Anyone seen a review of it yet ?
TM bets on an electronic PV.
Started by
Francisco
, Jun 10 2012 06:44 PM
6 replies to this topic
Posted 10 June 2012 - 06:48 PM
Isn't this the same thing as honda's RC valve. Electronic powervalve with a servo motor? Friend had an 02 250 honda with the RC valve and it got frozen up a few times at the servo motor... can somebody explain the benefits of it vs a traditional PV?
Posted 10 June 2012 - 09:45 PM
'87 Husky 250CR had an electric PV also......nothing new. Hard to see how it's an advantage.......KTM has perfected the PV with easily adjustable pre-load and softer/harder springs supplied w/bike. TM should be copying KTM, not Husky/Honda. Not that I wouldn't love to have a TM.........just sayin 
Posted 10 June 2012 - 09:50 PM
The benifits are/should be that the power valve will open in a more controled manner
If you take the average 2 sroke power valved engine and remove the powervalve cover and watch the linkage as you rev it they go from shut to fully open in a few 100rpms so basicly the cable aproach should give a wider / longer spread of power as the valve should only be open enough for arguements sake at 5000 rpm for optmum power at that rpm, same goes for 6000 rpm 7000 rpm ect ect , I think the system should work well if linked to the ignition / cdi but woulnt have a clue if it is lol
KTM ect use different spring rates to try and achieve the same sort of thing and can shift the power delivery across a fair range, so in therory if the cable set up has any form of adjustability you could make the valve open sooner or later depending on track / riding style
Must add this is only my personal take on the system and will quite happily be shot down in flames if I am off the mark a bit
If you take the average 2 sroke power valved engine and remove the powervalve cover and watch the linkage as you rev it they go from shut to fully open in a few 100rpms so basicly the cable aproach should give a wider / longer spread of power as the valve should only be open enough for arguements sake at 5000 rpm for optmum power at that rpm, same goes for 6000 rpm 7000 rpm ect ect , I think the system should work well if linked to the ignition / cdi but woulnt have a clue if it is lol
KTM ect use different spring rates to try and achieve the same sort of thing and can shift the power delivery across a fair range, so in therory if the cable set up has any form of adjustability you could make the valve open sooner or later depending on track / riding style
Must add this is only my personal take on the system and will quite happily be shot down in flames if I am off the mark a bit
Posted 11 June 2012 - 10:49 AM
dmm698, on 10 June 2012 - 06:48 PM, said:
Isn't this the same thing as honda's RC valve. Electronic powervalve with a servo motor? Friend had an 02 250 honda with the RC valve and it got frozen up a few times at the servo motor... can somebody explain the benefits of it vs a traditional PV?
What I like about them is simplicity. Just disconnect the cables and take the cylinder out.. no linkage to mess with.
It's not earth shaking technology just would like to know if, unlike honda, TM got it right..
Posted 17 June 2012 - 07:08 AM
I hear the new 125 TM's have more power than their last years 144 so I think it or something works. I also read it is adjustable. Sweet bikes and I'm glad they didn't just copy KTM.
Posted 17 June 2012 - 05:54 PM
johnnyboy, on 10 June 2012 - 09:50 PM, said:
The benifits are/should be that the power valve will open in a more controled manner
If you take the average 2 sroke power valved engine and remove the powervalve cover and watch the linkage as you rev it they go from shut to fully open in a few 100rpms so basicly the cable aproach should give a wider / longer spread of power as the valve should only be open enough for arguements sake at 5000 rpm for optmum power at that rpm, same goes for 6000 rpm 7000 rpm ect ect , I think the system should work well if linked to the ignition / cdi but woulnt have a clue if it is lol
KTM ect use different spring rates to try and achieve the same sort of thing and can shift the power delivery across a fair range, so in therory if the cable set up has any form of adjustability you could make the valve open sooner or later depending on track / riding style
Must add this is only my personal take on the system and will quite happily be shot down in flames if I am off the mark a bit
If you take the average 2 sroke power valved engine and remove the powervalve cover and watch the linkage as you rev it they go from shut to fully open in a few 100rpms so basicly the cable aproach should give a wider / longer spread of power as the valve should only be open enough for arguements sake at 5000 rpm for optmum power at that rpm, same goes for 6000 rpm 7000 rpm ect ect , I think the system should work well if linked to the ignition / cdi but woulnt have a clue if it is lol
KTM ect use different spring rates to try and achieve the same sort of thing and can shift the power delivery across a fair range, so in therory if the cable set up has any form of adjustability you could make the valve open sooner or later depending on track / riding style
Must add this is only my personal take on the system and will quite happily be shot down in flames if I am off the mark a bit
+1 ~ You are pretty much on track with how they operate.
The primary advantage of an electronically controlled PV is that you are no longer tied to engine RPM to open or close the PV. Throttle position, engine rpm, and even timing can all be factored in to deciding when the PV should open and even how much it should open. Think along the lines of a modern EFI map, their three deminsional not a simple 2D RPM vs. throttle position chart. A properly programmed Electronic PV (ePV ??) is definitely an advancement for two strokes.
When Honda first introduced it on the last generation CR it wasn't that good as basic things like cable stretch and PV open/close timing wasn't really optimized. In the last year or two it was starting to pay dividens. If TM did it right (as I expect they did) then they will have an advantage.
