Timing advice needed.

[muzikill]

I'm getting myself confused around timing when rebuilding the k3 engine and am wondering if you guys can give me some definitive advice on making sure i get it right. Ive read all the manuals and about 90% sure but a 2nd opinion would help.

One thing that bothered me when checking the front cyclinder clearances is when i aligned the F mark the cam lobes werent pointing away from each other and the haynes manual said just turn it again to the F mark to make them do this ..... when i am rebuilding the engine im worried i will get it wrong (manual says make sure the cylinder is at TDC on the compression stroke 'not the exhaust stroke') by checking the camshaft lobes - eh it's the camshafts i will be refitting!

-ive been getting some advice from 'squirrel_hunter

"Yes the F mark is used for the clearances as well as the R mark. But when removing the cams only use the F mark.

If you rotate the engine to the F mark and the cams do not have the lobes pointing away from each other on the front cylinder then rotate the engine again 360o to get back to the F mark and they will be. When the engine is at F and the front cylinder lobes are not pointing away then the rear cams are set for removal. The cams are designed to be removed at TDC for each cylinder when they are not putting any pressure on the valves.

As for rebuilding, its the same principle. Use the F mark to get the engine to the TDC at the front and install the cams. Keeping pressure on the front cam chain and holding the rear chain taught rotate the engine to install the rears. I wasn't sure about this myself, but if you consider that before the cams are installed they have no pressure on the valves and so the engine has no timing. If you get the front piston at TDC on the F mark then so long as when you install the rear you've rotated a full turn then the timing will be correct. "


The F mark is used for front & back so how do i know if the front is at the right position?, also should the piston be 'up' or 'down' when installing them!

It's doing my nut in. (maybe i should read over some guidance on how a v-twin works)

Edit - i thought 180 degrees from the F mark (half way to it again) the rear would be TDC but it cant be if you use the F mark to do the rear as well!

[muzikill]

http://forums.sv650.org/showthread.php?t=102993

I found this thread .....

And Zadar posted this....

if cams are out there is no compression or exhaust stroke,just stroke.
when you put cams in you basically tell engine which stroke is what.
in other words it does not matter,you can start anywhere you want,front or rear,any crank revolution.you just make sure where ever you start next cylinder is one crank revolution apart and both cylinder cams are set at F mark(not R for rear).R is TDC but not where you set cams at.cams are set at F mark for both cylinders(one revolution apart).R mark is only to check valve clearance.

hard to get my head round it - i thought you'd have to get the timing right in line with the piston positions eg. one up - one down - vice versa

[zadar]

The cams are designed to be removed at TDC for each cylinder when they are not putting any pressure on the valves.

The F mark is used for front & back so how do i know if the front is at the right position?, also should the piston be 'up' or 'down' when installing them!

It's doing my nut in. (maybe i should read over some guidance on how a v-twin works)

Edit - i thought 180 degrees from the F mark (half way to it again) the rear would be TDC but it cant be if you use the F mark to do the rear as well!
Cams are not designed to be removed at TDC for each cylinder.
They are designed to be removed on F mark, period. F mark has nothing to do with TDC for rear cylinder.

Every time that F mark is in window front piston is at TDC. It is not up once and than down when you align F again, it is always up when F is aligned.
So, align cams on whatever cylinder you want to start with when F mark is aligned. Once that cylinder is done turn crank one revolution, align F again and than install cams in other cylinder. That is all there is to it.

Manual tells you to do at TDC on compression stroke because manual explains one cylinder at time. If you only taking cams out of one cylinder you need to put them back on compression stroke. When both cylinder cams are out there is no compression and exhaust stroke, you only have TDC. Once you put one cylinder cams in you told engine which stroke is compression and which exhaust because motor turns twice for one cam revolution.

So, pick cylinder, align F and go from there.

[zadar]

And rear cylinder is never at TDC when you setting cams or taking them out. Ignore TDC for rear piston like it does not exist. Only time you using TDC on rear (which is R mark) is when checking valve clearances.