rocker arm hitting spring retainer

I recently bought a 2003 450 sx in great condition ( so I thought), only to find out one rocker arm has been riding on the spring retainer on the intake side. The other rocker arm on the intake side has enough clearance so that it does not hit the spring retainer. Is it a common problem for the rocker arms to twist or is there something else for me to be looking for? I am already going to pull the head to see if the valve seat is worn and causing the valve stem to be higher than normal. I am also guessing the cam is probably going to be prematurely worn because of it. Since I will probably have to replace the cam, is there a cam that would be better for trail riding that I could replace it with?

If you do not fully understand the thread, please do not reply.

That's an odd problem. I can't say I've ever heard of a problem like this. To bend or twist a rocker arm, you'd think something else pretty catastrophic would've taken place. I remember one case of a rocker arm breaking off but that was a long time ago.

Let us know what you find.

Oh, BTW, your last sentence is probably going to cut down on any replies you get since it's pretty stand offish. I'm not sure I fully understand how the rocker is hitting the spring retainer but I'm afraid to ask for any more details because of that sentence.

Is it possible that the adjuster for that valve is all the way up (meaning a too high installed height on the valve) and is allowing the rocker arm to contact the valve retainer? That would be my guess second to something obviously being bent. Pull the valve cover and inspect the installed height on both valves, by the sound of it one is way out, like a sunken valve seat.

There were quite a few failures in the 2003 450sx related to valves. I suspect that it is the kickstart side intake that is touching?

My 450 sx the adjustment was almost all the way out on the kickstart side intake. It wasn't touching the rocker arm yet. I took the engine to Travis (trackside moto) for the six speed and told him I was concered about the valves. 3 minutes later heads off and it is obviuos that the valves are cupped, with the kickside intake being the worst. Now my bike has kibblewhite 1mm oversized valve with the kibblewhite spring kit. No worries.

It is easy to find Travis here or at KTMTalk (TravisD37).

When you get the head off I'm betting that your vavles have receeded, and will need to be replaced. This problem really only affected the 2003.

BTW my bike has the "55" cam not the "8/06".

Ah, I missed that it was an SX. Joe is right, there were some bad Ti valves in the 03's so it could very well be a badly sunken valve face.

I'm not convinced that it was the actual valves, valve springs, or cam that cause the failures (or a combination) but I was nervous that a valve would drop. No worries now.

My guess would be the valve is shot. My rocker had a groove in it from where it was hitting the retainer. Replace the valve with a stainless and a new spring and you'll be set. I also replaced the rocker for peace of mind.

The valve was getting close to dropping. The spring retainer is cracked in 2 places because of the rocker hitting it. I will be pulling the head off tonight. The motor had already dropped a valve with the previous owner. He said they had fixed everything under warranty. I am definately going to be doing some upgrading. Joe is right about it being the right side.

Thanks for the replys back.

Dave Hopkins, DJH on KTMTalk, did the head work on my bike. This is what he does

"I use the Kibblewhite valves 1mm oversize which allows my to cut a new face and still hold the valve up high, with stock size when you recut the seat the valve gets set lower which hurts the compresion ratio. I do a multi angle deal, the 45 degree seat blands into the chamber with a 30 degree and then a 17 degree, it also blends into the port with a 60 that is hand blended to the port. Ports and combustion chamber are glass beaded to remove carbon, I have teflon seals available but usually reuse the stock ones as they are not significantly worn." -from KTMtalk

i broke a retainer on an 03 525.

How much does it cost to have the head work done including the valves?


I think whats happened here is your retainer broke and that allows the valve keeper (tapered) to sink into the retainer. I wonder if you may have the 806 cam?? They are much more radicle then the workhorse -55 and as such are going to be a lot harder on parts. SX's have had I beleive 3 types of valve springs, as far as I am concerned someone there is in the dark ages on springs, all 3 are bogus while the EXC/MXC spings are excellent, I don't get it?

If you ship the cam with the head we can determine which cam you have, I recomend the -55.

Cost varies but assuming we need, normal valve grind, cut the seats for oversize valves + the valves, springs & retainer (ti) but avoid changing guides or seats would be the same package as Joe got it is under $350. If you run it thru Travis he will have gaskets, small parts, link etc and will rent you a chain swedging tool.

My recomendation is borrow a dremel tool grinder and nip the tips off one chain link so you can get the head off, then get Travis's tool as you reassemble.

Turn around is just a few days assuming we don't need seats or guides.

Well, I finally pulled the head off tonight and nothing is wrong with the head other than the retainer had broken causing the spring and retainer to sit higher than normal. The valve seats are not worn, so I would guess I lucked out.

Sounds like it. Glad to hear nothing bad happened when the keeper broke.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Similar Content

    • By Ponch
      I have a 2007 450 EXC that I recently installed a new clutch slave cylinder on. Per the 2007 KTM service manual it clearly states that the clutch needs to be filled with hydraulic oil, which I did (magura blood). That was yesterday. I went out to double check the level today and when I removed the cover, the rubber seal was all contorted and out of shape. I then looked at the cover and it's a Brembo clutch and says "DOT 4 brake fluid only".
      I flushed the line and the master cylinder about 7 times with DOT 4 brake fluid and there was no sign of the magura blood left in the system. My question is: other than the rubber boot on the master cylinder, what damage might have been done by putting in the hydraulic oil? It was in for about 24 hours.
      Thanks in advance for any advice!
    • By pumpernickelBrad
      Hi Folks!

      Sorry if there are a bunch of threads already but I used the site's search function and didn't find anything so far...

      I just found a decent deal on a '14 350 EXC-F with 11k km (unknown hours). Has a few goodies including skid plate, hand guards and it's for sale for about $2k CAD less than a '16 with 6k km on it.
      The bike is in showroom condition (appearance) with no indication it has been offroad at all.

      What would be the gotchas that would make this deal realistic? I'm coming from a WR250R where the engine lasts forever, is 11k street kms high for these bikes? 
      Are there any big defects in the '14s that I haven't dug up yet?
      With no service records what things should be done, checked, etc?
    • By Brannnt
      I purchased an '06 525 EXC some time ago, and recently pulled the motor out of the frame to address some other issues. When I removed the clutch slave cylinder, I noticed an issue the previous owner neglected to tell me about during the purchase.
      It appears that at some point, the chain broke and damaged the engine case near the clutch slave cylinder (see pics, please). I have noticed that the clutch does not fully disengage (bike lurches a bit going into gear, neutral is hard to find... its worse when engine is cold) ... I did not notice any leaks around this area (mineral oil or engine oil) before or during disassembly. 
      The previous owner (or someone) repaired it with some sort of epoxy.
      Without doing my due diligence (checking clutch fluid level, bleeding) I hesitate to state that this is the cause of my clutch disengagement issue ... but pardon my ignorance here and help me out: How bad is this?  Am I looking at replacing my engine case here or is the previous owner's jerry rig good enough?

    • By Black Sox
      Just bought a new 2017 350 excf ,will be doing 98% off road ,ordered skid plate bark busters ,
      my ? Is what's the best easiest way to eliminate rear fender light assembly.I still would like to have a break light.
      xcf fender will fit so dealer says,under $50.00 👍But xcf brake light $125.00 .👎What's the best economical way of doing this?
    • By JNV
      Hi friends from Spain.
      Mi new KTM