It came time to check my valves. The four clearances on the vertical cylinder are within spec. The two clearances on the horizontal intake are within spec. Then I tried checking the opener clearance on the horizontal exhaust valve and my smallest feeler gauge won't even slide in - that gauge being .0015" or .038mm. I have the dots on the flywheel sight glass lined up for TDC and I can feel the horizontal piston at the top of the cylinder with a screwdriver.
Is this common? Does it just mean I need to sand down the opener shim? If so, how much would you suggest sanding off initially? I suppose logic would say to sand off the amount of the spec, which IIRC is .004"?
Thanks in advance for the help! [beer]
can you spin or rotate the shim using your fingers?
Quote from: ChrisK on February 13, 2014, 03:23:39 PM
It came time to check my valves. The four clearances on the vertical cylinder are within spec. The two clearances on the horizontal intake are within spec. Then I tried checking the opener clearance on the horizontal exhaust valve and my smallest feeler gauge won't even slide in - that gauge being .0015" or .038mm. I have the dots on the flywheel sight glass lined up for TDC and I can feel the horizontal piston at the top of the cylinder with a screwdriver.
Is this common? Does it just mean I need to sand down the opener shim? If so, how much would you suggest sanding off initially? I suppose logic would say to sand off the amount of the spec, which IIRC is .004"?
Thanks in advance for the help! [beer]
What specs are you using?
Likely that the horizontal exhaust closer is way out of spec, correct that first, then re-check the opener.
It'll take you a long time to sand .004" off of an opener, best to buy (or trade) one that's nearer (or correct) size.
Yes, pretty easily
Why I ask this is because if it can spin but my .0015 will not fit I call it a .0005 and calculate from that. It has not failed me yet ;-) I am on the road until next week so I can't give you the changing spec.
FWIW I use the check the opener, write that down, push the fork check it again and do the math for the closer spec. May not be the method Speed does.
Speeddog, I didn't notice your reply before I sent my last reply. I'm using the specs in the Haynes manual.
Scooter I'm also using the method of measuring the opener, pushing the arm down, re-measuring, and doing the math to get the closer clearance.
So should I remove the closer shim and measure with a micrometer? Then proceed from there?
I don't have a Haynes manual, so I've no idea what they say....
Yes, measure the closer clearance, then measure the closer shim (better results with a tool and micrometer).
Then get and install the new closer shim, confirm closer clearance, then see what the opener clearance is.
Then fix the opener clearance.
The .0015 gauge won't slide into the closer either, but the shim will spin with a little effort. So can I assume the closer is just barely too big? So get a smaller closer, re-measure and then address the opener as needed?
So you push the closer rocker down, and you still can't get the .0015 gauge in?
Correct. It gets slightly easier to spin the shim, but not a whole lot.
Sounds like that closer is reasonable, but I'm suspicious something isn't correct.
Usually, if the clearances were set correctly, like .001" on the closer and .005" on the opener, then after a good bit of riding the closer could be .005", and the opener would be .001".
What wouldn't be correct, off the top of your head?
Should I just try to get the right size opener and see where I'm at?
I'd pull the belts off, as I normally do, and remove the opener shim just to make sure all I've got 'in the picture' is the closer.
Rotate the cam to the 'tdc' position.
Then push down on the closer, and directly measure the clearance between the rocker and the shim.
I'll remove the belts and opener and report back tomorrow.
What's the best way to remove the clip holding the rocker arm in place? I tried using a 90 degree pick that I have but no luck so far.
I use an exhaust spring hook tool.
I use a 90 degree pick.
Took the opening shim and belts off. Pushed on the closing arm and still couldn't fit the .0015" gauge in.
Quote from: ChrisK on February 14, 2014, 02:37:49 PM
Took the opening shim and belts off. Pushed on the closing arm and still couldn't fit the .0015" gauge in.
If you push down on the closer rocker arm, can you turn the shim?
Is it turning the valve as well?
Cam turns freely between the points that it starts opening the valves?
Yes I can turn the shim, to be honest I can't be certain the valve stem wasn't turning. I don't think it was, but I can check that later. Yes, the cam was able to spin freely.
Yes, the shim spins, the valve stem stays still.
That closer sounds OK.
Has the engine been run recently?
Yeah, about a month ago, ran great until I had that problem with the starter clutch remember?
Also, after I got the new starter clutch and Keihins installed I started it and ran it in the garage for about 5 minutes, ran great.
OK, that's good.
I'm just concerned that there's some debris on the valve seat corrupting the reading.
Very unusual to have both clearances so small on the same valve.
I remember when doing my valves for the first time I would get different readings on the same shim. Be sure the cam is in the correct spot in rotation. Can't remember which either at the highest point or the lowest point (when the rocker touches the shim).
I'm pretty sure that's not the case Memper. I measured the vertical cylinder first and everything checked out, then I spun the wheel again around to TDC. I can now feel the piston in the horizontal cylinder, can't in the vertical cylinder. Unless there's something else I don't know about.
If the belts are off it doesn't matter where the crank/piston is when checking clearance as long as you bring the piston up to TDC before removing the closer shim.
The valve will drop into the cylinder if you don't.
Just line up the pulley mark on the cam.
Yep, done that too.
When the valve seat wears, the opening clearance gets smaller and the closer gets larger. They both have to change. They are connected to the same valve. Now if the shims where change previously by someone ??
I don't know the previous history of the bike. All I know is they haven't been adjusted in my two years of ownership.
I wet-sanded my opener so I now have somewhere between .003 and .004" of clearance. The closer is at what I'll consider .0005".
Thanks guys.
Quote from: ChrisK on February 15, 2014, 03:43:24 PM
I wet-sanded my opener so I now have somewhere between .003 and .004" of clearance. The closer is at what I'll consider .0005".
Thanks guys.
Is this an intake or exhaust?
I was talking about the cam pulley not the crank pulley.
But whatever, I probably don't know what I'm talking about. [laugh]
Exhaust.
Quote from: ChrisK on February 15, 2014, 06:20:12 PM
Exhaust.
I set exhausts to .005" on openers.
Maybe Speeddog or Brad use a tighter spec. :-\
I do 2-valve air cooled exhausts at .005" on openers.
Its time to check the Valves for me. Last time I did it was about three years ago. Rather than posting a new thread about "isn't there a sticky about which marks are for TDC?" maybe someone can steer me to where it is? Thanks.
MD2.0:
take off the belt covers, take out the spark plugs . . . turn engine until the crankshaft pulley mark matches teh one on the rh case, the horizontal cyl should be in TDC . . . now is just a manner of preference, start either with the exhaust or intake . . . then turn 270° to get vertical on tdc . . .
Well I got the Belt covers off. (Took em off 2 years ago [laugh]) got one spark plug out and I'm pretty sure I have the mark. I guess those little round dots in there must be magnets for the flywheel.