Horizons Unlimited - The HUBB

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-   -   should valves be oily? (https://www.horizonsunlimited.com/hubb/yamaha-tech/should-valves-be-oily-50027)

Flyingdoctor 2 May 2010 22:33

TDC is only critical for ignition timing as the spark has to be a few degrees before TDC to ignite at the correct time. The gap between the valve and rocker arm is constant over quite a few degrees so as long as there is a gap and you can see the line in the small window then that should be OK. The old trick was to put a dowel or metal rod in the sparkplug hole and watch it reach the maximum. If you do this make sure that no debris is left in the bore or the dowel etc doesn't get crushed. Using gauges in inches is fine just find a converter online to find the correct setting. As you say a 6 thou feeler is too tight but so it should be as that's outside the spec. You need to use a smaller gauge, or combination of the smaller ones to make 4 thou which is 0.10mm or 5 thou which is 0.13mm.

Osmund 3 May 2010 08:51

1 Attachment(s)
Here is a pic that might help youAttachment 3261
You have to move very slow when closing in on the last mark, the "T", or you will roll past it

Jens Eskildsen 3 May 2010 08:56

You should also be ablo to just spin the wheel and watch the valves, when the intake valves are openening, the exhasut is closed, and you can adjust them (exhaust) and the other way around.

kentbiker 3 May 2010 21:09

Quote:

Originally Posted by Jens Eskildsen (Post 287471)
You should also be ablo to just spin the wheel and watch the valves, when the intake valves are openening, the exhasut is closed, and you can adjust them (exhaust) and the other way around.

Not quite! It's often the case that the inlet valve starts to open just as the exhaust valve closes, known as valve overlap. Just stick to the book method - after all, it works!

Geoff

Jens Eskildsen 3 May 2010 21:36

No offence, but as this thread shows, it can be wery hard to get all the things lined correctly up the first couple of times, using the method in the manual.

This works too, and gives a much wider "area" where you can adjust. You can see with the naked eye when valves are not into play, so I really cant see the problem. Have you personally seen valve overlap on the xt600, or are you "making" up a problem? Even if this was the case, and you are stupid enough to not see the valves move, you could do the adjustment, when the other valves are wide open. Or is that also a problem?

Come on, lets all be friends instead =)

I find it easier and quicker, it might not work for you, but it does for me. That doesn't mean its wrong does it?

Were all trying to help, and theres different approaches.

kentbiker 3 May 2010 22:45

Quote:

Originally Posted by Jens Eskildsen (Post 287549)
No offence, but as this thread shows, it can be wery hard to get all the things lined correctly up the first couple of times, using the method in the manual.

This works too, and gives a much wider "area" where you can adjust. You can see with the naked eye when valves are not into play, so I really cant see the problem. Have you personally seen valve overlap on the xt600, or are you "making" up a problem? Even if this was the case, and you are stupid enough to not see the valves move, you could do the adjustment, when the other valves are wide open. Or is that also a problem?

Come on, lets all be friends instead =)

I find it easier and quicker, it might not work for you, but it does for me. That doesn't mean its wrong does it?

Were all trying to help, and theres different approaches.

I'm sorry Jens. I wasn't being dismissive of your method, just giving out the warning, that's all. I'd need to see a valve timing chart to know if there's any valve overlap or not. But there could be. I will stick to my point though, which is that when you're learning something new it's best to learn the correct method. That way, no risks. I did also suggest to Bergspre that he go to the thread for downloading the manual. That could make his life easier all round.
Either way, you're right in that all advice has a value so please don't let me discourage you from passing it on. :thumbup1:

Kindest regards,

Geoff

bergspre 4 May 2010 23:03

Well I thank you all for trying to suggest, different approaches can often help understanding the concept behind it all.

I already have the manual + the clymer manual + the owners manual.

When i watch the valve I see that it moves upward and closes. When it reaches the top theres a part where I turn the engine and the valve seems to not move, is this a safe moment to set the gap?

As I understand the valve closes and stays there for a while(while turning engine) then it goes down again/opens up. So, if it stops at the closed position it should be safe to adjust it once you see that it stopped moving, is my theory based on all you guys's info..

bergspre 4 May 2010 23:32

I tried to make a little chart of how I see it at this moment..it may be wrong so feel free to comment.
http://img202.imageshack.us/img202/7...losophy.th.jpg


kentbiker 5 May 2010 10:26

Quote:

Originally Posted by bergspre (Post 287702)
Well I thank you all for trying to suggest, different approaches can often help understanding the concept behind it all.

I already have the manual + the clymer manual + the owners manual.

When i watch the valve I see that it moves upward and closes. When it reaches the top theres a part where I turn the engine and the valve seems to not move, is this a safe moment to set the gap?

As I understand the valve closes and stays there for a while(while turning engine) then it goes down again/opens up. So, if it stops at the closed position it should be safe to adjust it once you see that it stopped moving, is my theory based on all you guys's info..

Once the valve has closed, as you describe, then the piston will be moving upwards towards top dead centre, trying to compress the fuel/air mixture. This means the timing mark visible through the small hole on the LH crankcase will soon be in sight. Keep turning the engine, either with the rear wheel or a socket on the nut on the end of the crankshaft (anti-clockwise), and when you can see either the F or the T, then all four valves can be adjusted at this point.
Hope that helps,

Geoff

bergspre 9 May 2010 09:25

Thanks for all the help guys :)

Finally spent the day yesterday and adjusted the valve.
It actually feels much "tighter" now, especially from 3500-5000rpm and a bit stronger, which is strange,the valves wasnt that much off except one of the exhaust valves that was 0.01 more then max. Its less noisy above 3000rpm then before.


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