Fabio

On 12/23/2023 at 12:50 PM, Ben1098 said:

You have ONLY a "hash line" to mark the TDC for the V-Twin engine cylinders.  Just like the service manual error for the early 750/920 CC Yamaha Virago (motorcycle) you can time the cams and thus the valves to be closed at TDC---ON COMPRESSION STROKE----- BUT be  phased wrong.......meaning it will run but have  "rough"  power strokes.    The IGN timing is triggered off the crank and will fire a few degrees BEFORE TDC every time.  With a 4 stroke engine, the crank turns at 2X speed as the cam.  There are TWO times the T comes up WITH THE VALVES CLOSED as required so the piston doesn't bend the valve faces.......COMPRESSION and OVERLAP (Exhaust CLOSES and the Intake starts to OPEN).  This is called the Wasted Spark IGN setup.  The cylinder can ONLY fire on the Compression stroke ....turning into the POWER stroke BUT the fuel air mixture is "dead" burnt gasses (being pushed out (Exhaust) and not Compressed before a new fuel air charge is sucked into the cylinder (Intake)).

Back to the phase of the 2 individual Power strokes.  The phase angle of the IGN spark pulses (timed off the crank) is determined by the V bank angle.  BMW and Wings have a Boxer type engine where the "twin" cylinder is 180 deg apart on the crankshaft rotation.....shared coil pack......one cylinder is on Compression (fire spark) while the "twin" is at Overlap (waste spark) and vice versa.  British VERTICAL twins had the both pistons on the same throw (both pistons rise and fall at the same time) and as a result the single cam lobes (push rod engine) are 180 deg apart using a separate gear reduction and dual points.  This makes the firing 180 deg apart (cam) or 360 deg (crank) and the distinctive smooth sounding exhaust note-----BUT a horrible vibration that sheds tank chrome, gauges, fenders. etc.  H-D, Yamaha, SOME Honda Shadows (2 versions of their V-twin) (like your motor) have the cylinders spaced around 45 to 60 deg of separation.  I'll use 45 deg in this instruction set on how it works.

Cam markings are for BOTH the respective TDC of the crank, BUT at 1/2 the rotation speed, they determine the Compression and Overlap cycle......Lobes both down is obviously the Compression.......Lobed spaced around 90 deg is the overlap (Exhaust valve is CLOSING) and the Intake valve is OPENING).  You have to pick the correct cam position for the each of the TDC cylinder marks on the crank.  You have 2 cylinders, 2 cams, 2 cam chains, 2 cam chain tensiioners.

Timing has to be in the correct sequence or degree of separation between spark firing on the Compression TDC of the Front and Rear cylinders for a smooth run.

You CAN have the cylinders fire at only 45 deg apart as the crank turns in normal rotation.  You will have 2 power strokes 45 deg apart and then "coast thru an additional 675 deg  of DEAD TIME  of the 720 deg (2 x 360) 4 stroke cycle.

Exhaust note will be pop--pop (0--45 deg)----------------------------OVERLAPx2------------------------------pop--pop (720--765 deg)---------------------------------OVERLAPx2)-----------------------------------------pop--pop etc.  This will "run" but is not an "even power output" the flywheel can smooth out.  To prevent this assembly build error, most of the engine suppliers have the crank marked T1 and T2 for cylinders 1 and 2 and not need a manual to decode their marks.

The smoothest power strokes are 180 deg apart....ALMOST impossible with a V-Twin.  So go with the next best thing...........time the cams at the greatest angle of separation.  For 60 deg V, the fire points you want are 0 and 300 deg.......NOT 0 and 60 deg.  For 45 deg V, the fire points you want are 0 and 315 deg.  That said using this rule of thumb, you can time any V-Twin cams without service manual information.

USE CARE TO KEEP THE CAM CHAINS TIGHT ENOUGH TO PREVENT JUMPING OFF THE LOWER CRANK GEAR.  NO CAMS AT THIS TIME.

STEP 1:  Determine the direction of rotation (CW or CCW facing the crank) of the crank.  Usually have a circle arrow.....BUT if none, rotate the crank and feel for and listen for the starter rotation.  Turning the crank in the forward direction (normal after starting) will be "free" and rotating backwards will engage the one-way starter sprag bearing and turn the starter thru the reduction gears (harder to turn).  Your 2nd picture looks like an "half arrow" pointing to the direction of rotation??????Maybe????

STEP 2:  Rotate the crank in the same direction and bring up any timing mark "T" in the window.  Use a copper wire to determine and select which piston is UP and TDC.  IF REAR cylinder is TDC (up) continue another 45 deg of rotation until the FRONT cylinder is TDC (up) and the "T" in the window.  I like to use a 3/8" breaker bar and 12 point socket (with spark plugs out there is no load) and align the handle with the cylinder that the piston is UP at TDC.  NO guess as to which cylinder I am working on.  Personal preference is to start with the FRONT cylinder.  I usually add a paint mark to the FRONT  "T". 

STEP 3:  Rotate (IN THE SAME DIRECTION) toward the REAR cylinder "T".....should almost be a complete rotation of the crank.......315 deg.........the desired smooth firing order.

STEP 4:  Rotate (same direction) the crank the 45 deg to the "T" (with now a paint mark).  Here it is hard to Install the FRONT cam with both lobes just touching the cam rockers.  Install the cam with the lobes down and valves closed.  Double check the alignment of  the index marks on crank and cam.

STEP 5:  Install the tensioner (wind up and hold to load).  Tighten the 2 bolts to hold the chain tensioner.  Release the wind up.  DONE.  The cam and chain are now held in position to the crank "T" mark.

STEP 6:  Rotate the crank thru the 315 deg to the next "T" REAR cylinder at IT'S TDC.

STEP 7:  Install the REAR cam with both lobes down (compression) and the valves closed and align the index marks like before.

STEP 8:  Install the cam chain tensioner like before.

STEP 9:  Double check the REAR alignment marks like before.

STEP 10:  Slowly hand rotate the crank thru 2 complete cycles (4 rotations).  From where you left the crank in Step 6, rotate 45 deg to the Front Cylinder OVERLAP TDC.  The Exhaust valve should just be closing and the Intake valve just opening.  Rotate 315 deg to the OVERLAP of the rear cylinder.  Rotate until the FIRE position of TDC Front cylinder comes up in the next 45 deg.  Check the timing marks alignment.  REPEAT AGAIN to be sure.  This is to check valve timing AND for NO binding with valve/piston INTERFERENCE.

That's it!!!!                        Install spark plugs in their boots and lay on engine.....watching for the spark.  If you turn on the IGN SW (KEY ON) only------NOT START------and rotate the engine over by hand, you will see a spark for every T but only one is usable at the Compression TDC.  The OVERLAP spark is wasted on the burnt exhaust gas AND no compression.  My final check is to use the crank with the starter and put a finger over the open spark plug holes.  You should have a "semi-suck" on finger tip spark (overlap) and a nice compression blow off POP when the plug fires for the Power stroke.....................for each cylinder.

This is great info. thanks Ben!

Now my question is, between the 2 marks, which one im going to refer to?

Also, how can i figure out the that the first cylinder will be on compression stroke without having to remove the cam?

Again, thanks for all that info, now that i have some time between the holidays ill be spending some time on this, trying to se if i can get it running

Thank for having me here!

New proud owner  of a 13 hisun HS 800 and here is some back story.

I got the machine apart, most of the head and timing chain and some electrical.

Now, i put everything back together using the original service manual but now im stuck on timing the engine.

When i look at flywheel i have 2 marks , but both looks like it says "1" .

I'm confusing in how do i set the timing on this machine and if anyone has done anything like that and could shed some light on this, it would be great.

im using the motorcycle doctor instruction but even on his , show that i should have T1 and T2 making on flywheel.

here some pictures of those marking