Ti valves and 01 springs



7 replies to this topic
  • smitty33

Posted December 23, 2000 - 07:07 AM

#1

Has anyone else thought of runnin' the 2001 valves and springs in their 2000 426?

If it makes for quicker throttle response it would be all good right?

Any Thoughts?

Merry MX-Mas
Smitty

  • Taffy

Posted December 24, 2000 - 01:22 AM

#2

in my opinion it would be a waste of money. only if there was an over rev facility would it be possibly worth it.

but there isn't, so forget it.

if stroker EVER get these cams made, which they haven't so far, that would be worth it.

IF & it's a big if the cams were developed with the ti valves & springs in mind.

i would then expect it to become vital that an exhaust was designed to match such a dramatic change. each hop up makes it more important to run the carbon airboxes as well.

Taffy

  • Boomer

Posted December 24, 2000 - 03:13 AM

#3

Keep in mind, that ti is softer than hardened steel. These bikes are built for racing and the ti suits the design intent and user purpose. So, for someone wanting the slight gain in performance, "ti-ed" (pun intent) to the higher maintenence, then it may be worth it. Otherwise it is not going to make that much difference. I would venture that most of us do not want to experience faster valve wear which means higher maintenence.

Some of us bought our bikes with hopes that we would enjoy long durability and that is what I am counting on.... let us know how your conversion works out if you decide to go that route...

rubber down'n rippin grooves...

Boomer

  • smitty33

Posted December 24, 2000 - 07:39 AM

#4

Good point about the faster wear, I think i'll wait till I see some reports on the duribility of the ti valves and springs.

Taffy:
I was under the assumtion that the lighter valves would make the bike rev quicker, due to the decrease in weight of the valve itself, and this might also help the hesitation off the bottom that alot of 00 owners cant seem to shake.

As far as the cam, I thought the ti valves were the exact same shape and length, so how does the cam affect them? I was a two stroke guy till last year so i'm still learnin'.

thx
Merry MX-Mas
Smitty


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  • holeshot

Posted December 24, 2000 - 08:18 AM

#5

The advantages of lighter valves won't come into play until higher RPM's are reached, so I doubt if it would eliminate hesitation off the bottom. For reasons unknown, my '00 426 doesn't have the hesitation problem.

I've read somewhere that the Ti valves require a different valve guide material, so if the guides aren't replacable, an entire cylinder head may be required.

  • Boit

Posted December 24, 2000 - 05:50 PM

#6

This IS an interesting idea. I was wondering about this a while back also. Not being a metalurgist, I was wondering about the durability of titanium as a valve material. Is there only one grade of titanium? Can it be tempered to hardness comparable or even better than stainless steel? I have titanium footpegs and wanted to sharpen the spikes and found that these pegs were extremely hard. I completely wore out 3 Dremel bits sharpening them.

  • Scott_F

Posted December 24, 2000 - 08:53 PM

#7

IMO, ti is not as hard or wear resistant as some steel alloys. I once had a ti countershaft sprocket. It seemed to wear faster than a steel one would. I have had ti footpegs that wore reasonably well, but the teeth did wear down. OTOH, I have found that ti bolts are tough to cut.

As for the ti valves, I would be more worried about the seats than the stems. It would be interesting to hear of the experience of race car engines with ti valves.

  • holeshot

Posted December 25, 2000 - 12:27 PM

#8

This was printed in the Jan. '01 issue of Dirt Rider, pg 126.

"According to Yamaha, the valve guides in the head of the '01 YZ426F differ from that of the '01 head. Because of this, it is not possible to just switch your standard valves to the '01 titanium valves. You would have to buy an entire head assembly from an '01."

Of course, people who read and post on ThumperTalk are far too intelligent to believe anything from a magazine, so I'm just posting this as a reference. :)

[This message has been edited by holeshot (edited 12-25-2000).]





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