GYTR chains


54 replies to this topic
  • RCannon

Posted October 03, 2009 - 06:19 PM

#21

Who invented the O-ring chain? It claims on their O-ring that the chain is made by the inventor of the O-ring chain....


I think the ek company sold the first o ring chain in the 70's/

  • tribalbc

Posted October 03, 2009 - 07:05 PM

#22

I think the ek company sold the first o ring chain in the 70's/


We have a winner :banana:

So I googled EK chains, there a Japanese company, so that fits (says Japan on chain links in pics)
They introduced the first o-ring chain in 1974 :banana:
They started doing the drilled out inner plate in 1980 they claim a 20g weight loss over 100 links and better cooling of the chain....

So it sounds like EK it is.

Now has anyone ever tried anEK chain :busted:



http://www.ekchain.com/company.htm

  • grayracer513

Posted October 03, 2009 - 09:02 PM

#23

They started doing the drilled out inner plate in 1980 they claim a 20g weight loss over 100 links

Am I the only one who converted that to ounces?

It failed to impress me.

  • tribalbc

Posted October 03, 2009 - 09:37 PM

#24

Am I the only one who converted that to ounces?

It failed to impress me.


Yeah that's less than an ounce. Wasn't impressed, just stating their facts.
I don't think the x-ring has the holes anyways :busted:

Still just trying to figure out if it's a quality chain for $60......

  • RCannon

Posted October 04, 2009 - 07:10 AM

#25

We have a winner :banana:

So I googled EK chains, there a Japanese company, so that fits (says Japan on chain links in pics)
They introduced the first o-ring chain in 1974 :banana:
They started doing the drilled out inner plate in 1980 they claim a 20g weight loss over 100 links and better cooling of the chain....

So it sounds like EK it is.

Now has anyone ever tried anEK chain :busted:



http://www.ekchain.com/company.htm


I actually remember buying one back in the late 70's. The o ring chain sounded like such a good idea back then. It was a great chain, but I dont know how much that means 30 years later.

  • meyer1son

Posted October 12, 2009 - 09:26 AM

#26

I bought the GDX X-ring gold colored chain. I like the thought of yamaha accessories because they are quality and well priced compared to having ten other brands of accessories. It might be more the thought of having yamaha stuff then other that I like



So how's it holding up?

  • harrperf

Posted October 12, 2009 - 08:58 PM

#27

Your comment pertaining to 3-5 grams worth 500 rpm... is below

Sorry, that's an exaggeration.



wow quick to pounce!



Hmmm...
Well, I am not going to type out all the math here...but here are two links that can help

http://www.tech.plym...tes/valvet1.htm

http://www.thumperta...ad.php?t=717160

lets assume a total valve train weight of 60 grams per valve (retainers, valve, bucket, percentage of spring and keepers) and for the 'improved' valve train a weight of 57 grams (3 grams savings)



I have actually read through jesse's post...and there are some errors...which I may email him to ask about. First...kg*m/s^2 = newtons...not kilo newtons!

Second, I don't know where he comes up with 3.556m/s acceleration..first because it needs to be 3.556m/s^2 to be an accleration (let's assume typo with units...) and seconds because the real value is MUCH higher...as detailed in the first link I posted.

So using the first link posted...and assuming simple harmonic motion as it details (which for this stupid post of mine is a fair assumption to represent valve train motion) I personally came up with 2261m/s^2 peak acceleration.

That uses a valve lift of 5mm, a peak RPM window of 13000 RPM (little high for 450....little low for 250!) and cam duration of 260 degrees of possible 360 for a ratio of .72:1 for cam opening out of 1 revolution.

In that case...I get
135 newtons of force for 60 gram valve train

and

128 newtons force for 57 gram valve train

That's a 5.18 percent reduction in force required to actuate the valve train...which is also 5 percent lighter!

So...now let's assume new RPM window of 13500 RPM
The peak acceleration is now 2405m/s^2

The new Forces are
60g = 144 N
57G = 137N

Using the same valve springs...the difference in force between the 3 gram lighter valve train at 13500 RPM vs the heavier valve train at 13000 RPM is 2N...which means I lied a little...maybe only 400 RPM on the top end! at 5 grams...easily 500 RPM.

And I'm spent!

  • FinchFan194

Posted October 12, 2009 - 09:06 PM

#28

Yeah that's less than an ounce. Wasn't impressed, just stating their facts.
I don't think the x-ring has the holes anyways :bonk:

Still just trying to figure out if it's a quality chain for $60......


My RK xring has holes just like the GYTR on the inner plates so that could be Yamaha's source for the chain. My RK was about $80 or $90 and it stretched twice and hasn't moved much since. So if that is the source its a good chain for the price.

  • grayracer513

Posted October 13, 2009 - 09:03 AM

#29

Using the same valve springs...the difference in force between the 3 gram lighter valve train at 13500 RPM vs the heavier valve train at 13000 RPM is 2N...which means I lied a little...maybe only 400 RPM on the top end! at 5 grams...easily 500 RPM.

And I'm spent!

This is an interesting, and somewhat informative, but basic and limited theoretical analysis. First, the technical analysis was done for the purpose of determining the spring force required to control the valve train components at a given speed, not evaluate the effect that valve train weight has on parasitic losses within the engine. One oversight with regard to that is that the camshafts are driven at half speed, and thus the crankshaft has a 2:1 advantage over whatever drag there is at the cam.

Cam lift profiles, of course figure into this to a very great degree, as the author mentioned. Another point is that springs are chosen for their ability to control valve float. In order to do this, they must be able to overcome and reverse the moving mass of the entire valve train from lifter to valve, and hold it against the camshaft as its surface recedes from the tappet, matching the acceleration of the opening valve in reverse. If the cam is spun fast enough, the spring fails to stop or reverse the valve's motion, and a gap is left between the cam and follower. This is valve float, and at the point where this first occurs, net spring pressure against the the cam lobe is zero.

You, of course, knew that, and you may wonder why I mention it. The reason is that at all speeds lower than the point at which valve float sets in, the spring applies measurable pressure to the camshaft, both during valve opening and during closing.

At a near standstill, this force is equal on both sides of the cam (ignoring friction), and the valve spring that requires so much force to rotate the cam from closed valves to fully opened will then drive the cam from opened to closed with the same force, so there is no net loss of power. As the engine is run up in speed, the forces required to open the valves are increased by the greater acceleration rates required, and the driving effect of the springs on the cam is gradually reduced by the load placed on the springs in accelerating the valves back to their seats at higher rates, so the force required to rotate the cam naturally does increase as speeds increase.

But, at any speed lower than float, there is some spring pressure feeding energy back into the camshaft, reducing the net loss incurred by heavier springs. In a bench test of the stock YZ450 springs and valve train, float did not occur until the cam was turning 6800 RPM, which equates to a crankshaft speed of 13600 RPM, well beyond the rev limit of 11500, and far beyond the useful power range of even a modified YZ450. This means that there is yet another unconsidered reduction in the stated extra load placed on the engine by heavier valves.

Then, of course, there is the fact that you have chosen for your example a speed not attainable by a YZ450, and that the use of that speed exaggerates the effect of valve train load by (to simplify a complex trigonometric function somewhat) the square of the difference in speed. Even considering the 400 RPM difference you calculated within the true context of the article, the 2N load delta will be reduced tremendously by dropping from 13000 RPM, which is the high end of the rev range for a 250F, or the meat of things for an R6, to the more realistic ranges that engines in the bikes we talk about in this forum operate.

Then there is the more practical realm of empirical results. Engines I have personally built and tested have never shown significant losses or gains in power or RPM where the only change has been valve train weight or spring pressures.

So, based on these things, I still say your original statement was an exaggeration.

  • harrperf

Posted October 13, 2009 - 11:12 AM

#30

This is an interesting, and somewhat informative, but basic and limited theoretical analysis. First, the technical analysis was done for the purpose of determining the spring force required to control the valve train components at a given speed, not evaluate the effect that valve train weight has on parasitic losses within the engine. One oversight with regard to that is that the camshafts are driven at half speed, and thus the crankshaft has a 2:1 advantage over whatever drag there is at the cam.


It's accounted for.... I used 6500 actual cam RPM for 13000...and 6750 for 13500, along with (as stated) 260degrees cam duration of "possible" 360 (impossible..) though I am not calculating for parasitic loss in this...which is effects hp...but not usable rev range.

Cam lift profiles, of course figure into this to a very great degree, as the author mentioned.


Very true...the numbers for peak acceleration I used were very, very small compared to actual peak acceleration. The accelerations I did calculate, however, would correlate quite well at a critical point in a cam's motion. Right as it crosses over the "top" of it's lift...where most valve float occurs (well where most catastrophic valve float occurs.) Which you explain well below

Another point is that springs are chosen for their ability to control valve float. In order to do this, they must be able to overcome and reverse the moving mass of the entire valve train from lifter to valve, and hold it against the camshaft as its surface recedes from the tappet, matching the acceleration of the opening valve in reverse. If the cam is spun fast enough, the spring fails to stop or reverse the valve's motion, and a gap is left between the cam and follower. This is valve float, and at the point where this first occurs, net spring pressure against the the cam lobe is zero.



Accurate statement

You, of course, knew that, and you may wonder why I mention it. The reason is that at all speeds lower than the point at which valve float sets in, the spring applies measurable pressure to the camshaft, both during valve opening and during closing.

At a near standstill, this force is equal on both sides of the cam (ignoring friction), and the valve spring that requires so much force to rotate the cam from closed valves to fully opened will then drive the cam from opened to closed with the same force, so there is no net loss of power. As the engine is run up in speed, the forces required to open the valves are increased by the greater acceleration rates required, and the driving effect of the springs on the cam is gradually reduced by the load placed on the springs in accelerating the valves back to their seats at higher rates, so the force required to rotate the cam naturally does increase as speeds increase.

But, at any speed lower than float, there is some spring pressure feeding energy back into the camshaft, reducing the net loss incurred by heavier springs. In a bench test of the stock YZ450 springs and valve train, float did not occur until the cam was turning 6800 RPM, which equates to a crankshaft speed of 13600 RPM, well beyond the rev limit of 11500, and far beyond the useful power range of even a modified YZ450.


Maybe your modified 450! Listen to reed's zooki during last years supercross season. It revs very, very high!

This means that there is yet another unconsidered reduction in the stated extra load placed on the engine by heavier valves.

Then, of course, there is the fact that you have chosen for your example a speed not attainable by a YZ450, and that the use of that speed exaggerates the effect of valve train load by (to simplify a complex trigonometric function somewhat) the square of the difference in speed. Even considering the 400 RPM difference you calculated within the true context of the article, the 2N load delta will be reduced tremendously by dropping from 13000 RPM, which is the high end of the rev range for a 250F, or the meat of things for an R6, to the more realistic ranges that engines in the bikes we talk about in this forum operate.

Then there is the more practical realm of empirical results. Engines I have personally built and tested have never shown significant losses or gains in power or RPM where the only change has been valve train weight or spring pressures.

So, based on these things, I still say your original statement was an exaggeration.


I can not agree to any extent to this last paragraph.
Would lowering valve train weight improve power??? Not really. I didn't say it would...
Will it allow a higher rev ceiling? Most certainly. For many race engines...it's not just the power it makes...but for how long it makes it. Even MORE importantly for mx...is the usable range of 1 gear. If a rider can hang a gear longer without a shift in critical areas of the track...he can go faster, or jump a tricky jump that would otherwise require a shift on the face.

If I redo the calculations...and use 10000 RPM as my numbers...I get a similar answer...certainly not quite as optimistic, but instead of 3 grams savings if I use 5...the answer remains true.

A motor that revs longer allows more usable power...and often for the best riders out there...power when they need it most! Just think if of a couple injuries in supercross this past year due to mistaken gear choice before a tripple...and they are commited too much to not go for it. Had the engine revd just that much further without hitting the rev limiter...they MAYBE would have made it. As a rider...I would be all for that. As an engine builder...wouldn't you want your stuff to rev further reliably?

The quickest solution to solving valve train instability at high RPM is less weight. More spring force opens a can of worms that isn't fun...and at some point no spring force is practically possible to overcome the mass of a valve train.

Anyways, my original statement was the importance of dynamic mass. In saying so..I used an "extreme" but true statement that 3-5grams could extend 500 RPM of usable power...

Whatever...the pissing match can continue...or we can all agree that a chain with holes in it, looks cool to some people..probably doesn't improve performance, and is priced fairly high for a chain.:bonk:

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  • grayracer513

Posted October 13, 2009 - 12:08 PM

#31

As an engine builder...wouldn't you want your stuff to rev further reliably?

The quickest solution to solving valve train instability at high RPM is less weight. ....

Since it now runs to the rev limit reliably, and the valve train is stable 2000 RPM beyond that, it isn't something that keeps me awake.

Anyways, my original statement was the importance of dynamic mass. In saying so..I used an "extreme" but true statement that 3-5grams could extend 500 RPM of usable power...

If that was what you intended, your original statement:

People save 3-5 grams on a valve retainer and gain 500 RPM reliably...

...had a different ring to it. It's also still arguable that any such reduction in weight adds any usable power in the absence of any previous valve train instability.

...or we can all agree that a chain with holes in it, looks cool to some people..probably doesn't improve performance,...

It does look cool, and at a weight reduction of .20 ounce, I think it's safe to say it won't be noticed, yes.

  • harrperf

Posted October 13, 2009 - 02:36 PM

#32

Since it now runs to the rev limit reliably, and the valve train is stable 2000 RPM beyond that, it isn't something that keeps me awake.

If that was what you intended, your original statement:
...had a different ring to it. It's also still arguable that any such reduction in weight adds any usable power in the absence of any previous valve train instability.

It does look cool, and at a weight reduction of .20 ounce, I think it's safe to say it won't be noticed, yes.


wow you dont stop!

I guess I dont intend all my statements for "your" motor. Some users run new cams...where stock valve springs and/or weight saving measures must be used...
and some run ignitions where the rev limit is altered...

Of course I guess none of that matters for you or your sleep!

  • grayracer513

Posted October 13, 2009 - 02:46 PM

#33

wow you dont stop!

And you?

  • harrperf

Posted October 13, 2009 - 06:50 PM

#34

And you?


never!

It seems.... to quote the latest batman

that we are destined to do this forever...it's what happens when an immovable object meets and unstoppable force...

Best quote movie or not I have heard in a long time.

  • grayracer513

Posted October 13, 2009 - 09:18 PM

#35

Best quote movie or not I have heard in a long time.

I can't agree with that, either. You don't seem surprised.

One of mine is...

I'm your huckleberry!


Posted Image

:bonk:

  • TDW

Posted December 11, 2009 - 05:38 PM

#36

Was hoping to find out how wide the 520 GDXL xring chain is. Tried to find out thru a dealer and then yamaha customer service, neither could find a spec or could measure one. Would appreciate it if anybody who has one could help out. Thanks

  • tribalbc

Posted December 11, 2009 - 06:10 PM

#37

Was hoping to find out how wide the 520 GDXL xring chain is. Tried to find out thru a dealer and then yamaha customer service, neither could find a spec or could measure one. Would appreciate it if anybody who has one could help out. Thanks


I ended up getting the 520 GDX. It was such a deal I had to try it. I know that's a wider version than the one you're wanting specs on but I could measure it.

Chains still new uninstalled so can't comment on quality. Cold and lots of snow here :banghead:

  • FinchFan194

Posted December 11, 2009 - 06:12 PM

#38

I can't agree with that, either. You don't seem surprised.

One of mine is...



Posted Image

:banghead:


Isn't it "I'm here huckleberry":moon:

  • TDW

Posted December 11, 2009 - 07:15 PM

#39

I ended up getting the 520 GDX. It was such a deal I had to try it. I know that's a wider version than the one you're wanting specs on but I could measure it.

Chains still new uninstalled so can't comment on quality. Cold and lots of snow here :banghead:


Be great if you could measure the outer plates side to side. I dont know for sure what the difference between the GDX and GDXL is for sure, both are Xring chains. Maybe the XL has the extra holes in the side plates to get it lighter?

  • tribalbc

Posted December 11, 2009 - 08:33 PM

#40

Be great if you could measure the outer plates side to side. I dont know for sure what the difference between the GDX and GDXL is for sure, both are Xring chains. Maybe the XL has the extra holes in the side plates to get it lighter?


The XL is a little narrower than the X for bikes with less clearance and not quite as strong. My X has the holes as well (not that I think they do anything)

So my X outside of pin to outside of pin (widest spot) is 20mm. All I can say is the XL will be narrower than that.





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