Superpacman13

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We have produced a set of titanium valve retainers for RC390's, you may ask why we would do such a thing? We have found that with extended high RPM usage the stock valve retainers will fail. The angles between the collets and the retainers do not match well enough for them to hold they valve clearance for very long, typically resulting in zero clearance. This becomes an expensive issue to replace the finger followers and cams on a frequent basis. An additional benefit is increased valve control due to the slightly reduced retainer weight, we also increase the preload on the spring to bump the seat pressure. These retainers also use the much more commercially available 9.48mm valve shim which is much easier to find then the KTM 9.5.
KTM RC 390 Titanium Valve Spring Retainers
Pictures of the damage.
IMG_20160413_184008148.jpgIMG_20160413_184055860.jpg
 
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Tom

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So if I want to reliably rev to the redline 11k redline with your intake box, all I need is a set of your retainers? Is there any down side to having increased spring pressure on the stock springs? Increased cam wear?
Out of curiosity, how high are you able to rev with your SBK 390? Can you post a sound clip on youtube? I wanna hear what this motor sounds like when it screams =D

Would a SBK build be reliable as a street only bike? I have no intentions of racing, but I love how light this bike is, and dont want to move up in weight to a 600. Mostly the bike is used to occasionally commuting to work, or riding with some frinds. All of them have 600s =/
 

Superpacman13

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So if I want to reliably rev to the redline 11k redline with your intake box, all I need is a set of your retainers? Is there any down side to having increased spring pressure on the stock springs? Increased cam wear?
Out of curiosity, how high are you able to rev with your SBK 390? Can you post a sound clip on youtube? I wanna hear what this motor sounds like when it screams =D

Would a SBK build be reliable as a street only bike? I have no intentions of racing, but I love how light this bike is, and dont want to move up in weight to a 600. Mostly the bike is used to occasionally commuting to work, or riding with some frinds. All of them have 600s =/
You don't need anything technically to reliably rev to 11k, no downsides that I have found in a year and a half. The SBK doesn't rev any higher, it doesn't need to. The reliable limit of the RC's seems to be right around 50hp. Get there how you wish.
 

Tom

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How do the titanium retainers affect the service intervals for having the valve clearances checked? I'm having a set installed during my 650 mile service, and just realized I have no idea when I would need to have them checked again after the install.
 

Formula390

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PacMan would say for certain, but most likely I suspect he would say the service intervals for CHECKING would not be changed. What would likely change is how frequently the clearances would need to have the shims changed.
 

Superpacman13

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How do the titanium retainers affect the service intervals for having the valve clearances checked? I'm having a set installed during my 650 mile service, and just realized I have no idea when I would need to have them checked again after the install.
You only installed reliability. Normal service interval and it more then likely won't need adjusted until the valves fail.
 

Tom

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Just got the bike back from the 600 mile service at the dealer.
$527.29 for the service (including parts/labor)
$330 for installing the titanium retainers

I would highly recommend this mod to anyone. After feeling what the factory steel retainers weigh compared to the titanium in my hand, I'm amazed. It felt like the 4 titanium retainers had the same weight as just one of the steel retainers. Also, the steel retainers look like something you would pull out of a lawnmower. They look like crappy pot metal, with a bunch of sharpie marks on the top, left over from the quality control after manufacture. The titanium parts look slick as snot, and they just have an aura of being high-tech. Even the mechanics were asking where these were from, they though I had them custom made. If Gray Area KTM didn't ship these in nondescript cardboard, they could easily sell these for way more in a fancy box.
 
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