TIPS ON ADJUSTING THE VALVES
Overview
Most of this information has been taken from posts by various forum members and compiled here.
A Yamaha mechanic for 25 years told me that normally Yamaha valve lash almost never needs adjusting.
I think maybe he was being truthful that time. The following is a collection of posts from various owners.
I have edited and embelished it.
Checking/adjusting the valve lash isn't complicated but is tight and difficult for old men with bad backs, bad eyesight, and fumble fingers.
If not for the accessibility you could probably adjust the valve lash in 10 minutes.
I use .004 in. intake and .006 in. exhaust, +/- .001.
The lash doesn't have to be perfect but most important is not to get them too tight or the valve seat face will burn. If too loose, they tap.
The valve lash should be adjusted toward the middle or lower end of the lash specification or the rockers will tap on the valve tips.
Realize that, as the parts wear, the lash will tend to increase.
After adjusting I make sure a .003 feeler gage will slide in the intake lash and a .005 gauge in the exhaust.
Make Some Tools
To make the feeler gauges easier to use I bent some 6 inch long 10-32 machine screws from an old electric motor into L shapes.
I attached the feeler gauges with 10-32 nuts and lock washers.
I cut the gauges off so they were about 1 inch long then sharpened the tips with a grinding wheel.
This made the job much easier. The long screws are used as handles.
I bent them so I could get them in the tight spaces.
After adjusting one valve I rotated the feeler gauge on the screw so I could adjust the other. It worked very well.
I had to make a tool to turn the set screws. They have small square heads and nothing I had would fit.
I made a tool similar to another member here on the forum for the small square 3mm or 4mm (don't know which)
for the adjuster screw and used a 10mm open end wrench for the lock nut.
It's tricky getting it there. Sometimes I had to feed the wrench through the right side to get a good hold but it all worked out OK.
To make the tool I used some old spade wood drill bits. The kind that that are flat with a triangular point on the end.
Grind the point off the end and grind the end flat. Then, with a Dremel or whatever, cut a notch in the flat end.
Keep filing or grinding on the notch until it just fits the set screw.
If you don’t have a big Allen wrench to turn the crank you can put the bike on a jack.
Put the bike in 5 th gear and turn the crank by turning the wheel.
Stick a plastic tube down the spark plug hole so you can tell when the piston is at top dead center with intake and exhaust valves closed.
I took advantage of the gear lash to nudge the piston in place.
When I looked at the fly wheel timing marks they were not lined up perfectly but that doesn't matter.
I went slightly past top dead center cause I knew the valves are closed until the piston is near the bottom of the stroke.
[My opinion is to set it to the timing marks like the manual states. Editor]
Suggestions to Ease The Task
You will need to remove the gas tank so refer to the instructions elsewhere on this WIKI.
I just drained about 2 to 3 quarts of antifreeze from the drain plug on the bottom of the radiator.
This will drain the two top radiator hoses that have to be removed.
This way when you put everything back together you just have to fill the radiator before you put the tank back on.
A couple of zip ties need to be cut to move the wiring harness around a little to make room.
I did all the work from the left side.
If you don’t have the bike up on a jack you could put a paver brick under the kickstand to level the bike out a bit.
Use zip lock bags for all bolts to keep things organized. First time took me all day, about 7 hours.
The next time within two days to fix my screwup took about 4 to 5 hours.
Another suggestion.
The front cylinder is easier since there is a bit more room to work in and it’s easier to get the feeler gauges in.
The rear cyclinder is a real bear. So I chose to do the front first and then the rear.
The manual suggests this anyway. There are only three pages for valve adjustment.
The rest of the directions talk about removing and draining a bunch of stuff that really doesn't need to be done.
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