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Discussion Starter · #1 ·
Hi all,having had my Ktm exc 450 2004 for three months now I decided to check the valve clearances,put the bike in TDC (I hope)the valves were touching the adjusters but only just I then adjusted to 0.15mm,re assembled and started the e start would not turn the bike over so kicked it up felt like a lot more compression she ran fine but was tapping.worried I then repeated the process again the following morning noticing that the exhaust valves felt like there was more clearance reset and reassembled fired it up ran great until was hot then cut out and wouldn't tick over fire fine just won't idle when warm.left it to cool and then checked again but still no joy,any help please really struggling with this simple process??????????????
 

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Discussion Starter · #3 ·
Not 100% I have tried it both on the locking bolt and by rolling so the intake and exhausts lifters are free and checking the tolerance(rolling the exhaust down and checking intake and vice versa)
 

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KTM RFS Valve Clearances the Quick Way

Remove the seat and tank. Give the bike a good jetwash if it’s dirty.

Remove the horn and radiator guards. Remove the two bolts that hold on the radiators. Then remove the valve covers

Transmission in top gear, rear wheel off the ground, manual compression release held open with a cable tie at the lever on the head. With an 6mm allen key remove the bolt that is at the front right lower crankcase looking like it is screwing towards the crank (not the 8mm oil strainer that is in the bottom of the gearbox). Remove the thick washer from the bolt and put it safe.

Rotate the engine gently in the normal forward direction with a socket and knuckle bar (not ratchet) on the gearbox sprocket to locate the point where the inlet valve starts to close. Now look up the locking bolt hole with a torch, look for a machined groove in the crank. Turn the crank while looking for the groove, don’t go too far forward or back, half a turn max with the socket. Once you can definitely see the groove, don’t move the crank, screw the locking bolt fully home.

Cut the cable tie off the decomp!!!!!!!!!!!!!!

Adjust the inlet valves, valve clearance is 0.12mm which is 0.005 “ or 5 thou. But you don’t need a feeler gauge! Loosen the locknut and gently tighten the adjuster until you feel the slight resistance of it touching the valve. Now back it off 1/6th turn by lining up the nut with the slot in the adjuster then turn it back one flat. Then tighten the locknut without allowing the adjuster to turn. The locking nuts need to be tight.

Then tie the radiators back tightly with a rope to gain access to the exhaust adjusters. Don’t damage the fins of the radiator by bashing them against the head. I put a piece of cardboard against the left radiator where it presses against the water pump housing. Adjust the exhaust valves to 0.12mm as above.

Then replace the inspection covers and refit the radiators etc. Use blue loctite on the radiator bolts.

Note: with an auto clutch you need to drain the oil and remove the left engine case to turn the crank with a socket as the gearbox sprocket will freewheel.
 

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Discussion Starter · #6 ·
I feel pretty confident that I'm near enough but obv something's not right does it seem like the tolerances are to tight and when the engine warms up the valves elongate and don't go fully in the seat thus causing my problems???would this happen if I had adjusted on the decomp stroke?my piston was at the top of its travel when I locked it and checked clearances I think
 

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https://www.youtube.com/watch?v=hWS9RuEQzc8

Helped me, I taped my decomp in with bike up on stand and kept rotating my back wheel in a high gear watching the valve action......took a while before I was no longer confused but soon became clearer. REMEMBER to release decomp when finally checking the clearances! worth watching the vid over and over whilst farkling your back wheel round and round:)
 

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Discussion Starter · #8 ·
Hi guys thanks for the response,I have since again double checked over the valves,I let the intake valves open and piston go down,then slowly let the piston travel up controlling it in the front gear with a socket,the lines up the tdc grove with the locking bolt on the crank?both adjusters are free and set to 0.12,I am beginning to think the problem is something else,the bike starts great and I have since noticed if your on the revs it's fine ,as soon as you let it tick over once it's warm it cuts out or either when you go to rev briskly from idle it bogs and cuts out,any ideas please????
 

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Interesting, I just aquired an RFS 250 which ticks over lovely and runs nice on full gas. However is you crack the throttle it dies.

Kev this is a bike you are familiar with, I think you changed an engine casing on it. Any ideas before I pull the carb apart? I am thinking it the accelerator pump.
 

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Discussion Starter · #12 ·
Problem solved faulty ignition coil when warm was reading a high resistance than speced in the manual,so as a double check I borrowed one off a friend with the exact same bike and all is normal now! Thanks for the help
 
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