Adjusting valves on 400 MXC... TDC?

[E-Ticket]

Until I can locate an dang engine manual for my KTM 400 MXC....

--what is the hot setup for determing TDC?
-- and is it on the compression stroke? (should be....)

Valve clearances:
Intake: ??
Exhaust: ??

How many riding hours until 1st and second adjust?
-- and then how many hours between after that?

I know, I know... so many questions... (grin)

 

[Strick]

Here is a little blurb I stole from AFM744 at Holeshot ( I hope he doesn't mind ): it's VERY important to correctly use the crank lock bolt to avoid the auto-decompression from throwing off your settings. Be sure you're on TDC between compression and power stroke. Pull magneto cover, line up the trailing edge of the magneto firing block with the top edge of pickup, THEN pull lock bolt and reinsert sans-washer by hand. Soda straws and zipties don't belong in your spark plug hole. You should feel the bolt center in the notch in the crank, and it should NOT turn at all in either direction. I've seen lots of posts where people just screw this in and then turn the crank til it stops, this is bad.
Again, second time you do the valves you won't be learning it. No, there's
simply no way to do it the right way w/o changing the oil

My explanation is different, but achieves the same result.

Intake: .004, exhaust .006

I went 500 miles my first setting, and since I have another 500 on my bike now and have to change the water pump seals anyway, it is time again. You can easily tell when it is ready. The bike gets hard to start.

Here is my start to finish: Start with a clean bike
Remove seat/tank
Remove radiators
Clean everything in and around open frame.
Blow compressed air into the plug clearing port on rt side of engine after pulling the plug cap off.
I use a LONG soda straw in the cylinder to fully determine TDC.
You need to remove your skid plate if you have one.
There is a large allen head bolt on the lower rt hand side of the motor.
This the crankshaft locking bolt that is supposed to lock the crank at TDC.
Take out the bolt, remove the copper washer. screw the bolt back in, but not all the way in --> IMPORTANT!!
Put the bike in 6th gear, and use the rear tire to rotate the crank/piston. Once you think you have found TDC by the straw and/or the flywheel marks (I did not remove my side cover to adjust my valves (find TDC), I might next time).Remember intake, compression, power, exhaust. TDC is at the top of the compression stroke.
To find TDC the intake valves should open (springs will be compressed) then slightly after that is TDC. When you get to the point where the intake valves open and then begin to close, tighten the crank bolt in by hand to not tighten any more than that.
Rock the engine a little bit back and forth LIGHTLY and you should feel the crank bolt engage, so to speak.
If you decide to remove the side cover, verify the flywheel to the timing mark.
The feeler gauge goes under the knob looking thing that sits on top of the valve stem. Once again intake .004, exhaust.006.

You will either need to buy the angled gauges or bend your existing ones to a 45 degree angle. Remember when tightening for clearance you should feel a definite drag on the gauge.

Reverse sequence to pin 'er back up.

 

[E-Ticket]

woof! thanks for the detail, Strick!

Do you have to drain/pull radiators? Or just unbolt and pull out of the way?

I'll only have about an hour or two or riding time on engine before we do the Reno_Moon Rock ride. (damn rain..!) I'll still be at break-in pace and won't be thrashing the engine. So I'll probably wait until after Reno to adjust teh valves. I'm alway *real* slow and careful the first time I do anything major.

Looking forward to meeting you and riding with you! Cheers!

-- RandyB

 

[ktmwes]

Originally posted by Strick
Here is a little blurb I stole from AFM744 at Holeshot ( I hope he doesn't mind ): it's VERY important to correctly use the crank lock bolt to avoid the auto-decompression from throwing off your settings. Be sure you're on TDC between compression and power stroke. Pull magneto cover, line up the trailing edge of the magneto firing block with the top edge of pickup, THEN pull lock bolt and reinsert sans-washer by hand.

Excellent procedure Strick, I wish they would just put that in the owners manual (they put everything else in it) Just a thought and I came up with this on one of the boards that was very helpful to me, was after locating the mag timing notch with the crank sensor, with a flashlight look into the lockbolt hole while slowly turning the mag with a wrench and you can center the notch perfectly in the middle of the hole, then just run the lock bolt in the hole and your ready to adjust valves. It gave me alot of confidence when I tore down my top end with out a manual.

Wes

 

[dstktmusa]

Hey guy's

check with your dealer regarding the valve clearence for the RFS' I just received a tech bulletin from KTM that states that the clearence was misprinted in some repair/owners manuals. The correct clearence should be 0.12mm for both intake and exhaust. The tech bulletin number is 0230.

 

[Strick]

To interpret: .12mm ~ .005 in. Don't get confused here.

I too have a couple of copied pages from an rfs manual that states .005 intake and exhaust.

I have not been using that spec. and all is well.

This does mean you can by the angled feeler gauge from Sears, that only goes as low as .005 in. and you are good to go.

Hey DS, why doesn't KTM send the bulletins to titled owners? It sure would be nice, especially when it goes against their own manuals.

 

[jeb]

Good question, Strick. I used to get the KTM Underground sent to my house but not anymore. I'd like to get back on that mailing list, too.

 

[TexKDX]

Has anyone calculated the clearance based on the thread pitch of the adjuster? A KTM dealer that went thru an early KTM RFS service training class in '99 told be that they were told to tighten the adjuster until it makes contact, then back up 1/4 turn and tightent the lock nut.

dstktmusa and others, any comment on this method?

 

[Strick]

My local dealer uses this method Tex. With measurement, and practice, I probably will too.

 

[Rodzilla]

Can anyone post pictures of the process?

I getting ready to do the first adjust on my ride and being a "visual" person the pix sure help.

Can't be to much more to it than on my XR but I like to go in prepared.

Rod:confused: