Timing Mark

[mack]

So, while I'm cleaning the motor I, rotate the it until I feel where the top of the piston stroke is. I look down at the timing mark and this is what I see. If you look closely, you'll notice that the pointer is not where it's supposed to be. The vacum hose is off. Is this just a matter of moving the pointer. Also, while i'm in the process is there any maintenance I should do to the thing while the cover is off. P.S remember I'm not a mechanic so try to stick to technical terms like, "thing ma bobs" and "do hicky's"

[randy]

What picture?

[mack]

oops

[/IMG]

Thaought I had this figured out

[DGXSER]

Picture link is not working. What your looking for is TDC of No 1 piston, not just any piston, so it coud easily not be on the mark from the "feel" method you described.

If you want to check the mark, pull the spark plug (the thing-a-ma-bob that black thin wire looking thing is plugged onto that is on top of the big metal looking do-hickey) Now put a screwdriver or a coat hanger, or something longer than your hand down into the spark plug hole. Crank the engine over clockwise by hand and watch your gizmo rise and or fall. When it rises up and stops rising, mark that spot on the plate where the pointer is pointing with an erasable marker of some type. Now continue turning the engine until said gizmo starts to drop again, mark that spot as well. The point in the middle of those two marks is TDC of no 1 piston. and that is what should be close to the pointer.

[mack]

Picture

[DGXSER]

Actually, you are pretyt much exactly on the mark!! The C mark is for setting the cam chain tensioner and not timing. The F is the timing mark.

Check Catatonic Bugs signature for access to a manual, looks like you need one.

[mack]

timing

The head is off the bike so there is no problem finding the top of the stroke at no#1, and that is where the picture is taken at.

[randy]

You should be lining up the pointer to the "F" mark. The "T" is for cam timing and the "C" as DGXSER previously wrote is for setting cam chain tension.

[mack]

ya

The piston is at the TDC now, then the pointer is way off. So do I adjust the pointer to match TDC or is this difference associated with what I've heard refered to as dwell?

[randy]

Rock the crank back and forth to make sure you have true TDC. The crank can move a few degrees either way and the piston will not appear to move. If the pointer is still off, reposition the pointer now to correspond with TDC on #1. Line it up with the "F" mark. Each graduation of the plate is equal to 5 degrees. Static ignition timing is 5 degress BTDC.

[Incubus]

Shoot, I wish the timing mark on my XS11F (which runs very, very well) was that close...

Patrick

[mack]

maintenance

Ok, how about any maint. requirements. Anything to check on or do before I put this dude back together and go for a start up.

[79XS11F]

I would not move the pointer unless it was already moved by a PO. If the paint at the base of the pointer to the casing is not broken, then the pointer is at it factory position. Unless it is bent or otherwise damaged it's position should not be altered. There is some Dwell at the top of the pistons stroke where the piston is not really noticeably moving up or down. You may find that the pointer in in the middle of this range. The other thing is that the timing wheel on these bikes is not a "perfect" fit. there is some play there as well. If it is truly off the mark, move the wheel within its free play, not the pointer.
Rob

[TopCatGr58]

That's not entirely accurate!

Hey Mack,

I thought something didn't sound quite right, so I checked the MANUAL, and it confirmed what I thought!

The "T" mark is the TDC indicator mark. The "F" mark is the timing mark, but it's for checking the static ignition timing with a timing light with the engine running, the vac. adv. capped, and idling at about 1K rpm, the "F" mark is appx. 5 degrees BTDC.

IF you'll look closely at the MARKS, you can see and check and measure the spacing for the 20 and 40 degree marks, the same distance will be from the 20 degree mark to the "T" mark, which would indicate "0"/ZERO=TDC. The "F" mark lines up with 5 degrees BTDC.

Having the head off makes it quite easy to see when the piston isn't moving up or down, but there's still a bit of slack where the crank can spin a few degrees before the piston starts to move in the opposite direction, so as has been stated, it looks DARN CLOSE, and unless you have a gauge/micrometer that you can put against the top of the piston to see when it has truly stopped moving, and then also note when/where on the timing plate the piston just starts to move both up and down, then mark the position in between those 2 points would provide a more accurate TDC point.

T.C.

[mack]

I'm learning

Ok several of you pro's state that it's close enough to leave alone. I'll do that. I'm getting antsy about getting the frame back from painting and starting to put it back together. I just want it to fire on the first pass so I don't have to second guess why it didn't. Still waiting for carb parts, going to follow someones advice about replacing the 31 year old coils with new, so I have at least a good starting point there. Anyone know if the vacum advance listed in the tech bulletin is still available? Are there points or anything that should be replaced?