Power Valve Cylinders for Banshee
#1
02-18-2000, 04:11 PM
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#2
02-19-2000, 05:44 AM
#4
02-19-2000, 09:04 PM
#5
02-22-2000, 12:33 AM
The one major downfall of the RZ cylinder that I can think of is it's decided lack of coolant passages over/around the exhaust port/outlet.
I work with a gentleman that was the '98 Int. Kart Fed. Champ in the RZ350 class. So I've had the opportunity to deal with the RZ motor and the Banshee motor both in hi-perf applications.
The RZ cylinder has the same general port layout as the Banshee, however the port timings differ . Typically the peak power RPM of an RZ based cylinder are higher than that of most Banshee's. Most in chassis pipe designs for Banshees simply can't produce decent power figures at those RPM's. Another note is that the RZ cylinders use studs to mount the pipe, vice the spigot and o-ring set-up found on Banshee's, so some fabrication is in order to utilize Banshee pipes.
I think for the hassle and fabrication involved RZ cylinders aren't worth it. My view is, that if RZ cylinders were the hot set-up every race shop and hot shot hillshooter would reccomend them. You simply don't see that.
However, the RZ tranny does offer some very nice characteristics for hillshooting and drag racing.
Side note--Just got back from the dunes at Florence, whatta weekend!!!! Sore for work tommorrow!!!!
I work with a gentleman that was the '98 Int. Kart Fed. Champ in the RZ350 class. So I've had the opportunity to deal with the RZ motor and the Banshee motor both in hi-perf applications.
The RZ cylinder has the same general port layout as the Banshee, however the port timings differ . Typically the peak power RPM of an RZ based cylinder are higher than that of most Banshee's. Most in chassis pipe designs for Banshees simply can't produce decent power figures at those RPM's. Another note is that the RZ cylinders use studs to mount the pipe, vice the spigot and o-ring set-up found on Banshee's, so some fabrication is in order to utilize Banshee pipes.
I think for the hassle and fabrication involved RZ cylinders aren't worth it. My view is, that if RZ cylinders were the hot set-up every race shop and hot shot hillshooter would reccomend them. You simply don't see that.
However, the RZ tranny does offer some very nice characteristics for hillshooting and drag racing.
Side note--Just got back from the dunes at Florence, whatta weekend!!!! Sore for work tommorrow!!!!
#7
02-29-2000, 03:07 AM
RZ top end conversions.
OK I have had an opportunity to measure up both a stock Banshee and stock RZ cylinder and will answer a lot of questions. I very good friend of mine runs a long rod 400cc RZ cylindered Banshee which is a devastingly fast machine.......
1) Firstly the RZ 350 was only made for 4 years, 83 to 86 and was very rare in the US due to EPA restrictions. Parts are avaiable and will bolt stright on. How many of you have even heard of an RZ 350 ??? let alone know that it had a powervalve engine rated at:
US version 49 hp at the crank, they had cat convertors, gag.....
Non US 59 HP at the crank.
Toomey make pipes that add 15 HP to the US version,
2) The setup is very very effective, and is a common mod down here in New Zealand, all the top race banshees run RZ top ends, THEY WORK. An RZ powervalve Banhsee will out torque a ported non powervalve banshee any time. Both Toomey T5's and FMF fattys work great on the RZ cylinders. Staurt Toomeys comment is that you have to add 25mm to the RZ port via a stub unit to get the expansion length right, I could see if you ran them straight on that the pipes tuned length would be up the spout so to say.....
3) PORT TIMING. With the powervalve closed the exhaust port height is the same or possibly up to One mm lower than the standard Banshee layout, hardly radical is it ??. Between 5500 and 6000 rpm the powervalve starts to opens, full open the port is 3 to 3.5 mm higher than a stock Banshee port, man this allows these engines to sing up into the higher rpms with a smooth easy pull rather than an all or nothing "hit"
This really smoothes out the midrange, these engines are way more tractable than ported shee setups.
4) With the powervalves switched of the Banshee is a real short shifter, they go flat as at about 7000 rpm and won't rev, If they stick open it's clutch city - no midrange. Switched on and tied into the ignition as per the stock RZ setup you get the same top end as a fully ported to the eyeballs barrell and have the same or better midrange pull of a stocker. There is an aftermarket controller box available ex the UK which allows you to alter the powervalve timing to suit your porting if you want.
5) The powervalve settings are easily adjustable so you could retard the top end timing if you wanted for say more tighter riding conditions and actually retard the exhaust timing to below stock banshee spec's and aviod the mad "rush" in the midrange.
6) the RZ trans ratios are no good off road, first is way to fast, second through 5 are supposed to be the same ?? and 6th supposedly slower (gotta get those little Banshee wheels whizzing around).
I haven't counted the teeth on gear sets so can't confirm for sure. Why buy a whole engine when you just need the top end and ignition ??
7) You need the RZ ignition, this is a bonus for duners as it has a built in battery changing system, perfect for running those trick arc ignition lights which need a battery. The battery can be tucked in up front out of harms way and helps keep the front end down. Yes there a few more bits to mount, an extra black box and servo motor for the powervalves.
8) Cooling, the RZ has bigger jackets all the way around and flows a considerable amount of volume around the top of the powervalve set up. None of the racers I know using this setup have had overheating problems or burn't powervalves. If your having problems I'd look at your porting layout. These engines have been extensively road raced all over the world and are pretty damn reliable.
You have to use the RZ head to match the cylinder jackets around the powervalves.
Just because it's not a regular sight doesn't mean it doesn't work, the RZ is a better mouse trap for sure, NO MAJOR manufacturer turns out MX bikes without powervalves these days, why because you always can get more midrange grunt with some sort of exhaust control nechanism. Finding the parts second hand is the trick as new price from Yamaha are "out there......" and they are rare in the US, DOWN IN nz a lot of em have been simply thrown way...... as "old stuff".........
10) As a further spanner in the works, did you know that an 87 / 88 RM cylinder is a straight Bolt on for an LT250R, have a look at both and see which one you'd rather run......
I will be posting a set of photographs on my web site within the next TWO TO THREE DAYS days showing views of the RZ vs Banshee cylinders, tune in too:
http://homepages.ihug.co.nz/~crainic/INDEX.htm
Hope this sets a few facts straight on this.
Craig Ridgley
OK I have had an opportunity to measure up both a stock Banshee and stock RZ cylinder and will answer a lot of questions. I very good friend of mine runs a long rod 400cc RZ cylindered Banshee which is a devastingly fast machine.......
1) Firstly the RZ 350 was only made for 4 years, 83 to 86 and was very rare in the US due to EPA restrictions. Parts are avaiable and will bolt stright on. How many of you have even heard of an RZ 350 ??? let alone know that it had a powervalve engine rated at:
US version 49 hp at the crank, they had cat convertors, gag.....
Non US 59 HP at the crank.
Toomey make pipes that add 15 HP to the US version,
2) The setup is very very effective, and is a common mod down here in New Zealand, all the top race banshees run RZ top ends, THEY WORK. An RZ powervalve Banhsee will out torque a ported non powervalve banshee any time. Both Toomey T5's and FMF fattys work great on the RZ cylinders. Staurt Toomeys comment is that you have to add 25mm to the RZ port via a stub unit to get the expansion length right, I could see if you ran them straight on that the pipes tuned length would be up the spout so to say.....
3) PORT TIMING. With the powervalve closed the exhaust port height is the same or possibly up to One mm lower than the standard Banshee layout, hardly radical is it ??. Between 5500 and 6000 rpm the powervalve starts to opens, full open the port is 3 to 3.5 mm higher than a stock Banshee port, man this allows these engines to sing up into the higher rpms with a smooth easy pull rather than an all or nothing "hit"
This really smoothes out the midrange, these engines are way more tractable than ported shee setups.
4) With the powervalves switched of the Banshee is a real short shifter, they go flat as at about 7000 rpm and won't rev, If they stick open it's clutch city - no midrange. Switched on and tied into the ignition as per the stock RZ setup you get the same top end as a fully ported to the eyeballs barrell and have the same or better midrange pull of a stocker. There is an aftermarket controller box available ex the UK which allows you to alter the powervalve timing to suit your porting if you want.
5) The powervalve settings are easily adjustable so you could retard the top end timing if you wanted for say more tighter riding conditions and actually retard the exhaust timing to below stock banshee spec's and aviod the mad "rush" in the midrange.
6) the RZ trans ratios are no good off road, first is way to fast, second through 5 are supposed to be the same ?? and 6th supposedly slower (gotta get those little Banshee wheels whizzing around).
I haven't counted the teeth on gear sets so can't confirm for sure. Why buy a whole engine when you just need the top end and ignition ??
7) You need the RZ ignition, this is a bonus for duners as it has a built in battery changing system, perfect for running those trick arc ignition lights which need a battery. The battery can be tucked in up front out of harms way and helps keep the front end down. Yes there a few more bits to mount, an extra black box and servo motor for the powervalves.
8) Cooling, the RZ has bigger jackets all the way around and flows a considerable amount of volume around the top of the powervalve set up. None of the racers I know using this setup have had overheating problems or burn't powervalves. If your having problems I'd look at your porting layout. These engines have been extensively road raced all over the world and are pretty damn reliable.
You have to use the RZ head to match the cylinder jackets around the powervalves.
Just because it's not a regular sight doesn't mean it doesn't work, the RZ is a better mouse trap for sure, NO MAJOR manufacturer turns out MX bikes without powervalves these days, why because you always can get more midrange grunt with some sort of exhaust control nechanism. Finding the parts second hand is the trick as new price from Yamaha are "out there......" and they are rare in the US, DOWN IN nz a lot of em have been simply thrown way...... as "old stuff".........
10) As a further spanner in the works, did you know that an 87 / 88 RM cylinder is a straight Bolt on for an LT250R, have a look at both and see which one you'd rather run......
I will be posting a set of photographs on my web site within the next TWO TO THREE DAYS days showing views of the RZ vs Banshee cylinders, tune in too:
http://homepages.ihug.co.nz/~crainic/INDEX.htm
Hope this sets a few facts straight on this.
Craig Ridgley
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#8
02-29-2000, 12:01 PM
Certaintly all valid and obviously investigated and proven points. It's been far too long since we've been blessed with some good techincal discussions. So please view as that, a in-depth discussion into this.
I couldn't agreee more that a power-valved Banshee motor would out torque most, if not any, other Banshee motor.
Addressing the tuned length of the pipe, matters. 25mm of tuned length means alot. The in-chassis pipes are at an disadvantage already, cutting them shorter would hurt even more. Most in-chassis pipes cannot produce respectible power figures above 9000 RPM's, not in comparason to what a "hotter" pipe design can.
The issue of port timing directly ties back in with the tuned length issue.
Most local engine builders around these parts usually cut thier "hotter" motors exh. roove up 2mm. That is what works best.
I've got to throw in this disclaimer, I am a avid sand dune rider, and taper alot of my intentions towards that, especially hill-racing. So please keep that in mind, I'm not trying to put together "trail" Banshee's.
With the exh. opening another 3.5mm at peak power the duration becomes incredibly loner, so goes for the blowdown durations. However the mean effective power stroke becomes lower. Obviously it all adds up and work out in the end. But....back to the tuned length issue. With exh. durations that high, you're going to be hard pressed to make decent power figures with in-chassis pipes. That is why most serious built hillshooter motors utilize drag-pipes/side-pipes". Not only to get a decent length but also pipe volume as well. To me it simply doesn't live up to it's potential and why all the hassle then??
The cooling issue is second hand info for me. The IKF guy I mentioned has told me on several occasions that most of thier racers look to go to Banshee cylinders. Also that could be that most of them disable the powervalves, for what reason, I'll have to ask them.
The transmission gear ratios are different. I've transplanted 2 trannies now. Typically with 20" tires gearing winds up around 16/43. 1st, 2nd, and 3rd gears are close ratio, 4th is wider out, same with 5th, then 6th is close to 5th. Each time we have set these up we gear for a 1st gear launch, ultimately winding up in 3rd gear by the end of the hill/drag. We did try a set-up for 2nd gear launches, which seemed to work well for shorter hills, with only 1 shift needed, but it seemed to us defeating the purpose of the RZ tranny, other than only needing one shift which was nice. After installing the RZ tranny, the first pass I made on his Banshee I came across the top of the hill faster than I had ever before, and there were no other changes other than the tranny. Simply put it works GREAT for hillracing in the dunes.
On paper it seems to me that the RZ cylinder would be the choice in buidling stout motors. However, you mentioned that there are lots of parts floating around for sale in N.Z. I have been hard pressed to find cylinder heads and transmissions to transplant. If I do find them in the US, it's big bucks. I would like to have an RZ to ride back and forth to work when the weather permits. It would seem so cool to be able to hop on a Banshee and then hop on an RZ to ride to work. The nice powerband hit while rippin' down the freeway would sure seem nice.
The addition of the associated components to make the powervalve system work adds weight. People spend thousands of dollars trying to get rid of weight. (Lonestar chassis, billet parts, and so on.)
There are so many things that would make the RZ swap seem logical, it does make sense, but I think for the hassle and fabrication, I'll still take a plain old Banshee motor. The short comings of a Banshee motor can be altered with the state of tune for far less hassle than a RZ top-end transplant.
Now a TZ swap....hmmmmm...got any TZ750 parts down under???
I couldn't agreee more that a power-valved Banshee motor would out torque most, if not any, other Banshee motor.
Addressing the tuned length of the pipe, matters. 25mm of tuned length means alot. The in-chassis pipes are at an disadvantage already, cutting them shorter would hurt even more. Most in-chassis pipes cannot produce respectible power figures above 9000 RPM's, not in comparason to what a "hotter" pipe design can.
The issue of port timing directly ties back in with the tuned length issue.
Most local engine builders around these parts usually cut thier "hotter" motors exh. roove up 2mm. That is what works best.
I've got to throw in this disclaimer, I am a avid sand dune rider, and taper alot of my intentions towards that, especially hill-racing. So please keep that in mind, I'm not trying to put together "trail" Banshee's.
With the exh. opening another 3.5mm at peak power the duration becomes incredibly loner, so goes for the blowdown durations. However the mean effective power stroke becomes lower. Obviously it all adds up and work out in the end. But....back to the tuned length issue. With exh. durations that high, you're going to be hard pressed to make decent power figures with in-chassis pipes. That is why most serious built hillshooter motors utilize drag-pipes/side-pipes". Not only to get a decent length but also pipe volume as well. To me it simply doesn't live up to it's potential and why all the hassle then??
The cooling issue is second hand info for me. The IKF guy I mentioned has told me on several occasions that most of thier racers look to go to Banshee cylinders. Also that could be that most of them disable the powervalves, for what reason, I'll have to ask them.
The transmission gear ratios are different. I've transplanted 2 trannies now. Typically with 20" tires gearing winds up around 16/43. 1st, 2nd, and 3rd gears are close ratio, 4th is wider out, same with 5th, then 6th is close to 5th. Each time we have set these up we gear for a 1st gear launch, ultimately winding up in 3rd gear by the end of the hill/drag. We did try a set-up for 2nd gear launches, which seemed to work well for shorter hills, with only 1 shift needed, but it seemed to us defeating the purpose of the RZ tranny, other than only needing one shift which was nice. After installing the RZ tranny, the first pass I made on his Banshee I came across the top of the hill faster than I had ever before, and there were no other changes other than the tranny. Simply put it works GREAT for hillracing in the dunes.
On paper it seems to me that the RZ cylinder would be the choice in buidling stout motors. However, you mentioned that there are lots of parts floating around for sale in N.Z. I have been hard pressed to find cylinder heads and transmissions to transplant. If I do find them in the US, it's big bucks. I would like to have an RZ to ride back and forth to work when the weather permits. It would seem so cool to be able to hop on a Banshee and then hop on an RZ to ride to work. The nice powerband hit while rippin' down the freeway would sure seem nice.
The addition of the associated components to make the powervalve system work adds weight. People spend thousands of dollars trying to get rid of weight. (Lonestar chassis, billet parts, and so on.)
There are so many things that would make the RZ swap seem logical, it does make sense, but I think for the hassle and fabrication, I'll still take a plain old Banshee motor. The short comings of a Banshee motor can be altered with the state of tune for far less hassle than a RZ top-end transplant.
Now a TZ swap....hmmmmm...got any TZ750 parts down under???
#9
03-01-2000, 02:02 AM
Back country, hope you don't mind, i've edited answers to your points.
Addressing the tuned length of the pipe, matters. 25mm of tuned length means alot. The in-chassis pipes are at an disadvantage already, cutting them shorter would hurt even more.
Stuart Toomeys advice was that you need a 25 mm long spigot in order to get the T5's "correct"
Use the pipes to get great midrange and the power valves to increase top end, any pipe design is always a compromise......
Most local engine builders around these parts usually cut thier "hotter" motors exh. roove up 2mm. That is what works best.
OK, the RZ then open up another 1.5 on top of that. Same midrange, more top end Win Win.....
With the exh. opening another 3.5mm at peak power the duration becomes incredibly loner, so goes for the blowdown durations. However the mean effective power stroke becomes lower. Obviously it all adds up and work out in the end. But....back to the tuned length issue. With exh. durations that high, you're going to be hard pressed to make decent power figures with in-chassis pipes.
OK, my buddy Graham has a fully built Duncan Banshee engine, this hauls but he reckons the RZ easily outruns it especailly once the terrian opens up, the RZ is far stronger on top. this engine runs T5's. Seems to work devastingly well......
That is why most serious built hillshooter motors utilize drag-pipes/side-pipes". Not only to get a decent length but also pipe volume as well. To me it simply doesn't live up to it's potential and why all the hassle then??
More midrange HP for any given compariable exhaust port configuration with the powervalve open.
Also that could be that most of them disable the powervalves, for what reason, I'll have to ask them.
Most road race porting setups are so highly cut there is nothing left of the power valve unit and heck they don't care about HP at 5000rpm, it's to low in the range for these 12,000 rpm rockets....... the powervalve was really aimed at strong street manners.
Purpose built Road race engines with power valves have a lot more open close range, some of the Rotax units can raise lower the exhaust port height by 6mm, now if this wasn't an advantage why would they do it ?? More torque off the corners.......
On paper it seems to me that the RZ cylinder would be the choice in buidling stout motors. However, you mentioned that there are lots of parts floating around for sale in N.Z. I have been hard pressed to find cylinder heads and transmissions to transplant. If I do find them in the US, it's big bucks.
probably do an entire engine for about US$750 ???
let me know if you want a tranny......... and I'll sort a price.......
I would like to have an RZ to ride back and forth to work when the weather permits. It would seem so cool to be able to hop on a Banshee and then hop on an RZ to ride to work. The nice powerband hit while rippin' down the freeway would sure seem nice.
The addition of the associated components to make the powervalve system work adds weight. People spend thousands of dollars trying to get rid of weight. (Lonestar chassis, billet parts, and so on.)
Maybe 8 pounds total ?? If most of us went on a diet it would be more productive.......
There are so many things that would make the RZ swap seem logical, it does make sense, but I think for the hassle and fabrication, I'll still take a plain old Banshee motor. The short comings of a Banshee motor can be altered with the state of tune for far less hassle than a RZ top-end transplant.
Sorry can't agree with you there.........
How do you get more midrange HP out of a Banshee and 20 % more top end ?? that runs on normal gas and isn't bored & stroked to the eyeballs, not cheap mods those.......
Now a TZ swap....hmmmmm...got any TZ750 parts down under???
Rare as Rockin horse dodo............
Craig
Addressing the tuned length of the pipe, matters. 25mm of tuned length means alot. The in-chassis pipes are at an disadvantage already, cutting them shorter would hurt even more.
Stuart Toomeys advice was that you need a 25 mm long spigot in order to get the T5's "correct"
Use the pipes to get great midrange and the power valves to increase top end, any pipe design is always a compromise......
Most local engine builders around these parts usually cut thier "hotter" motors exh. roove up 2mm. That is what works best.
OK, the RZ then open up another 1.5 on top of that. Same midrange, more top end Win Win.....
With the exh. opening another 3.5mm at peak power the duration becomes incredibly loner, so goes for the blowdown durations. However the mean effective power stroke becomes lower. Obviously it all adds up and work out in the end. But....back to the tuned length issue. With exh. durations that high, you're going to be hard pressed to make decent power figures with in-chassis pipes.
OK, my buddy Graham has a fully built Duncan Banshee engine, this hauls but he reckons the RZ easily outruns it especailly once the terrian opens up, the RZ is far stronger on top. this engine runs T5's. Seems to work devastingly well......
That is why most serious built hillshooter motors utilize drag-pipes/side-pipes". Not only to get a decent length but also pipe volume as well. To me it simply doesn't live up to it's potential and why all the hassle then??
More midrange HP for any given compariable exhaust port configuration with the powervalve open.
Also that could be that most of them disable the powervalves, for what reason, I'll have to ask them.
Most road race porting setups are so highly cut there is nothing left of the power valve unit and heck they don't care about HP at 5000rpm, it's to low in the range for these 12,000 rpm rockets....... the powervalve was really aimed at strong street manners.
Purpose built Road race engines with power valves have a lot more open close range, some of the Rotax units can raise lower the exhaust port height by 6mm, now if this wasn't an advantage why would they do it ?? More torque off the corners.......
On paper it seems to me that the RZ cylinder would be the choice in buidling stout motors. However, you mentioned that there are lots of parts floating around for sale in N.Z. I have been hard pressed to find cylinder heads and transmissions to transplant. If I do find them in the US, it's big bucks.
probably do an entire engine for about US$750 ???
let me know if you want a tranny......... and I'll sort a price.......
I would like to have an RZ to ride back and forth to work when the weather permits. It would seem so cool to be able to hop on a Banshee and then hop on an RZ to ride to work. The nice powerband hit while rippin' down the freeway would sure seem nice.
The addition of the associated components to make the powervalve system work adds weight. People spend thousands of dollars trying to get rid of weight. (Lonestar chassis, billet parts, and so on.)
Maybe 8 pounds total ?? If most of us went on a diet it would be more productive.......
There are so many things that would make the RZ swap seem logical, it does make sense, but I think for the hassle and fabrication, I'll still take a plain old Banshee motor. The short comings of a Banshee motor can be altered with the state of tune for far less hassle than a RZ top-end transplant.
Sorry can't agree with you there.........
How do you get more midrange HP out of a Banshee and 20 % more top end ?? that runs on normal gas and isn't bored & stroked to the eyeballs, not cheap mods those.......
Now a TZ swap....hmmmmm...got any TZ750 parts down under???
Rare as Rockin horse dodo............
Craig
#10
03-01-2000, 03:10 AM