I havent said much about my Aprilia as I havnt been riding it, its developed a rattle, which I firmly belive is the power valves and I wanted to sort it out before it became a bigger problem. A full set of PV's from Suzuki \ Aprilia can be anywhere from $800 - $1200 and I wasnt keen to spend that sort of money fixing it. The issue with the powervalves is that they are 2 piece assembly joined by a pin, the pin can stretch and let go if not regulalry serviced which can cause a simple breakdown, right through to piston damage and engine failure etc. With that in mind I set off looking for an alternative, I found a guy on the UK who machines 1 piece billet power valves, I ordered a set and they arrived yesterday So what does a power valve do on a 2 stroke ? A power valve alters the port height at lower revs therefore giving more low and mid-range while still allowing the top end performance when they are fully open. Hopefully, I will get a chance to fit them on the weekend and see how she performs. I have added some pics of a standard PV and the new billet jobbies that I ordered. here is a blurb from the seller : RACING POWERVALVE REPLACEMENTS FOR RACE, TRACK, AND FAST ROAD BIKES. UNIQUE DESIGN REPLACES THE STANDARD POWERVALVES IN SUZUKI RGV250 VJ21 / VJ22 AND THE APRILIA RS250, GIVES MAXIMUM POWER AND ELIMINATES ENGINE DAMAGE DUE TO VALVE FAILURE FOREVER, GUARANTEED. JUST FIT AND FORGET, NO MORE INSPECTION STRIP DOWN'S NO MORE CABLE ADJUSTMENTS, NO MORE EXPENSIVE REPAIR BILLS, NO MORE WORRIES AND AN ECONOMICAL ALTERNATIVE TO ORIGINALS WHEN RE BUILDING A MOTOR OR REPLACING WORN VALVES. DESIGNED BY US, RACE PROVEN AND WERE FITTED TO OUR OWN BIKES, MACHINED FROM ONE PIECE ALLOY AND MADE IN SHEFFIELD ENGLAND NOT IN CHINA, CAN BE FITTED WITH BARREL AND HEADS IN PLACE NO GASKETS NEEDED UNIQUE DESIGN EFECTIVLELY SEALS THE EXHAUST PORT TO THE SHAPE IT WAS INTENDED TO BE FOR MAXIMUM POWER, LETTING THE EXHAUST GASSES ESCAPE FASTER, GIVING FASTER ACCELERATION OVER 7000 RPM DYNO PRINT OUT CLEARLY SHOWS THIS ON THE RESULTS FROM A COMPARISON TEST BETWEEN THE TWO TYPES OF UNITS NO MOVING PARTS CABLES OR LEVERS JUST FIT AND FORGET. COMES WITH EASY TO FOLLOW FITTING INSTRUCTIONS WITH ILLUSTRATIONS. STANDARD VALVES CAN NOT MATCH UP TO THESE VALVE REPLACEMENTS FOR, TOP END PERFORMANCE, SIMPLICITY, AND 100% GUARANTEED RELIABILITY, A FULL SET OF FOUR (4) RACE PROVEN UNITS FOR THE PRICE OF ONE NEW STANDARD SUZUKI POWERVALVE. "FOR MAXIMUM PERFORMANCE AND ZERO FAILURE" Here is a Video of a bike fitted with these PV's Mallory Park track day 26th June 2009 aprilia rs 250 part 1
il have pop round and take a look at this bike mate hope you had a good new year the vid brings back lots of memories for me riding round mallory park that track is fun to ride on a small to mid range cc bike :Thumbs_up:
Any news on these? Is there a printout of the dyno graph? Mmm, set and forget and never check you cables? Do these open and close?
Hard not to be sceptical. If they don't move the port won't be as big? Either the shape allows them to be closed all the time or open all the time. If closed top end will suffer, if open bottom end/ pickup will be affected? Hey I hope they work, power valves have been a pain in my arse since I bought my first rgv. I use red cougar pvs. They have the pin Cnc machined into the bottom blade. For a while(haven't seens these available for a few years) you could get just the middle blade with the pin machined into it.
Proper power valves are a good thing. I think you wasted your money. Should have just fitted the genuine parts.
As for"servicing" the pvs, its a matter of visually inspecting them. Yea, clean the carbon off them, but I've never seen a failure caused by carbon. That's myth no 1 busted. There are a few things to look for. Yea the roll pin that locates the blades to the bottom PC part. Don't go pulling it out n cleaning it n putting it back in. Just inspect it. Is it tight? Should be light interference fit. Has it vibrated enough to wear the hole, thus making it loose? If so replace either roll pin or complete pv. The other issue is the actual pv. It is operated by a hardened shaft that runs through the pv leg. It has a brass type bush on it. The hardened shaft wears the pv and the bush. This elongates the hole in the pv leg, allowing the pv to move deeper into the barrel, eventually tagging the piston. I have seen bronze bushes made to replace the brass type ones. The owner of that machine has had a few years of trouble free riding. But I'm sure he still inspects his pvs. Hope you guys don't mind the length of this
Hello do you have any contact details for the guy who made his power valve collars? I am looking for a drawing to make some from. I'm also going to machine a slight shoulder into the contact area to reduce pv wear. As for solid billet Non moving power valves. Yes they will eliminate a power valve failure. But if for road use will make the bike have no bottom end or mid range. Pretty useless for the road unless you ride everywhere at 10,000 rpm. Check out rs250 forum a guy on there Luca, sells New two piece power valves. No pins or slots but still move.
I'm not sure if he even had drawings. Just copied a standard one. They do have a chamfer on the pv edge
Hmmm that's a shame. I have my ones which are in good shape but I wanted the dimensions of a new one. I could end up manufacturing New worn collars if I copy mine. Is that chamfer supposed to be away from the valve and flat on the valve end?
I think I have a new one in the shed somewhere.I'll see if I can finds it and take some measurements and pictures
Care of Scotchy, I hope I've done this right! All measurements are millimetres Outside diameter Length Thickness Attempt at chamfer measurement Top of chamfer 4mm hole Position of hole from the bottom Position from the top
Ah nice. That's what I'm screaming about! Best I fire the lathe up and make some swarf. Thanks guys I will post a pic of mine and see how these Italian powervalves turn out.