2011 350sxf 100 hours re-freshing the bike - Page 2 - KTM Forums: KTM Motorcycle Forum
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post #11 of 41 (permalink) Old 04-15-2016, 10:26 AM Thread Starter
Join Date: Oct 2015
Location: Toronto, Canada
Posts: 91
Also got a chance to help my friend with his 2015 500EXC.
SO much easier with the single cam and rockers design (like my old honda's were).

Just remove plug and valve cover and gasket.
Rotate rear tire for find TDC. This one has a bigger distinct punch mark on the cam holder and the cam gear. Line those up to get it TDC.

Measure clearances.
If having to replace shims it's much easier on this design.

Unbolt the rocker pin bolts. Remove the side cover "port" wholes to access the rocker shafts from the brake side of the head (make sure not to lose little rubber seals). Be mind full that the shaft have the ever so slightest "flat" across the top and that's the same way you should reinstall after you're done with the flatter side on top. To take out the rocker shafts use one of the M6 bolts and thread in the side of the rocker shaft from the side access port whole just enough so you can grab hold of it and slide it out.

Use a magnet to get the shims out of the buckets.
Re measure shim sizes and deduce the difference needed.
Replace with new sizes of shims using a magnet to locate the shim in the bucket and then gently use your fingers/finger nails to rock it into place.

Reinstall rocker shafts (flat side up) using the M6 bolt same way you took it out. Reinstall shaft pin bolts and the valve cover gasket and cover. Don't forget to reinstall the shaft access port hole covers/bolt on the side of the head with the little rubber O-rings.

Last edited by serialize; 12-14-2016 at 10:38 AM.
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post #12 of 41 (permalink) Old 04-15-2016, 10:55 AM
What the curtains?
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Join Date: Feb 2009
Location: San Diego
Posts: 12,951

I thought all the new 4 stroke KTMs were DOHC.

Thanks for pointing that out.

2012 Yamaha Super Tenere
2008 KTM 950 Super Enduro R

Past Rides
'14 Honda NC700X
'11 Husaberg TE 300
'08 Husqvarna 610 TE
'06 Ducati 1000S Multistrada DS
'04 BMW 1150 RT
'03 KTM 450 EXC
'02 KTM 640 LC4e
'01 Honda XR650R
'00 KTM 520 EXC
'98 Honda XR600R
'95 KTM 620 RXC
'90 KTM 500 MX
'88 Yamaha TT600
'86 Yamaha XT 350
'84 Yamaha IT465 (STOLEN)
'83 Kawasaki KDX 450
'83 Honda CB1000 Custom
'82 Kawasaki KDX 400
'77 Yamaha DT200
'70 Honda CT70

See you at Papa Fernandez!

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post #13 of 41 (permalink) Old 04-15-2016, 03:48 PM Thread Starter
Join Date: Oct 2015
Location: Toronto, Canada
Posts: 91
All back together and ready to rock!
Just waiting on some fresh rubber but will install that later when they come in.

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post #14 of 41 (permalink) Old 09-06-2016, 10:00 AM Thread Starter
Join Date: Oct 2015
Location: Toronto, Canada
Posts: 91
Well, though I'd post up some more since the last "big" maintenance.
Since then have done oil/oil-filter every 10 hours and air filter every ride.

Only changes since then were a neat little riser kit I installed (it was $34.00 and is universal so I can use on other bike. It's designed like shims so youcan change sizes to try different heights. Neat little in-expensive product:
BikeMaster Handlebar Risers Black 1 1/8"

Also installed Enduro Engineering Bark Busters with hand guards.
These go without saying top notch stuff.

Oh yeah and I installed heavy duty tire tubes and Micheline Starcross 5 Tires (100/19) in soft compound. Amazing tires!!!
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post #15 of 41 (permalink) Old 09-06-2016, 10:37 AM Thread Starter
Join Date: Oct 2015
Location: Toronto, Canada
Posts: 91
It was time or valve shims check again and probably replace this time due to some symptoms that have arose. Figured it would be exhaust shims and I was right. Bike has some difficulty on cold starts and also some backfiring when hot and well into the days ride.

So I tackled the job again.
Some important things to point out with the valve shim check is the bike must be TDC, and I searched this quite allot on the web and have seen some confirmation that for this KTM is doesn't matter whether comp or exhaust stroke for the TDC, just line up the dots to the flats behind the cam lobes (on the opposite side from the cam chain/gears). When you have those lined up you can use the locking bolt without the washer on it to lock the engine in place (see my earlier post in this thread for detail). If you are using the locking bolt it's recommended to disconnect battery to avoid any possibility of the starter button hit by accident. I also pull the throttle cables out of the way to help access the area better.

Once you are at TDC and you have measured the clearances (manual asks for 0.13mm-0.18mm on the exhaust and I had 0.13mm and 0.12mm and decided to change both) then mark the cam chain so that you know where to put it back and not mess up the timing. I use a wax pencil and mark both cam gears to the chain in 2 spots each, and also I zip-tie one of the cams (only remove and work on one side at a time). This was no possibility to mess up the timing.

Before removing the cam bridge, I found that the upper little rad hose in the frame was in my way (could be the aftermarket ones I have might be thicker) so I used a couple zip-ties to pull it towards the frame and little out of my way (just made life easier).

When removing the cam chain tensioner, note that there is barely any clearance from the frame and adjacent rad hoses. Use a 28mm hand wrench (I could not fit a socket). When you loosen the larger bolt (the little one is for adjustment you don't need to loosen that right now, that comes later), try and take off the large 28mm bolt/holder first and not bring the piston with it (both won't come out together doesn't fit or have room). When the bolt is off you can pull the piston out separately and make sure not to lose/leave behind the rubber O-ring for the piston.

Cam comes out, pull up the little black plastic shim covers (don't know the name they just sit on top of the shim and are what the cam lobes press.
Then swap your shims to the correct ones based on your clearance check and desired clearance. Reinstall the cam, line up your marks when putting on the chain, and then move on to installing the tensioner.

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post #16 of 41 (permalink) Old 09-06-2016, 10:41 AM Thread Starter
Join Date: Oct 2015
Location: Toronto, Canada
Posts: 91
Note, for the tensioner you have to set it to it's shortest (and locked) position to be able to install it otherwise it's open too far and will over-tighten and press really hard against the chain. It's simple to set, with the skinnier size down on a flat surface (table), I used 2 quarters (Canadian money not sure if US is same size) and press down HARD until it squirts out the remaining oil in it and locks down to that position with only 3mm or so of the piston showing. You can install like this. Then when you put back the piston with O-ring and then the 28mm bolt to hold it, you take off the smaller bolt to access the piston to give the "initial installed tension". Using a fairly skinny phillips or robby screwdriver press the part of the piston you can access from that bolt whole until you feel/hear it pop out to the default tension to hold your chain.

Now you can remove the locking bolt from the engine, and in top gear (sorry forgot to mention earlier but this is the same way you find TDC) you rotate the rear wheel to turn the crank a few times. Then find TDC again and lock the engine again. Now with your new shims you're re-checking the clearance to make sure the work you did is correct (I just like to make sure the crank was rotated a bunch of times before checking the reading again of the clearances).

Re-assemble the rest (valve cover gasket and valve cover) and get ready to rip and test out how the bike runs. I rode twice this weekend after the valve adjustment the bike starts instantly always, and not one backfire in about 12 hours of riding. Anyone have any questions on this stuff, I'm no expert but I'm happy to share any experience from doing it myself and other stuff I've read online.

One thing I did notice lately is I burn around 400 +/- ML of oil around every 8 hours of riding. Also on the magnetic oil drain plug had some small metal particles and one circular aluminum shaving (see pic). I have a feeling (and hope it's only this) that the oil ring on the piston is deteriorating. I plan to do the piston and rings this winter anyway and just hope it's not something else and lets go before then (still have lots of fall riding to do lol).

I've been riding with a broken foot for the last 5 weeks and just getting little better now and really enjoying the weather cooling off slightly too (was an absolute scorcher of a summer up here). Cheers and happy riding!!
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post #17 of 41 (permalink) Old 12-12-2016, 10:26 AM Thread Starter
Join Date: Oct 2015
Location: Toronto, Canada
Posts: 91
So, prior to posting the big long details on the top end rebuild I just started, thought I'd just throw up a note about gearing.
Was running the stock 14 front and a bigger 52 rear, and never quite had the right pull in the tight single track for 2nd and 3rd. Switched to a 13t front and 51 rear and it is perfect!! This is the offroad gearing if you have a 350 SX.
Also safety wired my sprocket, from years racing and seeing parts fall off occasionally I just had to get the piece of mind.


Will be posting the top-end rebuild first half soon (the tear down).
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post #18 of 41 (permalink) Old 12-14-2016, 09:04 AM Thread Starter
Join Date: Oct 2015
Location: Toronto, Canada
Posts: 91

So here goes the tear down info.
Also can't seem to get my photobucket photos to work and using google which
seems to share the link only and not the image itself.

First off, clean the bike very well. All the wiring harness and those components above the head can drop all kinds of dirt into the head and eventually bottom end when you have it all apart.

Start the process off same way as if checking valve clearances.
Pull spark plug wire.
Pull valve cover bolts.
Remove engine brace brackets.
Remove valve cover and gasket.
I zip tied my throttle cables to the frame and out of the way.
I removed the upper rad hose so that it gives clearance to remove the head.

Next, we have to find TDC.
I use the rear wheel and put the bike in top gear 5th on the SX.
Rotate until the dots on the cams opposite end (not the gear side) line up with the flats of the cam gear.



Once these are lined up there is a bolt on the bottom of the bike to lock the crank at TDC (and this also confirms you are in fact at TDC).
Drain the motor oil from the bike and then pull the crank-locking bolt, remove the thick copper washer and reinstall so it goes fully in and locks TDC.


Next, I take an extra step to mark my timing and I don't believe it is necessary but for me it's an extra piece of mind. Using my wax pencil I mark a point on the cam and also that link in the chain where it sits on the cam gear. And I do this on both cams. This way once the chain is off and I go to put it all back together later I can use this to confirm my timing is same as it was.

Last edited by serialize; 12-14-2016 at 09:47 AM.
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post #19 of 41 (permalink) Old 12-14-2016, 09:45 AM Thread Starter
Join Date: Oct 2015
Location: Toronto, Canada
Posts: 91
Before removing the cams or head, the air intake needs to come off.
In an online how-to video I saw a guy unbolt the rear subframe and lift it just enough to pull off the intake boot. The exhaust will need to be removed to do this. (good video).

Next, will have to remove the cam chain tensioner to be able to remove cams and the entire head. When pulling the tensioner pull the big bolt (24mm) and remove that first before pulling the actual tensioner and rubber o-ring (hard to get it to clear frame and rad hoses otherwise).

After tensioner is out the cams can be pulled.
Remove the aluminum shaft for the spark plug port.
Remove the cam bridge (working the bolts from out-to-in as per manual).
Remove the cam chain off the cams and I made a zip tie loop and hooked it on the frame so doesn't fall into the bottom end.
Remove cams to be able to access the bolts to un-bolt the head.


The bolts to remove the head are 50Nm so they will be a little tough to get off. 2 on the outside of the head and 2 inside the head just under where the cams sat. Also there is one bolt that holds the head to the cylinder specifically (the long ones actually pass though both head and cylinder to hold on the block), and this little nut needs to be taken off on the cam gear side outside of the head.
You have to give a tug and free up the head gasket and carefully lift and slide the head off the cylinder. Note to pull it out of the frame, due to clearance issues on the SX model you have to lift as high as you can, and then rotate it to get the wide side out of the frame and can tip and pull it out.


Last edited by serialize; 12-14-2016 at 09:54 AM.
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post #20 of 41 (permalink) Old 12-14-2016, 10:07 AM Thread Starter
Join Date: Oct 2015
Location: Toronto, Canada
Posts: 91
Next, the cylinder needs to come off.
It is actually free at this point just firmly in place from the piston and base gasket holding it. You have to firmly but gently pull it up off the piston and remove from the bike.


I kept the gaskets in as best condition as I could. Even though getting new ones just keep for piece of mind in case absolutely in a bind and need to reuse them (which is not recommended).
Also when it comes to the old gasket material left on the cylinder (mine had the top half of the base gasket caked onto the bottom of the cylinder) be very careful when removing the old material so you don't comprimise the sealing surface. I used carb cleaner and a PLASTIC putty knife (painting tool) very lightly losening up the gasket material with the carb cleaner and most of it came off with my finger nails leaving the surface underneath perfect.

I was checking the head for marks and wear by running my fingernail on the front and back (exhaust and intake sides) where the piston skirt runs. It doesn't feel too bad, you can visibly see some wear on those parts but could be normal. I am taking the cylinder to a professional engine builder to get looked at for wear and measure for roundness and bore. This will tell me if needs to be milled to a new size piston, or if needs re-plating, of if it's fine and just get the sizing to know what piston to get (A or B). KTM SX model uses a very good Vertex high compression piston.


The head will also be dropped off at the engine builder. I am not an engine specialist of even close to knowing what wear to look for and changing valves, guides, seals, re-cut, change springs etc. So will leave that to the pro's and get cylinder and head cleaned up all at once.


Last edited by serialize; 01-23-2017 at 05:24 PM.
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