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Author Topic: Pushrod adjustment - unable to set the inlet pushrod  (Read 840 times)

Machismo

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Pushrod adjustment - unable to set the inlet pushrod
« on: April 04, 2013, 07:59:02 AM »
Hello friends

Hope you all had a good Easter!
While I was adjusting the pushrods of my 2008 AVL, found that I was never able to get the inlet valve to the lowest position before adjusting it for play.

This is how I tried arriving at the adjustment:
1. With the engine cold(and ignition off), crank the kick starter until the compression builds up and kept looking at the tappets to reach the lowest position.
2. Use the adjuster nut to make up for the play.

While I was able to get the exhaust tappet to the lowest position, the inlet never reached the same point as the exhaust.
Am I missing something?

Well, I got another query as well:
If I were to remove the air-box and use one of those hose pipes used in UCE 500 that connects
the air filter box and the intake manifold, would it be okay?
Am fed up with the low quality hose pipes that degrade so often and the leakage in the airbox(at the bottom).
Would like to know if this might amount to any change in the behavior of the bike.

Thanks!

High On Octane

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Re: Pushrod adjustment - unable to set the inlet pushrod
« Reply #1 on: April 04, 2013, 01:31:51 PM »
I haven't worked on the AVL motor, so someone correct me if I'm wrong.  But every motor I HAVE ever worked on, the valve needs to be fully closed before you can make any adjustment to it.  You need to rotate the motor slowly with the kick starter and with the rocker covers off.  Watch the valve you want to adjust as you are slowly turning the motor with the kick starter.  As you turn the motor you will see each valve/rocker assembly move up and then back down.  As the valve you want to adjust closes, and the opposite valve JUST starts to open is the position of the valve when you want to make your adjustments.  Hope this helps.

Scottie
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DanB

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Re: Pushrod adjustment - unable to set the inlet pushrod
« Reply #2 on: April 04, 2013, 02:40:08 PM »
^+1.  You need to be at TDC to adjust both the exhaust and inlet.  I suggest using a small dowel down into the plug hole to watch what your piston is doing and watch the pushrods at the same time. Mark the dowel when its at its lowest and at its highest positions.  This will help you visualize what the engine is doing. You'll see the inlet side moving as the piston swings through its cycles.

Check this video out.  Its mostly the same process for AVLs. http://youtu.be/4bmgJPyCUNU
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2006 AVL Electra

EnfieldJake

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Re: Pushrod adjustment - unable to set the inlet pushrod
« Reply #3 on: April 04, 2013, 03:33:56 PM »
Your method for adjusting the valves is fine. Bring them to TDC and adjust. The pushrods on my 2006 AVL are not the same length. If you look at the attached pic you'll see the adjuster on the exhaust valve is lower in relation to the intake valve. They will not be at the exact same height to each other. In the pic, my engine was at TDC for adjustment. Note: My adjusters may look slightly different than yours due to mine having been upgraded to CMW's/NField Gear's Z91503 AVL Pushrod Adjusters. Good luck!
Jake

barenekd

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Re: Pushrod adjustment - unable to set the inlet pushrod
« Reply #4 on: April 04, 2013, 05:10:45 PM »
To make sure the you have TDC (Top Dead Center), put the bike on the center stand, pull the spark plug, put the bike is gear, preferably 2nd or 3rd. Get a piece of wire (About 7" long) and put it down the spark plug hole keeping it as vertical as possible, (make sure the wire is long enough not to drop down into the hole!) then rotate the rear wheel and you will see the wire moving up and down with the piston.
To make sure you have the proper TDC, the compression/firing stroke, watch the lifters. If they aren't moving at TDC, you should be on the right stroke. If they are both moving as you cross over TDC, you need to rotate the crankshaft 360 degrees.
FOr a quick initial check before you put the wire down the spark plug hole, put your thumb over the spark plug and rotate the engine with the wheel and when you feel pressure building under your thumb, you should be coming up on the compression stroke. Remove the thumb and put in the wire and continue to find TDC.
Bare
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Arizoni

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Re: Pushrod adjustment - unable to set the inlet pushrod
« Reply #5 on: April 04, 2013, 07:12:19 PM »
I think bare nailed it.
On the firing stroke neither valve should move as the piston approaches TDC and even passes it.

If either valve is moving at all as the piston approaches TDC the engine is on the exhaust/intake cycle.

I also like the idea of using the rear wheel to 'bump' the engine thru its cycles although I think it works best with the transmission in high (5th gear).
That gives the least engine movement for any incremental of movement of the rear wheel.
Using the rear wheel also lets you rotate the engine backwards a little if you overshot the TDC position by turning the rear wheel backwards.
Jim
2011 G5 Deluxe
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KB8ANY

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Re: Pushrod adjustment - unable to set the inlet pushrod
« Reply #6 on: April 05, 2013, 02:12:46 PM »
Yo:

The first time I adjusted the valves I saw the intake was tight (but the exhaust was not), too.  The service man at the dealer told me this is typical.  Your intake tappet never reached the same level for 2 reasons: first, the two are offset; second, the intake may simply be tight (i.e., needing adjustment).  The valve guides/seals are made of very soft metal and deform over time.  Also, if you study the valve train, you will see that as this happens the tappets get tight, not loose.

The easiest way to see what is happening is to take the right-side engine cover off.  That way you can actually watch the cams and tappets.  Do it the first time; from then on you probably won't have to bother.

1.)  Take the right cover off.
2.)  Take the plug out.  That way you can turn the motor easily.
3.)  Put the bike into 5th. gear.
4.)  Use a wooden dowel, and stick it into the plug hole until it touches the top of the piston.  I have read some guys post that they use a long screwdriver - I don't advise that.
5.)  Stand on the left (gearshift) side, and gently bump the engine in the running direction with the rear wheel, all the while fiddling the wooden dowel with your free hand so that it does not get bound in the hole and break.  With a little bit of practice, you can feel when the piston is coming up to, crossing, and going down from, TDC.  Go right to TDC and stop.  Quite a bit of slop either side of TDC is okay - when you look at the cams you will see why.
6.)  Go to the right side, look to see if the cams are on the base circles of their respective cams.  If not, rotate the engine until they are on the base circles.  If you took the dowel out of the engine, you can do this from the right side as you stand there looking at them.
7.)  Adjust the tappets.
8.)  Put everything back together.

The first time you do this, you will have to replace the right-side engine cover gasket.  This will be the last time you ever have to replace it if you use a single-edge razor blade to scrape the metal surfaces.  Scraping them like this preps them for the new gasket, and leaves gasket material in the tiny holes in the surfaces so that the new gasket material doesn't meld into them.  (Do this every time for every gasket, and you may never have to buy a new gasket again.  I found this to work even with the head gasket.)

There is nothing magic about adjusting the tappets.  All that is necessary is that the tappets are on the base circles of their respective cams.  This is the point at which the valves are "relaxed," so that adjusting really is adjustment.  With the right-side engine cover off you can actually see why and what is going on.

Good luck.

Paul

1 Thump

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Re: Pushrod adjustment - unable to set the inlet pushrod
« Reply #7 on: April 05, 2013, 04:48:23 PM »
For three dollars this is very good value for money. Minimizes the risk of dropping something in the chamber and is certainly more precise than any dowel or screw driver (they move around on the piston surface ....you will never be certain of TDC). You will probably not need to adjust timing but this is good for that as well. Just make sure to engage the decompressor while you kick it through or use the tire spin (may need two people) method.

http://nfieldgear.com/enfield-store/top-dead-center-tdc-finder-tool.html

Machismo

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Re: Pushrod adjustment - unable to set the inlet pushrod
« Reply #8 on: May 03, 2013, 10:27:04 AM »
Thanks a ton folks. Using a mix of the techniques suggested here, I was able to satisfactorily adjust the tappets. But I still think this exercise felt much easier on the cast iron I previously owned.
By the way, I shed the decomp and changed the tappet window cover to that of a cast iron.
Making an old style decomp on the head is a planned activity for the future.