KTM EXC 밸브간극조절의 꽁수

[드빌러]

언더가드도 떼지 않고,
점화플러그도 뽑지 않고,
크랭크스톱볼트도 풀지 않고,
마그네트카바도 열지 않고,
압축상사점을 찾느라 고민할 필요없이 밸브간극을 조절하는 꽁수가 있습니다.

또 필러게이지가 없는 사람도 간극조절을 할 수 있습니다.

어치피 캠-로커암-밸브로 전달되는 기계적 연결에서의 유격(간극)을 조절하는 것이므로
배기밸브가 이 기계적 연결에서 힘이 작동되지 않을 때 배기밸브간극을 조절하고,
흡기밸브로 힘이 작동되지 않을 때 흡기밸브의 간극을 조절해 주는 요령입니다.

압축상사점을 이용하는 것은 흡기와 배기밸브에 동시에 힘이 작동되지 않는 타이밍을 찾은 것이고요~

꽁수는 흡기쪽 따로, 배기쪽 따로 조절하는 대신에 압축상사점을 찾을 이유가 없으므로 지저분한 일들이 줄어듭니다.

기본적으로 시트, 바이크의 뒷바퀴를 뜨게 해 놓고, 기어는 5~6단을 놓고 연료통, 라디에터는 내립니다.
배기밸브뚜껑과 흡기밸브뚜껑을 엽니다.

조수에게 뒷바퀴를 진행방향으로 돌리라하면 엔진압때문에 힘들어 할 겁니다.
---> 감압밸브를 잡아주고 돌리라고 하세요.

[흡기밸브간극조절]
몇바퀴 바퀴를 돌리게 해서 배기밸브의 움직임를 관찰합니다.
이제 움직이는 폭을 대략 짐작할 수 있으면 천천히 돌리라 하고 배기밸브가 열리기 시작할 때를 찾아냅니다.
그리고 더 천천히 돌리게해서 배기밸브가 반쯤 열릴 때 바퀴를 멈추게 합니다.
아마 이때가 밸브스프링의 힘 때문에 조수가 어려워할 때인데 그 자리에 바퀴가 고정되게 밧줄을 스윙암, 브레이크 페달 같은데에 역던지, 장대를 바퀴살에 집어 넣어 스윙암에 고정되게 하던지 하십시요.
이렇게 배기밸브가 반쯤 열리는 도중일 때는 흡기밸브로 힘이 전달되지 않는 타이밍이므로 흡기밸브의 간극을 조절하시면 되겠습니다.

[배기밸브간극조절]
같은 요령으로 배기밸브로 힘이 전달되지 않는 시기를 찾아 조절하면 되는데, 그 타이밍은 흡기밸브가 다 열렸다가 반정도 닫혔을 때입니다.
다시 조수에게 뒷바퀴를 돌리게 하고는 흡기밸브를 관찰하다가 다 열렸다가 반쯤 닫힌 타이밍에 바퀴를 멈추게 하고는 밧줄, 막대기로 바퀴를 고정시키고 배기밸브의 간극을 조절합니다.

[요약]
흡기밸브간극조절타이밍=배기밸브가 닫힌상태에서 반쯤 열리는 중.
배기밸브간극조절타이밍=흡기밸브가 열린상태에서 반쯤 닫혀갈 때.
엔진이 차가울 때 흡, 배기밸브간극은 모두 0.12mm

[1/6바퀴 돌리기테크닉]
원필자는 이 방법이 좀 부정확한 방법이 아닌가, 재는 것이 정확한 것 아닌가 의심하면서 처음에 몇 번 작업을 했지만,
지금은 아예 필러게이지로 재지 않고 이 방법을 사용한다고 합니다.
실제 필러게이지를 작은 틈새에 넣고, 재고하는 것이 쉽지 않은 작업입니다.  

KTM 간극조절볼트가 한바퀴 돌면 0.75mm진행하게 만들어져 있는 점을 이용합니다.
고로 1/6바퀴만 돌린다면 0.75mm/6=0.125mm가 이동되게 됩니다.
대게의 다른회사바이크도 볼트의 나사산이 같지만 후사베르크는 볼트의 피치가 달라 1/5바퀴만 돌려야 하는 것으로 알고 있답니다.

방법을 소개드립니다.
볼트고정너트를 충분히 풀어주고, 조절볼트를 반바퀴쯤 풀어준 다음에 조절볼트를 돌려 볼트와 밸브쪽이 닿는 때를 찾습니다.
볼트를 조금씩 멈춰가면서 돌리는 것보다, 한번에 연속적으로 돌려야 찾기 쉽답니다.
닿는 점(간극=0mm)을 찾았다면 그 볼트에 딸린 고정너트를 조금 돌려 대각선이 날로 조절볼트의 드라이버날 선과 일치하도록 맞춰봅니다.

이 너트가 6각이므로 1/6바퀴를 풀어야 한다면 너트의 어느 각도인지 쉽게 알 수 있습니다.
반시계방향으로 바로 옆에 위치한 너트의 각진 부분이죠.

현재의 각도보다 1/6바퀴 풀어주어야 할 각도에 표시를 해 놓던지해서 최종적으로 조절볼트가 위치해야 할 각도를 확실히 해 둡니다.

그 표시만큼 1/6만큼 조절볼트를 푼 다음 그 위치가 유지되게 고정너트를 조여야겠죠.
고정너트 조일 때 조절볼트가 따라 돌아가지 않게 잘~

[필러게이지를 사용할 때]
충분히 푼 다음에 0.005인치짜리 필러게이지를 넣고, 뽑지 않은 상태에서 조절볼트를 맞추고 고정너트를 조이는 방법인데,
실제 해 보면 필러게이지가 약간 손상되기는 할테지만, 뽑고하는 것보다 뽑지 않고 하는 것이 훨씬 편합니다.

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Valve adjustment
KTM RFS (or ANY 4 cycle) engine

Top Dead Center: Commonly referred to, as TDC is the point where the piston
is up.

Power stroke: On a 4 cycle the engine produces power every other time the
piston is up, while the piston and crank are in the same position (TDC)
every turn the cam turns of crank speed so the cam is in its position to
adjust, both cam lobes facing down every other turn! Thus you cannot just
put the piston at TDC and adjust, the odds are 50/50 that the cam is in the
right spot.
Overlap stroke: The other turn where the piston reaches TDC is called the
overlap stoke, the valves are each open very slightly, approximately 1mm
with the exhaust closing and the intake opening. Not the place to adjust the
valves!

Clearance: To allow the valve to fully seat and transfer the heat it
accumulated when open, and to allow for heat expansion when hot, the
camshafts lifting pattern and valve train are designed to operate with
clearance lash or gap between the valve train and the valve. Too much
clearance and the cam and cam followers are prone to wear out. Too little
clearance and it can burn a valve, or if you are luck, just not start at all
so get it right. KTM has a service bulletin recommending that we ignore the
prior specs and set the valves at .12mm which in inches translates pretty
closely to .005.

Rotation: Note that the engine rotates the same direction as the wheels and
that when we rotate the engine we are fighting the valve springs, the
easiest way is to put the transmission in top gear, this gives the wheel max
leverage against the engine, conversely to how 1st gear gives the engine max
leverage against the wheel. Then we rotate the engine by the rear tire. If
you want to avoid pulling the spark plug out you can, just hold the manual
compression release while turning the engine.

Getting to it: First remove the seat & tank, from there I have done it
radiators on, and hated every minute of it, I have done radiators off, it is
more labor but maybe less maddening? (On '03 try setting the radiators aside
without disconnecting the hoses) Unless the bike is spotless I like to take
a can of Brake Clean and someone elses toothbrush, spray & scrub the valve
covers and the area around it, then spray the area around the spark plug
with the brake clean to flush out that area. If you have compressed air a
good blast would help clean debris out of this area but watch you eyes!
Then remove the valve covers and if you are going to the spark plug but if
you do it my way there is no need on the plug.
Now we must locate the heal of the cam where the valve lash is to be
adjusted.

Common way: The common way it to find TDC on the Firing stroke. The
problem with this is too many folks end up on the Overlap stroke. This
causes endless confusion, people putting straws down plug holes and endless
other tricks that still often leave them on the wrong TDC.

My way: With this method you do not need to remove the spark plug, magneto
cover, skid plate or the TDC bolt in the bottom of the crankcase or the
associated dirt.

Intake valves; Transmission in top gear, rear wheel off the ground, if you
have a helper one can watch the valves and hold the manual compression
release while the other rotates the engine with the rear wheel. Rotate the
engine gently with the wheel to locate the point where the exhaust valve
starts to open then rotate very gently until the exhaust valves are 1/2 way
open! Minor frustration, we are now fighting against the valve spring which
wants to roll the engine back, so to stop it you either have to have a
helper hold the rear brake or, as this gets pretty boring so;
Option 1; Take a tie down, hook one end to the brake pedal, wrap in under
the bike and up the left side to something like the top of the frame behind
the engine. Now just tighten the strap so the brake can keep the engine from
rolling back.
Option 2; Put a bar thru the spoke of the rear wheel adjacent to the swing
arm to stop the wheel.
At this point the Intakes are on Center of the Heal of the Cam. Proceed to
adjust.

Exhaust valves; As above, except, locate the point where the intake valves
have opened and are 1/2 way closed (engine rotating forward). As the intake
is closing the engine will want roll forward PAST the way point and the
lash in the transmission and chain will make it so you can not stop the
engine, so let it go just past, then roll the wheel backwards and secure it
with the brake or bar again. Now proceed to adjust the Exhausts.

ALWAYS! ALL 4 STROKE ENGINES: With the engine rotating its correct direction
the exhaust is adjusted when the intake is closing and the intake is
adjusted when the exhaust is opening!

Adjustment:
If you are a feeler gauge kinda guy; As the clearance is so small and you
can not get a straight approach with the feeler gauge dont be surprised if
you can not get it in. I like to loosen the jam nut (10mm box wrench) and
loosen the (one at a time) adjuster a couple of turns, slip the gauge in,
turn the adjuster down lightly against it, then tighten the jamb nut. In
doing so often the adjuster will creep tighter slightly and cause the
clearance to close up. What you need to do as you tighten the jamb nut is do
kind of an isometric exercise where you are holding the adjuster against
rotation with equal and opposite force of the rotation of the jamb nut!
This may take several practice attempts. As soon as you have tightened the
jamb nut, do not pull the feeler gauge out, just try to slide it around in
the gap! When you have it right it should slide with some, but minimal drag
or resistance, no drag and it is too loose, heavy drag and it is too tight,
may even be holding the valve open? Take a little time, you will have to
redo a few times at first but once you pull the gauge out you may not be
able to get it back in so get it right first! Oh, and by the way, the jamb
nuts need to be tight!

If you are a 1/6th turn kinda guy; I think it was the Husaberg guys that
came up with the theory that fraction of a turn will do! The Bergs have a
different thread pitch, I think they use 1/5th of a turn? My first reaction
was that is crude, then I tried it a few times, now do it every time. That
is based on a turn equates to .75mm (on the KTM tread) and.75 div by 6 =
.125mm and .12mm is spec so for all practical purposes 1/6 turn is right on!
Loosen the jam nut (10mm box wrench) and very lightly tighten (one at a
time) the adjuster till it contacts the valve, note where the screw slot is
aimed, turn the jamb nut to a corner of the hex aliens with the slot, make a
small scratch in the cover gasket surface in line with the next hex point
left (hex being 1/6th turn to the next point). Then turn the slot to that
point, then tighten the jamb nut. In doing so often the adjuster will creep
tighter slightly and cause the adjuster to tighten up. What you need to do
as you tighten the jamb nut is do kind of an isometric exercise where you
are holding the adjuster against rotation with equal and opposite force of
the rotation of the jamb nut! This may take several practice attempts. As
soon as you have tightened the jamb nut just double check that it did not
creep, the slot aimed at the mark we made 1/6 turn left of contact and move
on the next valve.

The jamb nuts need to be tight and there are a couple of ways to deal with
it;
1: Get out the torque wrench, check the factory spec and torque it down.
Problem is with that is your locked into using a socket so you wont have
the screw driver resisting movement of the adjuster, if the torque was close
it should be OK. If it turned the nut much it may creep the adjuster around
and changed your clearance setting. Thus what you have to do is be very
close by hand before putting the torque wrench on it.
2: Perfect way, fabricate a crows foot type box wrench so you can use the
torque wrench and the screwdriver simultaneously. In doing so there is a
leverage factor that needs to be computed to arrive at a different (lower)
torque spec and you probably need four hands to do it.
3: My way again. Put a nut and bolt together in a vice and torque to the
spec, put the undoubtedly shorter box wrench on it to get a feel for how
tight that is. Repeat a few times and feel how tight that torque feels. Then
set the torque wrench aside and do it by hand.

Now that we are done lets just double check our work, remove the bar from
the rear wheel and rotate the engine forward to the checking points, hold it
there with the rear brake momentarily and confirm‎ a small amount of lash.

Re-assemble dont forget, add coolant, return the toothbrush to its owner,
go ride.