removing valve cover

My bike sat for quite a few years before i spent alot of time and money getting it where it's at now. The thing has always had a piston slap or kind of a tapping in the engine, but runs pretty well, idle is slightly rough but when warm it can sustain idle.
I decided that it would probably be a good idea to check the valve clearances since i'm certain they are probably incorrect. I have no proof that they've ever been checked or adjusted in the 28,500 miles the thing has been on the road.
I used my allen wrench and got all but 4 of the bolts out. One in the front and center bolt, in a very awkward place. The holes are stripped out, dont ask me how, thats the way i got them.

Any suggestions on how to remove these bolts without damaging anything else.

 

Try a Torx bit mounted in a small ratchet.
They can sometimes be tapped into the head of a rounded off hex or allen head bolt and will grab the edges of the flats enough to remove 'em.

Good Luck - remember it's an adventure!


Dan

 

i like the torx bit, may i suggest using it in a impact driver

 

thanks, it's certainly worth a try

 

I would Sacrifice an Easy-Out.

Grind-off the end of the Easy-Out that will provide the best "Grip" when inserted into the stripped-out hole.

Lightly tap it in -- to insure you have some good "Purchase" on the fabricated Easy-Out.

Apply a firm and steady pressure on the handle of Vice Grips locked to the Easy-Out, as you begin to withdraw the fastener so that your next move will apply sudden turning torque to break-loose the stripped-out item ...

Then, give the Vice Grips a deliberately well-struck rap with a hammer handle to apply sudden "Break-free" force to the tools already under light pressure.

The sudden whack should loosen the fastener sufficiently to undo it by hand.

That should do the trick.

 

i got 2 of them off with visegrips and then i used my dremel, cut a straight slot and used a monster screwdriver and got em. All but 2 of my clearances were right but everything looks nice and clean.
I am kinda lost now, the clearances are all too tight and i dont know exactly how to remove the shims with the lobe, i think it's the lobe, on top of the shim. I'm gonna do some forum searching for awhile i guess.

 

To remove shims:

The shims sit in a "bucket". The bucket has a 1/8" wide notch in it. Rotate the bucket so it points toward the centerline of the head. Rotate the engine so the lobe depresses the valve.

You need to hold the valve open. There is a special tool available that slips behind the cam and bolts to the valve cover screw hole. You can also remove the spark plug and snake something up between the valve and seat to prevent it closing. If you opt to put something in the valve make sure it won't break and won't damage the valve and seat. I'd thin a piece of 12-14 gauge solid wire with the insulator on it would do the trick.

Now rotate the engine so the cam is off the shim. If you use the custom tool make sure you rotate so the lobe comes toward the centerline of the head. If you rotate the other way the lobe will contact the tool and damage the head.

Now with the cam off the shim use a small screwdriver in the notch in the bucket to pop the shim out. I used a dental pick which worked well. The shim thickness should be written on the bottom and is in 1/1000s of a mm. Use a shim chart or your fingers and toes to calculate the correct shim thickness you need. Put old shim back in (writing down) while you pull the other. NOTE: They tend to trap oil underneath and not seat well until the lobe presses on them. If that happens it will make a sharp "Pop" and shoot a big drop of oil right between your eyes. Place a rag over camshaft to prevent oil in eye.

Order replacement shims and install.

 

ok, i've studied your answer pretty closely and have one question, probably an extremely dumb question but i'd be more dumb not to ask. How do i rotate the engine? I understand everything else but i'm not entirely sure how to rotate the engine

I'm hoping it's very simple.

 

Simple it is.

Just remove the timing cover (4 screws) which is the forward engine cover on the left side, and use a wrench to turn the rotor (which has flats in the center to allow a wrench).

There should be an arrow to show which direction to turn, but I didn't find one on mine.

 

ok i'll see what i can do

 

Hold it ... hold-on!

If I read your Post right ... you say: "They're ALL too tight!"

Well ... if EVERY ONE of 'em is going to need to be adjusted ...

Do the Math.
Get the Shims. (Although sometimes you can just "Move-around existing Shims ... THIS TIME ... I get all the NEW Right ones.)

Then ...

Binding the Cam Chain to the Cam Drive Sprockets with a couple of real heavy-duty Plastic Ties ...

Loosen the Camshaft Bearing Caps and Lift the Cams.
Do them All in ONE SHOT.
No muss.
No fuss.
No worrying about Valves, Seats or Damaging anything.

Without the Special Tool you should do it this way even if you only had to do one or two!

Set-up the TIMING to #-1 TDC and Observe ALL the TIMING MARKS ... and then do all of them in one-fell-swoop!

 

Make a table of your shims and clearances.


.................... 1......................2...................3......................4
_______________________________________________________

Intake******.006**********.012********.012**********.008
Clearance

Intake******.026**********.026********.025**********.025
Shim

Required****calculate******calculate****calculate*******calculate
Intake
Shim



Exhaust
Clearance

Exhaust
Shim

Required
Exhaust
Shim

 

ok, i'm trying to fully understand Rick's post. So the way you are talking about, i dont need to remove the timing covers or open the valves manually, i just need to remove the camshaft bearing caps and i can easily access the shims.

The camshaft bearing caps. Are those the covers with 4 bolts, looks kind of like a master cylinder cap, right next to the lobe?

 

xjyamaha, RickCoMatic thought you said all but 2 shims were out of wack, I read your post as all were correct except 2.

If all but 2 are correct don't remove your cams, you will be farther ahead digging into how to replace the 2 shims via the regular method.

If you do some searching here for "shim replacement" or "valve shim" here's a few I dug up.

One previous post where I made a tool similar to what's available in the market place...
http://www.xjbikes.com/Forums/viewtopic/t=641.html

This thread shows the zap tie method....
http://www.xjbikes.com/Forums/viewtopic/t=463.html

This thread discussed where to purchase shims.....
http://www.xjbikes.com/Forums/viewtopic/t=3134.html

I also did a google search for "Yamaha valve shim chart" and came up with this how to link....
http://www.surenet.net/~verhey/Valve_ad ... page1.html

Trying to find the "chart" I came across this link which step 5 tells you how to calculate the required shim using some math. Just need to substitute the correct numbers from your engine specs.
http://www2s.biglobe.ne.jp/~arch/fz/tips/valve.htm

I almost forgot that a previous member posted an online shim calculator that he posted, here's his link....
http://www.cs.toronto.edu/~relu/shimcalc.html

As you can see there is a lot of info on this subject, different ways of changing the shims, you have to go with what you feel comfortable with.

 

Rick was right, i made an error. All of them are wrong but 2, they are all too tight.

 

how far off are they ?
sounds like a winter job to me
summer is for gathering parts and riding
mine are all .001 to .002 tight too but they are just going to have to do till
november

 

ok, i got the shims off and all the measurements are taken. I listed a chart below.

All i can use from the old shims is one, so if anybody has a need for any of the shims i pulled off and will swap me for some of my needed sizes i'd be thrilled, thanx

Hope it's not too difficult, i couldn't get my excel chart to attach


......................................Inlet..........................Outlet
1
opening____________ .10__________________ .15

shim_______________300___________________270

required shims_______290__________________265

2
opening_____________.03__________________.15

shim_______________305__________________270

required shim________290__________________265

3
opening______________.10______________.15

shim________________300______________ 265

required shim_________290______________260

4
opening____________zero_______________zero

shim_______________300________________270

required shim________285_______________255

 

xjyamaha, what are you using for specs on the intake?
I get one size different across all your intake shims required.
1, 2 & 3 should be 295 required
4 should be 290 required

the cold intake valve clearance should be 0.11 ~ 0.15 mm (0.004 ~ 0.006 in)
the cold exhaust valve clearance should be 0.16 ~ 0.20 mm (0.006 ~ 0.008 in)

 

i have an 81 650, the specs differ from a 750

 

I'd worry about #4, both the waiting and whether your shim values are correct.

Since you have 0 clearance now the valve may not be down on the seat. You may need a thinner shim than you are calculating.

I'd try that 265 shim in both the intake and exhaust of #4 to see if I could get a measurable gap.

 

My info is from Yamaha service manuals.
I was quoting specs for a 650 engine, but looking at the 750 specs now, they are the same!

 

Shim calculation is an art. The chart is a good guideline but the proof is always in the pudding. I've used the chart to set up and then double checked clearances after all the parts settled down (a quick warm up is usually all you need). Check the clearances again and make any neccessary adjustments.
Another wisdom nugget, what is printed on the shim is not always the size. Use a micrometer to verify your thickness, regardless of the printed numbers.

 

MiCarl:
I put the 265 shim in the intake and exhaust on 4 and that gave me more clearance than i knew what to do with, so i know that with the right shim i will get clearance......

 

HMMMM. Your chart says you need a 255 on the exhaust side of #4, yet your statement seens to indicate a 265 is way loose.

 

i made an error, just the inlet was way too loose. The exhaust had a gap, but still too tight.