TOPIC:

I've got a question for all you experts out there. can a engine run with the cams 180de. out? I just got thrue putting in new shims, and was reinstalling the cams as I had taken them out. The intake cam #2 lobe was pointing straight up and the #3 exhaust lobe was straight up. This had the timing arrows pointing at each other. And yes the timing marker on the ignition is at 1-4 T. Considering that both 1&3 and 2&4 have ignition spark at the same time, it is concevable it should run. It was running when I took it apart and yes the lobes where as mentioned. My compression was between 135 and 150 with only a slight increase with oil. The bike is a stock 78 650B2. My intension is to install the cams properly, but is there any thing I should be aware of?
Thanks
Bill

WHOOOOA!! 1-4 2-3 are the pair couples
wasted spark means that one cylinder is on overlap and the other cylinder is on compression event both get sparked at the "F" mark...then they alternate... ok?

now start at the crank sitting lined at 1-4 "T" mark
cam tensioner OUT ok?

put the EXAUST cam in where the #1 lobe points to the front of the bike. there is a line on the chain wheel that lines up with the head surface after pulling slack out of the cam chain from the crank.

the intake cam with the #1 lobe pointing towards the back of the bike and also has a line on the chain wheel that lines up to the top head surface.

There is a specific chain pin count but I do not have the number here now

#1 cylinder is on the far left as you sit on the bike OK?
this is generally how ALL inline 4 bikes cams go in
gently torque in prooper order
re install cam chain tensioner and turn crank (by hand) 2 full revolutions YES 2 FULL REVOLUTIONS with a tool !! NO ELECTRIC START-- NO KICK STARTER

all 3 marks should line up cam"IN" cam "EX" with head surface crank "F"with timing line
if not readjust
be patient do it right

can a engine run with the cams 180de. out?

If you had rotated the crank one more time till it lined up on the marks again, then the marks would have been lined up properly

Keep in mind the cams make "one" revolution for every "two" revolutions of the crank

Thanks Steell
With this in mind am I right in thinking I should rotate the engine one time in order to have the valves and pistons aline properly with true timing marks?
Bill

I just answered my own question. T of 1&4 brings the pistons up to top dead center. With the cams out the valves all close, so it should be fine to re-aline the cams properly with out any problems. Thanks every one.
Bill:lol: