Servicing - valve clearances

[abraxas]

The last service i paid the dealer to do. I know for a fact he didn't do it properly.
I have the manual and it's a very long list of things to do, including valves.

How crucial is this? I am on 60 000km so perhaps it's time?

Any advice appreciated ....

[Elm]

After 40,000 KM you should perform a valve clearance procedure. This is a very important task, because if the clearances aren't within standard those valves could come into direct contact with the piston! Or the air-fuel ratio will be disrupted!



Remember that there are 4 pistons and 16 valves in an FZ6 engine. Can you imagine what would happen if all those valves and pistons were working out of alignment? Your timing would be ruined! We're talking lost compression, poor air-fuel mixtures, excessive exhaust and extra wear.

Valve clearance jobs are very expensive. I know people who've had bent valves and ill engines because they didn't perform this task. It's not dreadfully difficult, but there are lots of steps involved. If your dealer didn't do the job properly, why are you letting him get away with it?? It's a very important job! It would be the last thing I'd want to go wrong.

[Guitar Man]

I'm planning on doing mine next week at the regular scheduled interval. I would not put it off much longer. If your valve clearance goes to zero you could have some serious engine problems. The valves wear in and loose some of their clearance and that is why you need them checked at 26,600mi. If you are mechanically inclined just follow the manual step by step. If you don't think you can do it find a reputable shop that will do it for you. Better to pay a little now than a lot later.

[chemicalsmile]

There's a pretty nice write-up with links to pics here

[wolfc70]

Originally Posted by Elm

After 40,000 KM you should perform a valve clearance procedure. This is a very important task, because if the clearances aren't within standard those valves could come into direct contact with the piston! Or the air-fuel ratio will be disrupted!



Remember that there are 4 pistons and 16 valves in an FZ6 engine. Can you imagine what would happen if all those valves and pistons were working out of alignment? Your timing would be ruined! We're talking lost compression, poor air-fuel mixtures, excessive exhaust and extra wear.

Valve clearance jobs are very expensive. I know people who've had bent valves and ill engines because they didn't perform this task. It's not dreadfully difficult, but there are lots of steps involved. If your dealer didn't do the job properly, why are you letting him get away with it?? It's a very important job! It would be the last thing I'd want to go wrong.

Usually it is not that severe. As the vlaves slam shut over time the clearance between the camshaft and the adjuster can become too tight, allowing the valve to not fully seat and you loose compression and power. If this scenario goes on long enough, you can burn a valve.

The other thing is that the clearance between the cam lobe and the adjuster (in this bike it is an inverted bucket with shims) can become larger, then your valves are just noisey, as no damage will occur with this scenario.

Most likely at the 26,000 mile mark, no adjustment is going to be needed, but checking the clearances is easy and is well worth the time to do it. Just mark down the clearances of all 16 valves and only replace the ones out of spec. Most bike makers say tou need to pull the cams to remove the shims, but sometimes you can sneak the shims out past the cam lobe. Just buy the bucket tool from the dealer to release the shims. You can do it with a scewdriver, but you have a better chance of scratching a wear surface doing it that way.

Unless something severly wrong with the cam timing, the valves are not going to hit the piston. Below is a picture of how to measure the clearance. Yes it is on a V twin, but the idea is the same on all mechanical tappet engines.

[The Rayman]

Originally Posted by chemicalsmile

There's a pretty nice write-up with links to pics here

It is quite involved for sure. I've read that a lot of folks who checked them said they were in spec way after the recommended interval. Anyone here find theirs out of spec?

[Fred]

Originally Posted by Elm

After 40,000 KM you should perform a valve clearance procedure. This is a very important task, because if the clearances aren't within standard those valves could come into direct contact with the piston! Or the air-fuel ratio will be disrupted!

All of the above information is wrong.

The interval is 16,000 miles, which is 25,759 kilometers.
http://www.mcnews.com/mcnews/article...599vsFZ603.pdf

EDIT: My numbers on the interval are wrong. That's what I get for trusting the internet.

The valves will not hit the pistons.

The air fuel ratio will not be disrupted.

What will happen.

If valve clearances alter, your throttle bodies will be out of synch. The engine may have more vibration than normal. You won't know it until you've set things back to ideal, because the vibration would have snuck up on you over thousands of miles.

The valve clearances will slowly close up. As the clearances close, the time the valve is open increases. This isn't a good thing, because it's opening earlier and closing later. It's not going to cause the valves to hit the pistons, but it is throwing your valve timing away from optimal.

Second, the valves are in contact with the valve seats for less time. They shed heat through the seat, so they will get hotter. Eventually you can burn valves from this, and the valve face can break off of the stem in a worst case scenario. At which point the broken off part of the valve can hit the piston. You'd have to REALLY neglect the bike for this to happen.

The FZ6 has a shim under bucket valvetrain. What this means in plain english is that the valve clearance will rarely change. It's a very good system.

When you check the clearance at 16000 miles, write down the clearances and any changes needed. Save this data. Look at it during the next check and the one after. It's likely that you'll see the valves aren't changing their clearances after the first adjustment. They've settled in and will be good for a long, long time.

What Elm is thinking of is a broken cam chain. In this scenario, the valves stop (some of them still open) and the pistons keep moving. And that does bend valves. That's a totally different scenario and is unaffected by valve adjustments.

Fred

[Elm]

Originally Posted by Fred

All of the above information is wrong.

The interval is 16,000 miles, which is 25,759 kilometers.
http://www.mcnews.com/mcnews/article...599vsFZ603.pdf

--The HAYNES manual says every 40,000 KM in EUROPE, every 42,000 KM in the US.

The valves will not hit the pistons.

--You're right. The pistons will hit the valves instead.

The air fuel ratio will not be disrupted.

--So you're saying there will be NO LOST POWER?? With incorrect shim measurements???

What will happen.

If valve clearances alter, your throttle bodies will be out of synch. The engine may have more vibration than normal. You won't know it until you've set things back to ideal, because the vibration would have snuck up on you over thousands of miles.

The valve clearances will slowly close up. As the clearances close, the time the valve is open increases. This isn't a good thing, because it's opening earlier and closing later. It's not going to cause the valves to hit the pistons, but it is throwing your valve timing away from optimal.

Second, the valves are in contact with the valve seats for less time. They shed heat through the seat, so they will get hotter. Eventually you can burn valves from this, and the valve face can break off of the stem in a worst case scenario. At which point the broken off part of the valve can hit the piston. You'd have to REALLY neglect the bike for this to happen.

--Hmmmm.....sounds like something that happened to TWO people I know, THREE if you count myself. We didn't neglect our engines.

The FZ6 has a shim under bucket valvetrain. What this means in plain english is that the valve clearance will rarely change. It's a very good system.

--True.

When you check the clearance at 16000 miles, write down the clearances and any changes needed. Save this data. Look at it during the next check and the one after. It's likely that you'll see the valves aren't changing their clearances after the first adjustment. They've settled in and will be good for a long, long time.

What Elm is thinking of is a broken cam chain. In this scenario, the valves stop (some of them still open) and the pistons keep moving. And that does bend valves. That's a totally different scenario and is unaffected by valve adjustments.

Fred

..........I'm getting tired of this. Now I can see why Raid the Revenge took off from this place.

[Fred]

Originally Posted by wolfc70

Most bike makers say tou need to pull the cams to remove the shims, but sometimes you can sneak the shims out past the cam lobe. Just buy the bucket tool from the dealer to release the shims. You can do it with a scewdriver, but you have a better chance of scratching a wear surface doing it that way.

Good info, Wolf. I saw your response after I wrote mine.

I've done the valve shims on my K-75 the way you describe. Given a set of picks and a tool to hold the valve open, the shim can be pulled out easily.

Unfortunately on the FZ6 it is necessary to pull the camshafts. Instead of being on top of the bucket like in the picture you posted, the shim is underneath it. This setup is even more stable than the shim over bucket setup that your pic and my K-75 have. But it's a pain in the butt to change the shims.

On the other hand, old school pushrod valves with screw adjusters are very easy to adjust, but you have to do it more often. Win some, lose some.

[poorwboy]

Originally Posted by Elm

..........I'm getting tired of this. Now I can see why Raid the Revenge took off from this place.

HUH.