On a 1995 Yamaha Breeze, what are the valve specs? I know you check the clearances with the piston at TDC, but on which stroke, and how do you know when it's on the right stroke?

thanks

 

I'm not at all familiar with the breeze (other than I know what it looks like) but here's some gereral 4 stroke info that can be used on any 4 stroke engine,its how I do my V-8.I'm hoping you can see both valves at the same time.If you can only view them one at a time(from each side of the engine you may need a partner to help you).Anyway roll the engine over slowly(make sure ignition is all shut off).Anyways turn the crankshaft and you will see one valve open then the other then they should both shut just before the piston reaches top dead centre.This will be your compression stroke,you may be able to confirm by some sort of timing marks.Go through the cycles a couple of times until your sure you've got it right as even the best can get confused at times.
Cycles of a 4 stroke
1. piston fires at top dead centre both valves closed(power stroke)
2. piston goes to bottom of cylinder and exhaust valve should open as the piston starts its way back up(exhaust stroke)
3.Exhaust valve should close as piston nears the top and the intake valve will open as the piston starts its way back down(intake stroke)
4.As the piston starts its way back up to TDC the intake valve will close and both valves will remain closed(compression stroke) You can hold your thumb over the spark plug hole to confirm good pressure.As the piston goes back down to BDC and starts back up the exhaust valve will open and the whole cycle will repeat.
< by carefully following the engine through a couple of revolutions you can determine which valve is which (because of where it opens in the cycle) and you will also know which stroke your on.
<You can check the valve clearances a couple of ways.If you can confirm your exactly at top dead centre on compression stroke (by timing marks) then you can do both valves with the engine sitting right here.
<If your not sure if your exactly at top dead centre then make sure the intake has just closed with piston slightly passed TDC and the piston just starting back down(adjust intake valve) roll the engine over until the exhaust valve has opened and then shut.When the piston is going back down and the exhaust valve has shut and hasn't moved for a bit then you can adjust it.
<Its hard to give you an exact point in the stroke of when the valves will open and close as this is controlled by your camshafts duration and is slightly different in every vehicle but it should be very close to how I described it.The biggest concern is too make sure the valve you are adjusting is not just starting to open or hasn't completly closed.Sorry I have no clue what your clearances should be.

 

thanks for the info. they say you should be able to wiggle rocker arms a little on compression stroke, whereas on exhaust stroke, they will be tight. there is an easy to access timing mark on m/c that's easy to line up, but you're info on quad may prove extremely helpful.

 

I agree with being able to wiggle rockers slightly on compression but I don't agree with checking for tightness on exhaust stroke.It would depend where exactly on the exhaust stroke the camshaft is sitting. Of course the exhaust rocker will be tight if its starting to apply pressure on the exhaust valve so this isn't a good time to check it for looseness or you could get a false reading if its already starting to apply pressure to the valve.Also why would the intake valve tighten up while the engine is still on the exhaust stroke(unless it was very near the end of the stroke and the camshaft has lots of overlap which is unlikely in a non race engine).In racing engines with camshafts designed for high rpms the valve openings can actually overlap slightly to take advantage of the extra amount of time that they are open but I really doubt this is the case with your breeze as it tends to kill low rpm power.I would just set the rockers to the recommended clearance on tdc of compression stroke,roll the engine through a few cycles so both valves can open and close a few times and then recheck your clearances.Hope I'm not being too confusing
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I believe you check both valves on the compression stroke.

 

Yup,right at TDC and not before.Make sure that intake valve is fully seated[img]i/expressions/face-icon-small-wink.gif[/img]

 

I believe it is the same as my 04 grizz 125. On the passenger side of the engine is 2 black plastic plugs, remove those and in the small one is a timing mark. The largr one is access to a 3/4" nut to turn the engine over by hand. Remove the spark plug the 2 valve covers (15/16" wrench) and align the timing mark on the compression stroke. As you turn it over and look in the small hole you will see an H and the a dash, The dash is the timing mark. There will be a little play in the valves if you are on the compression stroke, If not turn the crank 1 full revolution. The valve specs are on a decal under the seat and it is very simple.

 

thanks for that, it will make it a lot easier. I searched the yamaha forum and found an old post that gave the specs as .004 Ex, and .005 Intake. Is there an "H" and a timing mark? there's gotta be something to line it up to. should be obvious when I look i would think.

 

As you turn the engine over and look through small hole you will see an H and right after it a dash. The dash is the timing mark and there is a mark on the case also so line up the dash with the mark on the case. You can verify it with a small screw driver in the spark plug hole to feel the piston. It is simple. On the Grizzly 125 I had to take the floor board off< But I am not sure about the breeze. The whole process only took 1/2 hour to 45 min. and mine were in spec. When checking the specs be careful not to confuse millimeters with thousandths. The specs under the seat are in millimeters.

 

my specs definitetly are NOT under the seat (may have worn off, not sure). what does yours say for specs?