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12/27/2016
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Glogow, PL
Valves in my KX250 2019 went south after 120h, price for OEM replacement is kinda crazy so I was thinking about aftermarket ones. ProX Titanium Valves are probably the only alternative, any opionions about them? Also I'm not interested in SS ones. Thanks.
Everything ProX makes is OEM quality or better. I can personally vouch for their valves, we use them in the race bikes after the stock ones time out.
ProX is good stuff
After shopping for pistons on RMATV and seeing Proxs piston they offer for ktms is cast without a skirt coating and the OEM piston and every other aftermarket piston is forged with a skirt coating, I'd never run anything they use. The OEM quality or greater stated above is untrue. Also I put a prox clutch in a Yamaha and it said made in China on the box.
The prox photos on RMATV are not accurate, most prox modern 4 stroke pistons are forged and do have skirt coatings. Their 2 stroke pistons are cast, just like all oem 2 stroke pistons, and they have started to add skirt coating to most newer model 2 stroke replacement pistons as well.
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I used to work for a company under the same parent company as ProX.
ProX has great quality products. They are very good at finding the OEM manufacturer for said product and having it private labeled with minimal changes.
The Ti valves are likely the OEM manufacture with a different radius on the back side of the valve or something small like that.
A lot of their stuff is now made in China or Taiwan since the company was bought by the Race Winning Brands conglomerate. They are not necessarily the quality that they use to be. If its a new product, like valves or complete crankshafts, I would be cautious about the quality.
All 6 or more of their pistons I've purchased for my yz125 have had the skirt coating and said made in Japan on the packaging (including the piston ring which comes from a different Japanese mfr.).
This used to be true, but it’s not anymore. Once they were acquired by Race Winning Brands, they started sourcing parts based on price and not quality.
Their 4 stroke pistons have no coatings, nor do the wrist pins. Their 2 stroke piston design is awful and cheap. At 10hrs it looked worse than my stock 100hr piston. I just bought a steering head bearing set thinking they must still be made in Japan… Nope. Made in India stamped on the bearings
You’ll still find some good Japanese parts in their catalog, but with them constantly seeking the cheapest suppliers it’s a crapshoot and the odds keep getting worse. Never know what you’ll get.
Pistons no, valves yes
120 hrs on OEM ! why to risk it for $150 savings and possibly problems? OEM , no brainer.
My 19 kx450 intake valves were worn at 80hrs. I replaced all the valves with ProX. Mine said made in Russia I believe. I used them in my 08 crf450r. I’d get about 30hrs out of oem and I would get 70 out of the prox. The bike had a couple hundred hours on it and original seats. So the Pro X valves are definitely quality. I never changed the springs on the Crf450 just valve seals when replacing valves. I replaced everything on the kawi with oem just used the ProX ti valves. Weight was the same. Coating looked lighter than the kawi oem valve.
Check with Del West and Xceldyne for valves. Those two companies supply F1, Nascar and all the high end series, and are often the source for other makers private label valves.
Not to get too pointy headed about it but do ask whatever seller you go with if their exhaust valves are made from the Titanium 6242 alloy. This is the high temperature grade that doesn't fail. The Inlet can be the same material as the exhaust or the slightly cheaper 6-4 grade.
Do make sure that they are coated with chromium nitride - CrN. My .02 cents
Well in the description for a KTM 350 4 stroke it states that it is a cast piston several times and not once is the word forged found in the description . Went to pro xs website, under piston kits forged isn't mentioned once aswell
I just rebuilt an older KX125 for a friend and the crank bearings and seals matched the OEM perfect with both brand name and numbers exactly the same. I hope they don't cheap out for more profit because it will bite them if they do.
They have already cheaped out for more profit. Done deal. Some of the older part numbers like from that KX125 are still good simply because they haven’t gone back and found a cheaper source yet. They will get around to it eventually. All their newer part numbers (for the newer bikes) are hot garbage.
I hate to hear this. I usually use OEM, but often used Pro-X because it was good stuff.
In the past, you were getting the OEM stuff just in the actual manufacturers packaging. Pistons were stamped ART and were the exact same piston as OEM. My last piston from them had PROX cast into it not ART. They were visually different in a number of ways including weight. It is a real bummer when these companies sell and get run by guys who essentially destroy the brand. PROX went from a no brainer to a crap shoot at best.
Race Winning Brands is well on their way to destroying ProX. There’s literally no reason to buy ProX parts if they’re the same cheap crap everyone else is selling.
Also, do you guys remember Falicon rods? Race Winning Brands bought them thinking they were buying crankshaft manufacturing capabilities. While Falicon did build rods, they only REbuilt cranks.
Upon learning this, Race Winning Brands fired everyone and shut down the company.
Screw Race Winning Brands. Buy OEM instead.
Pit Row
Anyone have any pictures of the latest products? I have only bought the ti intake valves from RMATV and that was a few years prior and latest was last year. Products were same quality as my first purchase. I did by some rear sprockets recently and they were good quality. Looked like the oem ktn sprocket. Did the product quality change recently- like last couple months?
Hard to imagine a company could spend that sort of money without knowing exactly what they were getting - not exactly a recipe for success.
One would think those responsible for the acquisition would be among the first to be unemployed.
Well.. here we go... ProX valve in my kx250 hit a piston. I could hear it was making more and more noise then next thing i remember was sound of something cracking inside the engine. Took it all apart. I suppouse valve bent a little bit wich caused guide to crack and that cracked part ended up under the other valve. That is pretty much all the damage i can see.
120 hours is pretty crappy actually, I've run titanium valves for 300+ without having to shim them.
Do the Kawasakis have shim buckets? If so that wear is odd. If no buckets and a rocker makes contact with the stem then the pro-x coating isn't hard enough. Anyway, this is why I run OEM, most of the time they're superior to any of the aftermarket options. If you want something better than OEM, it'll probably cost more not less.
Can lead a horse to water...
Lol. Why people post stuff and then they don’t listen to the advice?
120 hours is about 12x longer than what ol boy got now 🤭
Kibblewhite titanium valves, or del west are very hard to beat, one piece is ideal, don’t skimp on valves
What year bike?
It's possible instability caused that. YouTube "valve spring high speed video".
I tried some ProX Ti valves in my 2005 kx250f that I use for Michigan woods/trail duty. We hit sand regularly, and being 210lbs, I have to hold the throttle pinned and rev the piss out of it. (Poor bike). They've held up to 3 200+ mile trips so far. Prob about 30+ hours. No issues so far.
But...I also upgraded the springs and retainers to the latest (tappet style) versions. 2009+ (light weight sintered aluminum retainers, heavier progressive wound springs). I may have also used a thin spring shim, I'll have to check notes. The previous owner had installed heavy kibblewhite stainless valves with matching spring/retainer kit, and it all looked like garbage. Beat up and worn razor thin.
Del west, Xceldyne, ONLY!
There it is. From someone that has to fix all sorts of broken & worn out shit on a daily basis.
Austin, hope you are happy and staying stoked.
Happy New Year to you and yours.
Let's catch up at a race and go out for a beer and a steak...maybe even a really good burrito...?
Manny
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