Actually the Rotax powervalves are less modern than the "old" Yamaha YPVS. The rotax units are not nearly as compact as the YPVS, plus they are operated by exhaust pressure, not a processor and servo like the YPVS. If I had a choice I would go with the RZ set up. The RZ components are out there already unlike a Rotax powervalve Banshee. If you want Rotax powervalves, go get a 583, or 670 Rotax and put it in you Banshee, that's power!! I was considering the RZ cylinder thing and decided to put my money into handling instead of more power. All the power in the world means nothing if you can't use it. Later
eric

 

What did you do to improve the handling on your Banshee. I am considering getting another one for myself(wife rides a 98) but I don't like the way it corners and handles whoops. Is it fixable with A-arms and good(Axis,TCS,PEP) shocks?

 

Since I have an 89' I bought an ATV Racing weld in A arm conversion kit, and +2+1 arms. These arms use Hiem joints on the upper arm so you can adjust your camber and caster. This allows you to set it up like a 250R instead of the stock crap on the Banshee. This all allows for better woop performance and better flying characteristics. Add a -1 swingarm and it would be the icing on the cake, making it even closer to an R. Basically you are moving the center of gravity which helps if fly better. Going to the track right now, so gotta go. By the way the ATV Racing suspension set up is probably one of the best out, you can get it powder coated any color you want (basically) or bare (which costs a couple dollar less, or chromed. I am running Works dual rates with rezzy's. I talked to one of the engineers at works and he recommended dual rates for MX since you just go right through the softest rate on the triples. Unless you are a hardcore rider I would save my money and go with the works shocks. The PEP, TCS, ect., are great, but not needed for anybody but pro level riders (or people that are real close). I would also get a wider axle, I went with the durablue 2+2. It will cost you, but it is worth it to me. Good luck.
Eric

 

Kiwi-Craig,
The more you talk about this the better it sounds.I have recently had my banshee ported and added a set of K&N Filters along with a Shaved head and a set of FMF pipes. Now the bottom end leaves much to be desired. I was thinking that these RZ Cylinders Would be a good way to go. But I was wondering just how much better would the bottom end be. Also you said that It smoothed out the power delivery? Did you mean that it took out the banshees flat spots in the power,or that it smoothed out that hard hit when it comes on the pipe that always results in spinning wheels and not much foward motion. Well sorry for all the questions but I am really interested in trying this out.

 

Thanks for the info. I don't want to rush into getting a quad for myself because there is so much potenetial for new2001 models. If Kawi doesn't release anything good then it looks like a Banshee with those suspension mods, a 250r, or maybe a DS. If I buy shocks, I will probably go with the more expensive units as until just recently I raced some moto cross. Sold the KX500 due to injury and decided to get into quads. I never really paid much attention to the quad world until a few months ago and look at what I get into. Man it is tough to get good info on what works. It seems everybody wants to talk smack. My only experience with ATV's is my wife's Banshee and my 85 ATC 250R that I have had for a LONG time. Thanks for the info.

 

It smoothes the power delivery, my MX racing buddy (runs a full spec LRD 250 with all the goods) commented that Grahams RZ banshee is really torquey rather than the all or nothing hit. the powervalves allow more midrange torque deleivery so the whole thing smoothes out then just winds out hard on top.

 

Thanks for giving me all this information... But I've got a few more questions.

Can you get replacement parts for the powervalve and the electrical stuff required on the RZ? If something goes out, will my local yamaha shop be-able to order me the part, or will I be screwed?

Does anyone know of any motorcycle salvage yards that specialize in RZ's or is it just luck to find the pieces in decent shape?

Am I limited to what pistons I can run in the RZ? Do I have to go with RZ pistons, or can I get those vito's 6 horse pistons? or Would there be any signifigant power increase? What carbs work best with it? would 34mm carbs throw off the powervalve?

I'm in the process of rebuilding my 92 Banshee, and after reading about this, I'm seriously concidering doing it.

 

Yamaha RD 350 YPVS is what you need to find, There are lots of simularitys between that and the Banshee engine, Namely the hole bottom end is the same, Bar some gear wheels, although these are also very simular.. The only problem with fitting such an engine to your bike is.
1. you will need to make up the exhausts as they are bolt on type not sleaved as on the banshee.

2. You will need the complete wireing loom off the YPVS as the power valve is opporated by a 12volt motor, and magic box.

3. you will also need to fit a 12volt battery and charging system.

From my own experiennce I can assure you you are better off playing with your stock banshee engine in the long run to obtain more power.....

 

OK here we go again.

Your stock Banshee pipes will bolt straight on once you make up a simple exhaust spigot to bolt to the RZ studs.

You need to run the RZ wiring setup including the RZ regulator which is set up to charge the battery etc. Wiring consists of about 10 wires which can be setup as a stand alone loom and connects into the ignition switch and plugs into the Banshee coil, we will be producing a full wiring diagram, pretty simple........

Yeap when you use the RZ stator you also gain a 180 watt alternator, how much for a Ricky staor rewind again.......

Final word, any porting setup that makes HP in a Banshee will work BETTER in an RZ cylinder as you'll always get more midrange torque and a smoother transition onto the top end due to the powervalve setup.

 

Captshiner

Thanks for giving me all this information... But I've got a few more
questions.

Can you get replacement parts for the powervalve and the electrical stuff
required on the RZ?

Yes, I have asked that same question of the Yamaha NZ technical dept, whilst
body parts etc specific to the RZ may be difficult to get, The RZ was an
absolutely huge seller in the European markets and engine and electrical
parts are supposedly still in plentiful supply. The RZ 250 / 350 where
killed off due to the EPA in the USA market, heck they fitted them with cat
converters which knocked of 8 - 10 hp straight off...........

Electrical parts interchange between the 250 and the 350 RZ of the same
model year, although these will have a different part number, the stator,
YPVS, regulator etc are identical, The CDI unit have a different
manufacturers code but identical ignition curves (for the 86 models
anyways)and are fired by the same stator. So for electrical parts you are
not locked into just the 350 for parts supply.

Mechanical, the powervalves are pretty robust, the bushes can and do wearout
on high mileage road usage, these are pretty simple and a new bush can be
machined and inserted into the housing or you can just buy one from Yamaha.
The only other part is the connecting bush between the powervalves, if
allowed to come loose the ends of the valves get chewed out, on the flip
side I have seen high mileage engine that these have been in perfect
condition connections. If you take the time to set up the powervalves with
tight bushes, new seals etc I'm pretty sure you sell the quad before you're
worn them out.

Yamaha's world wide distribution means that they can get parts from Europe
or where ever. In NZ we often source parts from Yamaha Japan or Yamaha
Europe.



Does anyone know of any motorcycle salvage yards that specialize in RZ's or
is it just luck to find the pieces in decent shape?

Luck of the draw I'm afraid.

Am I limited to what pistons I can run in the RZ?

No. totally interchangeable with the Banshee.

or can I get those vito's 6 horse pistons?

Would work nicely in the RZ cylinders.

What carbs work best with it?

Stock RZ carbs where 26mm Mikuni, same as the Banshee but no TORS junk. You
don't have to fit big carbs to make the HP, a nice set of 28mm PWK's or
maybe 30mm TMX carbs would do the business, possibly the stock 26 could be
bored to 28mm.

would 34mm carbs throw off the powervalve?

Not sure what you mean here, the valves are electrically operated and start
to open at 5500rpm, full open at 6000rpm. Over carbing any engine just
loses low end and midrange for questionable top end gain.

I'm in the process of rebuilding my 92 Banshee, and after reading about
this, I'm seriously concidering doing it.

What mod do you have on your current engine ?

I'll post you an exploded top end daigram, wheel on down to your local Yam dealer and ask him on parts availability.

Kiwi - Craig