Valve adjustment procedure

[sumran]

I just got back from a great tech day in Tallahassee, Florida. I was there for about eight hours on Saturday, but this is a multi-day camping, wrenching, eating, story-telling event. I have to reserve the weekend for next years event. I hope others more familiar with the whole event will report about it. Many thanks to Kevin and Traci (hope I spelled that right) for hosting and to the others that helped in the event.

We had rebuilt a set of carbs and were adjusting valves in preparation for the carburator adjustment. As we were moving the engine around to TDC to make the adjustment, someone mentioned that they don't adjust the valves at TDC. He moves the engine until one valve is fully open, then adjusts the closed valve next to it. It was late and we still had a full carb adjustment to do and a two-hour ride to get home, so I did not get to follow up on the conversation.

I do not know enough about the design of the cam to know if this procedure would work well. I sometimes have difficulty getting the OT mark precisely in the window when I am working by myself.

How do you position the engine for valve adjustment?

[26667]

w an allen wrench (4mm , I believe) and a flash light. Plugs out, 2nd gear, front cover off (ground strap removed). With the light in my right hand so i can see into the hole, and my left hand turning the motor, it's easy to see the mark and come up to it slowly and hit it right on the screws. Even if I miss it, it only takes a few seconds to come around to that side again.

Besides the f marks, there are a couple other warning marks; nicks and discolorations on the side of the flywheel that appear just before the OT mark on mine. After a few times around I've got 'em memorized.

.

[20774]

I used to use the rotor bolt but was concerned about stripping it, especially if the plugs are in. Certainly taking them out eliminates the pressure build up, but for me, the less times I have to remove the plugs the better!!

Since the valve covers are off for adjustment, you can watch them work to identify when a cylinder is approaching TDC on the compression stroke. Get the rear tire off the ground (...insert Reynolds thread here :lurk ...), put the bike in 4th or 5th gear, and get behind the bike and rotate the wheel, while watching the intake valve (I do the left one first). When it begins to close, stop turning the rear wheel. Now, go sit by the left side timing window and reach in and lightly bump the rear wheel forward, watching the timing marks. You'll see the F, the S, and then you creep up to OT. Check for gaps on the rockers, spin the pushrods, etc. Then go about the process of check/setting the clearance.

For the other side, you need to turn the engine 360 degrees. You can go back to the rear tire and watch the right intake valve. When it begins to close, go to the left side of the bike and bump the engine until you see OT. Go over to the right side and set the clearances.

Once all done, repeat the process for a couple more revolutions and recheck the clearances. Button things up if they all check out.

[brickrider]

Kurt has just described the exact procedure that I used so many times without trouble of any kind. It's about as fail-safe as it gets.

Print his Post. Then go to your bike and follow his description to the letter, "dot the i and cross the t".

Couldn't be easier.

Ride Safely,
BrickRider

[benway]

why do you put it in gear?

w an allen wrench (4mm , I believe) and a flash light. Plugs out, 2nd gear, front cover off (ground strap removed). With the light in my right hand so i can see into the hole, and my left hand turning the motor, it's easy to see the mark and come up to it slowly and hit it right on the screws. Even if I miss it, it only takes a few seconds to come around to that side again.

Besides the f marks, there are a couple other warning marks; nicks and discolorations on the side of the flywheel that appear just before the OT mark on mine. After a few times around I've got 'em memorized.

.

[r60us]

why do you put it in gear?

Try it on your bike without putting it in gear, and the result will be self explanatory - shade tree mechanics 101 .:)

[benway]

hes turning the engine with the rotor bolt, not the rear wheel, so why does he put it in gear.

must be a lot harder to turn

Try it on your bike without putting it in gear, and the result will be self explanatory - shade tree mechanics 101 .:)

[sumran]

I used to use the rotor bolt but was concerned about stripping it, especially if the plugs are in. Certainly taking them out eliminates the pressure build up, but for me, the less times I have to remove the plugs the better!!

Since the valve covers are off for adjustment, you can watch them work to identify when a cylinder is approaching TDC on the compression stroke. Get the rear tire off the ground (...insert Reynolds thread here :lurk ...), put the bike in 4th or 5th gear, and get behind the bike and rotate the wheel, while watching the intake valve (I do the left one first). When it begins to close, stop turning the rear wheel. Now, go sit by the left side timing window and reach in and lightly bump the rear wheel forward, watching the timing marks. You'll see the F, the S, and then you creep up to OT. Check for gaps on the rockers, spin the pushrods, etc. Then go about the process of check/setting the clearance.

For the other side, you need to turn the engine 360 degrees. You can go back to the rear tire and watch the right intake valve. When it begins to close, go to the left side of the bike and bump the engine until you see OT. Go over to the right side and set the clearances.

Once all done, repeat the process for a couple more revolutions and recheck the clearances. Button things up if they all check out.

This is the procedure I have used, except I have rotated the wheel from the back while I have someone else read the marks for me. I need to use the wheel bumping technique, so I can see the marks while I move the wheel.

[Bob_M]

I put a dab of paint on the side of the flywheel next to the OT mark. This way I can see the mark when I am at the back of the bike turning the wheel.

[Isamemon]

just a thought, for future reference
next time you have your starter out, lightly sandpaper the flywheel at all the marks. use different color paints and mark the different flywheel timing points

cleaning the flywheel helps easily see all the points, and you can get a better blob of paint on the mark , then reaching through the timing hole with a small brush

otherwise, I pull the plugs when setting my valves, so I dont think I would have the problem of stripping the rotor bolt

[PAULBACH]

I copied and saved this explanation from someplace on the forum:

- I start on the left side. Ensure that the left side is at TDC on the compression stroke. You can do that by watching the valve train action and figuring out when the intake valve closes. At that point, you should be approaching TDC on compression. Another way is to remove both plugs and put your thumb over the open hole...feel the compression.
- Begin watching in the timing hole, left side near the cylinder and to the rear. Bump the rear wheel slowly, looking for the F-mark, then the S-mark, and then OT.
- Set the valves.
- While still on the left side, rotate the engine 360 deg by watching the flywheel. The next time the OT mark shows up should be TDC on the compression stroke for the right side.
- Set the valves.
- Rotate the engine several times and recheck your work.

Having the head bolts torqued to proper specs (around 25 ft-lbs) is required, but at least be sure the bolts/nuts are tight. Don't overtighten these...you could pull out the studs. Snowbum mentions that... The gaps you mention are correct, that is 0.006 inches or 0.15mm.

[20774]

The quote that Paul included mentions gaps of 0.006in or 0.15mm...that's for the intake valves. 0.008in or 0.20mm would be for the exhaust valves.

[sumran]

I have been running .20mm and .10mm and have been happy with the result. I know that many people like .15mm on the intake.

It seems that no one who posted uses the method described in the initial post. Bumping the wheel while I look in the timing window will solve the problem that created my question.

[co_g30]

I used to use the rotor bolt but was concerned about stripping it, especially if the plugs are in. Certainly taking them out eliminates the pressure build up, but for me, the less times I have to remove the plugs the better!!

Since the valve covers are off for adjustment, you can watch them work to identify when a cylinder is approaching TDC on the compression stroke. Get the rear tire off the ground (...insert Reynolds thread here :lurk ...), put the bike in 4th or 5th gear, and get behind the bike and rotate the wheel, while watching the intake valve (I do the left one first). When it begins to close, stop turning the rear wheel. Now, go sit by the left side timing window and reach in and lightly bump the rear wheel forward, watching the timing marks. You'll see the F, the S, and then you creep up to OT. Check for gaps on the rockers, spin the pushrods, etc. Then go about the process of check/setting the clearance.

For the other side, you need to turn the engine 360 degrees. You can go back to the rear tire and watch the right intake valve. When it begins to close, go to the left side of the bike and bump the engine until you see OT. Go over to the right side and set the clearances.

Once all done, repeat the process for a couple more revolutions and recheck the clearances. Button things up if they all check out.

just make sure to secure your centerstand to the front wheel with a sturdy strap so the bike does not move forward as you rotate the rear wheel. There's a chance of it sliding off the center stand and toppling over on its side. DAMHIK. :doh

[sumran]

just make sure to secure your centerstand to the front wheel with a sturdy strap so the bike does not move forward as you rotate the rear wheel. There's a chance of it sliding off the center stand and topping over on its side. DAMHIK. :doh

I hope you are just passing along a general warning you read about in a magazine!:whistle

[co_g30]

I hope you are just passing along a general warning you read about in a magazine!:whistle

unfortunately I was stupid enough to do it without securing the bike as mentioned.

[ducatipaso]

I can't understand why everyone is making this so damn complicated!
I do my valve adjustment with every oil change.

1) put bike on centerstand
2) put pan under bike
3) remove drain bolt, let drain whilst you...
4) remove valve covers
5) remove plugs
6) with bike in 3rd or 4th, rotate rear wheel until a valve opens then closes, continue until it starts to open again then back it up enough so there is no load on the rocker
7) adjust to your desired spec. i do the .1 .2 specs. repeat 4 times.
8) swap out oil filter
9) replace oil plug, valve covers, spark plugs then fill with your choice of oil
10) enjoy revitalised airhead

in 20 years of riding airheads, I have never ONCE looked at the timing marks to make these adjustments, and never had an issue.

[dduelin]

Randy,

How was I there too and did not talk with you? I got there at 11:30 Sat. and left at 2:30. I took a circuitous route 210 miles from my house to Kevin's. All I did at the barn was tighten the LH carb spigot and balance the carbs, eat a sandwich, then ride home the same way except it rained all the way to Live Oak.

[20774]

5) remove plugs
6) with bike in 3rd or 4th, rotate rear wheel until a valve opens then closes, continue until it starts to open again then back it up enough so there is no load on the rocker

in 20 years of riding airheads, I have never ONCE looked at the timing marks to make these adjustments, and never had an issue.

Curious why you remove the plugs if don't really have to? :dunno The only reason I would do that would be if I was turning the engine by the rotor bolt...using the rear wheel is enough to over come the compression.

"Until a valve opens"? Do you watch the exhaust valve? I don't see why you would just pick any valve to watch. The most likely valve to watch is the intake valve. But I don't understand the part about watching a valve open, close, and open, and then backing up...seems kind of complicated.

What if your valves had closed up to zero clearance? You wouldn't be able to find a situation where there was no load on the rocker. I guess then you would have to look at the timing marks?

Seems to me the safest thing to do IS to use the timing marks...if you're timing marks are off, then there might be bigger problems then finding OT. If you've gone so far as to remove the plugs, put your thumb over the hole, rotate the rear wheel until you feel compression on your thumb, continue to rotate the wheel while you watch for OT in the window...you're sitting right there!! No back and forth...just rotate forward to OT and your done.

Well, it is a personal motorcycle and there are several ways to skin a cat...

[sumran]

in 20 years of riding airheads, I have never ONCE looked at the timing marks to make these adjustments, and never had an issue.

But look what happened. All your fairings came off and your handlebars are bent down.:laugh

[paulfinney2]

Yeah, the DAMHIK is published at least monthly, and sometimes weekly, and all of us Airheads subscribe. Subscription rates may vary.

[bikerfish1100]

i was taught years ago to look for valve overlap- when intake starts to close, and exhaust starts to open on the same cylinder. that will be darn close (if not dead on) to OT for the opposite side cylinder. i then "dial it in" with OT mark (or arrow on cam gear on an oilhead, as it works jsut fine on them as well).
Kurt- since its easy enough to remove plugs (check gap, clean up or replace while you're at it) and then more easily rotate the wheel, why not?

fwiw- never heard of the method mentioned by the OP. nor would i attempt to use it.

[20774]

Kurt- since its easy enough to remove plugs (check gap, clean up or replace while you're at it) and then more easily rotate the wheel, why not?

fwiw- never heard of the method mentioned by the OP. nor would i attempt to use it.

Since the spark plug holes are such a critical set of threads, I don't remove them unless I have to. (I'm involved with engineering work associated with the health of military aircraft structure...one of the problems with aircraft maintenance is everytime you remove a fastener to check for a crack/damage, there's the real chance that more damage will done to the hole.) Yes, pulling plugs and checking them is a good thing. I believe I have one side where the plug is a little hard to hand tighten or loosen...probably build up of gunk on the threads as I've used anti-seize in the past. I would like to get away from anti-seize but figure I'll wait until I have the heads off for the top-end (I have 90K on the top-end) and just chase the threads off the bike.

As for the Original Poster's method, I hadn't really thought about that approach. It means that the engine has to be turned twice for each side to get one or the other valve to the point where the clearances can be set. If you do it the "standard" way, you turn the engine only once per side and set both valves at the same time.

[ducatipaso]

I pull the plugs because it's easy, gives me an opportunity to inspect them and understand how my engine is running, and make it even easier to turn the engine over. It's a quick procedure, and I use a small amount of antisieze crayon on them when I put them back.

Again, I don't know why this is being made so complicated. The cam has plenty of space on it where the lobe is not riding on the pushrod... it's not like you've got a 10 degree window to work in... in fact, the opposite applies.

Try it sometime. Rotate, watch valves go up and down... approximate the midpoint between close and open, then adjust. Done.

[ducatipaso]

But look what happened. All your fairings came off and your handlebars are bent down.:laugh

damnit! I KNEW something was wrong!

[miltown]

Will you just do it the way Kurt says. It is easy and painless. If it is your first time it might take a few times like anything else. Stop asking why you have to remove spark plugs and rotate the wheel in 5th gear just do it. It works and takes all but 20 minutes tops once you know what your doing. The hardest part is getting the flash light positioned in the hole to see the mark. Sorry taking it out on you because I'm frustrated with the brakes on my bike and I'm also sure there is a lot of old posts on this subject.

paul
83 R80RT

[keelerb]

Bikerfish, is this right?

"I was taught years ago to look for valve overlap- when intake starts to close, and exhaust starts to open on the same cylinder. that will be darn close (if not dead on) to OT for the opposite side cylinder."

If the intake was open and is closing, aren't you headed for the compression stroke? So the exhaust valve won't open at that point...?

Not an expert on this by any means - hence the question! Thanks - B

[sumran]

Will you just do it the way Kurt says. It is easy and painless. If it is your first time it might take a few times like anything else. Stop asking why you have to remove spark plugs and rotate the wheel in 5th gear just do it. It works and takes all but 20 minutes tops once you know what your doing. The hardest part is getting the flash light positioned in the hole to see the mark. Sorry taking it out on you because I'm frustrated with the brakes on my bike and I'm also sure there is a lot of old posts on this subject.

paul
83 R80RT

Already done. The earlier advice allowed me to make the operation a one-person job, which is all I was after. The method I asked about in the original post was not one I have used, rather it was a different approach that raised my curiosity. I also expected to (and have) gained some insight into the cam design.

Sorry about the brakes. I'll try to give some help on that thread. :thumb

[bikerfish1100]

Bikerfish, is this right?

"I was taught years ago to look for valve overlap- when intake starts to close, and exhaust starts to open on the same cylinder. that will be darn close (if not dead on) to OT for the opposite side cylinder."

If the intake was open and is closing, aren't you headed for the compression stroke? So the exhaust valve won't open at that point...?

Not an expert on this by any means - hence the question! Thanks - B

give it a try. watch one side (L or R, doesn't matter). when both valves are moving (one in, other out), go to the other cylinder, and see what you can do. look in the window- OT will either be right there, or incredibly close.

[keelerb]

That sounds right, Biker - when the exhaust is closing and intake opening, you're about to start the intake stroke on that cylinder, so that piston is near TDC - and the other one is beginning its power stroke, so both its valves are closed. It was the reversal of intake and exhaust that threw me. Thanks - B

[sumran]

give it a try. watch one side (L or R, doesn't matter). when both valves are moving (one in, other out), go to the other cylinder, and see what you can do. look in the window- OT will either be right there, or incredibly close.

Thanks for the useful tip!

[miltown]

Thanks for understanding. Bad day will see about tonight.

paul

[DaveSlash5]

I just read this thread and y'all are talking about moving the valves by moving the rear wheel? Just push down on the kick start lever with your hand and you can look in the hole for the OT at the same time. Unless you have one of those modern airheads of course...

[sumran]

I just read this thread and y'all are talking about moving the valves by moving the rear wheel? Just push down on the kick start lever with your hand and you can look in the hole for the OT at the same time. Unless you have one of those modern airheads of course...

:rofl :rofl :rofl

[paulfinney2]

To make it easier to spot the OT marking, take a q-tip, spray paint a tip white, and rub it in the indentation of OT, then clean the surrounding area. Might even add a little dot in advance of OT to let you know it is coming. Really picks up the light.