fantastic machines available to us today. Most all are very good. Two stroke, four stroke, red one's, blue one's, yellow one's, green one's, orange one's. Pick a color and go ride.

Oh, and btw Bill. I know where there are a couple of tigger cubs and they still run. :yikes:

Ol'89r
 
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