YPVS Valve Opening Speed of Rotation....

General forum on engines, transmissions, gearing and modifications to each

Moderator: rztom

Post Reply
Message
Author
User avatar
WVWRZ500N
- - - - -
- - - - -
Posts: 967
Joined: Sat Nov 19, 2005 1:15 am
Location: Lee's Summit, MO
Contact:

YPVS Valve Opening Speed of Rotation....

#1 Post by WVWRZ500N » Mon May 22, 2017 1:50 pm

Hello Fellow Club Members and Future Members:

I've got a question that I'm beginning to mull over. I've been running The Beast around and have some question as to if the power valve is actually opening fully by the time the bike is accelerated past 2nd and even into 3rd gear. By the time 4th is geared I can certainly tell that the full power is coming on as the acceleration experienced is near twice that of the previous 3 gears. I'm ordering a camera to try and get some videos of this but that'll be a few weeks.

Has anyone else experienced anything like this? Is there any way to increase the rate of speed to which the power valve actually snaps open? I'll admit the electronics side of these machines is not my specialty and more like a weakness unless the typical problems.

Cross posting this for more help if you see it elsewhere on the board.

Thanks in advance for the input.
Regards,
Bill Wilson
Wilson Performance
Lee's Summit, MO
http://www.wilsonperformance.net
Member RZ500 Owners Group #573
816-377-3185
WVWRZ500N@aol.com

silverstrom
- - - - -
- - - - -
Posts: 3236
Joined: Sat Feb 04, 2012 7:36 am

Re: YPVS Valve Opening Speed of Rotation....

#2 Post by silverstrom » Mon May 22, 2017 2:08 pm

The valve will not "snap" open. To do so would be pointless unless you're chasing that light switch narrow powerband of non-YPVS bikes. The RZ500 has a fairly narrow operating range. The valves start to open at 6150 and are fully open at 7950. Compare that to the TZR 2MA/1KT which is 5850-10050 or the late model RZ350 at 6000-10200.

The powervalve servo gets its operating signal from the powervalve controller. If you want to change the opening range of the powervalves you need to alter the signal coming from the controller. To do that you can send the controller to Nick at Two Stroke Race Labs, or buy one from Zeeltronic. Both will let you select the begin to open point and the full open point. If you are looking for an extremely narrow window you can set both points very close together. I prefer the Two Stroke Race Lab option and the ability to simply move the 12 dip switches to get the RPM points needed.

User avatar
WVWRZ500N
- - - - -
- - - - -
Posts: 967
Joined: Sat Nov 19, 2005 1:15 am
Location: Lee's Summit, MO
Contact:

Re: YPVS Valve Opening Speed of Rotation....

#3 Post by WVWRZ500N » Mon May 22, 2017 10:59 pm

silverstrom wrote:The valve will not "snap" open. To do so would be pointless unless you're chasing that light switch narrow powerband of non-YPVS bikes. The RZ500 has a fairly narrow operating range. The valves start to open at 6150 and are fully open at 7950. Compare that to the TZR 2MA/1KT which is 5850-10050 or the late model RZ350 at 6000-10200.

The powervalve servo gets its operating signal from the powervalve controller. If you want to change the opening range of the powervalves you need to alter the signal coming from the controller. To do that you can send the controller to Nick at Two Stroke Race Labs, or buy one from Zeeltronic. Both will let you select the begin to open point and the full open point. If you are looking for an extremely narrow window you can set both points very close together. I prefer the Two Stroke Race Lab option and the ability to simply move the 12 dip switches to get the RPM points needed.
John,

I'm aware of all of that information but do appreciate the input. What I believe is happening is it is not opening fast enough to keep up with the RPMs gaining speed. The engine revs way too fast for the servo to keep up until about the end of 3rd gear. Like I mentioned before by the time you shift into 4th full port timing is open and it REALLY comes on. Was wondering if anyone has messed with speeding up the servo or if it can be done.

See this poor cell phone video to get an idea. Zero to 120mph in around 9 second give or take. I haven't done any tuning yet either.

https://youtu.be/Y0a435JS9J0" onclick="window.open(this.href);return false;
Regards,
Bill Wilson
Wilson Performance
Lee's Summit, MO
http://www.wilsonperformance.net
Member RZ500 Owners Group #573
816-377-3185
WVWRZ500N@aol.com

silverstrom
- - - - -
- - - - -
Posts: 3236
Joined: Sat Feb 04, 2012 7:36 am

Re: YPVS Valve Opening Speed of Rotation....

#4 Post by silverstrom » Tue May 23, 2017 1:26 am

I do see what you mean. The bike certainly isn't lacking in power, but at low RPM there is a brief delay in power delivery due to what you believe is the lag in the PV opening rate. I'm not sure you can get around that rate as the stock servo will only rotate so fast. Other than proper cable rigging and lubrication you are limited to what you have.

I'm not a tuner, but after watching your video I believe your valves are full open long before you get to 3rd gear. If they weren't, you wouldn't have the pull you have now.The valves do open pretty quickly in stock form. I'd say that well before you get out of 1st gear at 10,000 RPM your valves are wide open.

What gearing do you have now? I ask because a simple gearing change is worth trying. A 45 rear is not out of line. 1st gear is really long on the bike and a 45 rear will get you though the low RPM delay you have now. You will lose on the top end, but at silly speeds you shouldn't be doing anyway. What you gain on the bottom can be pretty amazing. The best way to avoid the low RPM lag is not be at low RPM.

I run a 45. The next build will run a 45.

The video suggests to me that your valves are working just fine. It's below the 6150 RPM point where your valves are still closed that you have a problem. Above 6150 it accelerates very, very well as the valves begin to open and very quickly go full open. Up to 6150 it is a bit of a let down. You want to get through that range faster. Gearing will do that. There is no harm in trying. You may be surprised.

The other possibility is that you are over-fueled at lower RPM. Ultimately a dyno is the best way to get the best results.

User avatar
WVWRZ500N
- - - - -
- - - - -
Posts: 967
Joined: Sat Nov 19, 2005 1:15 am
Location: Lee's Summit, MO
Contact:

Re: YPVS Valve Opening Speed of Rotation....

#5 Post by WVWRZ500N » Tue May 23, 2017 12:13 pm

silverstrom wrote:I do see what you mean. The bike certainly isn't lacking in power, but at low RPM there is a brief delay in power delivery due to what you believe is the lag in the PV opening rate. I'm not sure you can get around that rate as the stock servo will only rotate so fast. Other that proper cable rigging and lubrication you are limited to what you have.

I'm not a tuner, but after watching your video I believe your valves are full open long before you get to 3rd gear. If they weren't, you wouldn't have the pull you have now.The valves do open pretty quickly in stock form. I'd say that well before you get out of 1st gear at 10,000 RPM your valves are wide open.

What gearing do you have now? I ask because a simple gearing change is worth trying. A 45 rear is not out of line. 1st gear is really long on the bike and a 45 rear will get you though the low RPM delay you have now. You will lose on the top end, but at silly speeds you shouldn't be doing anyway. What you gain on the bottom can be pretty amazing. The best way to avoid the low RPM lag is not be at low RPM.

I run a 45. The next build will run a 45.

The video suggests to me that your valves are working just fine. It's below the 6150 RPM point where your valves are still closed that you have a problem. Above 6150 it accelerates very, very well as the valves begin to open and very quickly go full open. Up to 6150 it is a bit of a let down. You want to get through that range faster. Gearing will do that. There is no harm in trying. You may be surprised.

The other possibility is that you are over-fueled at lower RPM. Ultimately a dyno is the best way to get the best results.
John,

Thanks for that response. My contention is the delay in power as the engine quickly revs past the PV opening RPM and basically you never experience full port timing in 1st and 2nd gear. (Although this may be a blessing in disguise). Everything is fresh lubrication so not worried about that.

I'm running 16/42 gearing now. I don't want to sacrifice top end performance and ultimately make it a constant shifting machine. I tried that with my 350 once and hated it. Wouldn't run much over 100 and constantly shifting. It's already cruising at 70 hitting 6K RPM in 6th. Any lower gearing and I couldn't run on the highway without being in the lower end of the powerband.

I won't argue that it's a bit rich in the midrange but very responsive overall. I would however argue that a dyno will only show peak results at TP and RPM. This would then need to be verified on the track/street to determine if that is the best solution. I've met many racers that didn't like the finished product the dyno tuned bike gave them and their lap times showed it.

So it is your understanding that the PV servo can not be sped up from it's current cycle rate then?
Regards,
Bill Wilson
Wilson Performance
Lee's Summit, MO
http://www.wilsonperformance.net
Member RZ500 Owners Group #573
816-377-3185
WVWRZ500N@aol.com

silverstrom
- - - - -
- - - - -
Posts: 3236
Joined: Sat Feb 04, 2012 7:36 am

Re: YPVS Valve Opening Speed of Rotation....

#6 Post by silverstrom » Tue May 23, 2017 12:59 pm

WVWRZ500N wrote: So it is your understanding that the PV servo can not be sped up from it's current cycle rate then?
I don't know how to do it with the stock parts Bill. Talk to Borut and ask him if his controller will accelerate the servo rate.

The alternative is a different servo. Perhaps the EXUP servo is faster?

You may also try talking to Nick at Two Stroke Race Lab. If anyone would know how to accelerate the rate it would be him. That is his area of expertise.

MK
Posts: 487
Joined: Thu Mar 09, 2006 12:54 pm
Location: Germany
Contact:

Re: YPVS Valve Opening Speed of Rotation....

#7 Post by MK » Tue May 23, 2017 2:18 pm

Bill, you can try different servos that have different mechanical properties (i.e. transmission ratio between motor and pulley rotation).
The higher the ratio, the faster the actuation, but the less torque if the valves were stuck.

In my race RZ I'm using the RGV servo which does the test cycle much faster than the stock servo. So this will work for a 350. On the 500 you need to test if its strong enough for 4 cylinders.
Almost any modern big foulstroke has an exhaust flap that is servo actuated. In my VTR1000 I used Ducati Hypermotard an ZX10R. These can be made working, too.
Either with a Zeeltronic or Ignitech box.

Speeding up the servo could be done by hacking the controller software (basically the PID gain values). But even in the mentioned programmable boxes these parameters are not open for user settings.
If memory serves me right some of the Megasquirt guys did this and they mentioned fiddling with the controller parameters.
If you're interested, google servo controller and you'll find lots of examples on how to build & program these.
Bye
Martin

User avatar
WVWRZ500N
- - - - -
- - - - -
Posts: 967
Joined: Sat Nov 19, 2005 1:15 am
Location: Lee's Summit, MO
Contact:

Re: YPVS Valve Opening Speed of Rotation....

#8 Post by WVWRZ500N » Tue May 23, 2017 3:39 pm

MK wrote:Bill, you can try different servos that have different mechanical properties (i.e. transmission ratio between motor and pulley rotation).
The higher the ratio, the faster the actuation, but the less torque if the valves were stuck.

In my race RZ I'm using the RGV servo which does the test cycle much faster than the stock servo. So this will work for a 350. On the 500 you need to test if its strong enough for 4 cylinders.
Almost any modern big foulstroke has an exhaust flap that is servo actuated. In my VTR1000 I used Ducati Hypermotard an ZX10R. These can be made working, too.
Either with a Zeeltronic or Ignitech box.

Speeding up the servo could be done by hacking the controller software (basically the PID gain values). But even in the mentioned programmable boxes these parameters are not open for user settings.
If memory serves me right some of the Megasquirt guys did this and they mentioned fiddling with the controller parameters.
If you're interested, google servo controller and you'll find lots of examples on how to build & program these.
Martin,

Good info, thanks. I've also thought about machining a new pulley on the servo motor that has a cam grind so to speak so that it will accelerate it's opening with the same cycle. I'm all for a mechanical fix if I can avoid electronics.
Regards,
Bill Wilson
Wilson Performance
Lee's Summit, MO
http://www.wilsonperformance.net
Member RZ500 Owners Group #573
816-377-3185
WVWRZ500N@aol.com

MK
Posts: 487
Joined: Thu Mar 09, 2006 12:54 pm
Location: Germany
Contact:

Re: YPVS Valve Opening Speed of Rotation....

#9 Post by MK » Tue May 23, 2017 4:12 pm

I fear you'll need at least SOME electronics because if you just modify the transmission ratio you'll also modify the rotation angle (i.e. how deep the valve closes).
The only way out is a programmable box that can adjust the actuation rpms as well as the desired positions.

If you have a stock PV box to sacrifice you'll find this interesting:
http://l3s9113.zeus09.de/RD350/Manual_P ... cation.pdf" onclick="window.open(this.href);return false;
Bye
Martin

User avatar
kpke
Posts: 667
Joined: Tue Nov 30, 2010 9:54 pm
Location: Livermore, CA USA

Re: YPVS Valve Opening Speed of Rotation....

#10 Post by kpke » Wed May 24, 2017 12:07 pm

Hi Bill! :smt006

I can't help with your PV issue. Just a side note FYI, I am running 17 x 45. I don't know how that compares mathematically (looking at gearing commander). If memory serves me right I think I'm at about 6K or so at 65 mph.

Your bike sounds great. :smt016
Ken's Garage YouTube Channel :smt023
https://www.youtube.com/c/KensGarage1

1985 RZ500 (R6 suspension & body work)

Post Reply