Topic: cb550 with 650 camshaft notch "U" position

[Jimsun]

Im a bit confuse as to how to set the camshaft after doing some more reading into it.

How would I go abouts knowing that i have installed the  camshaft the proper way without taking the cylinder head out? Im not sure if i have it installed 180 degrees. However, from  my understanding, i can remove the sparkplug on #1 and #4 and shove a bbq stick (skewer) to find TDC (highest point) right?

Also, when i set the "T" mark, I had it so that the camshaft "U" is half visible facing forward (3 oclock). However, it's also possible that at another full rotation, the "U" will be facing the backwards at 9 oclock. Some are saying that when piston 1&4 are at TDC (highest point) the notch should be facing to the back of the bike where some say it doesn't matter as it still requires a full 180 degree turn.

a lot of source here
http://forums.sohc4.net/index.php?topic=55613.msg598847#msg598847

"With cylinder 1 at tdc notch in cam should point toward front of bike (which to me also seems like 3 o'clock. I don't know where 9 o'clock comes from. Maybe you can also set the cam at 9 o'clock since cam turns half of crank speed and ignition fires every time piston comes up whether it is a compression stroke or not) Recheck it and make sure you are not a tooth off on the sprocket."
http://forums.sohc4.net/index.php?topic=55613.msg598866#msg598866


"Dont matter a stuff wether the notch points forwards or backwards as long as the crank is on T mark for 1 and 4.

Cam turns at half engine speed so on alternate 1 and 4 T marks it will be front or back"
http://forums.sohc4.net/index.php?topic=55613.msg598895#msg598895

[calj737]

Set it to TDC on #1, notch forward or aft, it doesn't matter. It's a 4-stroke 4. Dave500 has chimed in repeatedly on this and every time he does, one of us overthinks it.

Once installed, take note of the timing marks, rotate the engine 180 and see where the marks are again? Proof it's installed properly. No other consideration necessary.

[Jimsun]

Thanks cal. Whats aft?

Set it to TDC on #1, notch forward or aft, it doesn't matter. It's a 4-stroke 4. Dave500 has chimed in repeatedly on this and every time he does, one of us overthinks it.

Once installed, take note of the timing marks, rotate the engine 180 and see where the marks are again? Proof it's installed properly. No other consideration necessary.

[trueblue]

Thanks cal. Whats aft?

Set it to TDC on #1, notch forward or aft, it doesn't matter. It's a 4-stroke 4. Dave500 has chimed in repeatedly on this and every time he does, one of us overthinks it.

Once installed, take note of the timing marks, rotate the crank 360 and see where the marks are again? Proof it's installed properly. No other consideration necessary.

FTFY Cal , Aft also means rearward.  As long as you have the crank at 1-4 T mark, it makes no difference whether it faces forward or backward, as long as it lines up with the head surface.  The cam turns half a turn for every turn of the crank, so if you think the cam is 180 out turn the crank through one full revolution and it will be where you want it.   

[Jimsun]

Whats fyft? Im confused now. So is it okay to leave it as is or should i have cyl one set at tdc and have the notch face forward? :S

Thanks cal. Whats aft?

Set it to TDC on #1, notch forward or aft, it doesn't matter. It's a 4-stroke 4. Dave500 has chimed in repeatedly on this and every time he does, one of us overthinks it.

Once installed, take note of the timing marks, rotate the crank 360 and see where the marks are again? Proof it's installed properly. No other consideration necessary.

FTFY Cal , Aft also means rearward.  As long as you have the crank at 1-4 T mark, it makes no difference whether it faces forward or backward, as long as it lines up with the head surface.  The cam turns half a turn for every turn of the crank, so if you think the cam is 180 out turn the crank through one full revolution and it will be where you want it.   

[trueblue]

FTFY, means fixed that for you.  If the notch is forwards, you are on #1 firing, if it is rearwards, #4 is firing.  As long as the notch is paralell with the head surface at 1/4 T mark you are golden.  Forwards or rearwards makes no difference  .

[goldarrow]

FTFY, means fixed that for you.  If the notch is forwards, you are on #1 firing, if it is rearwards, #4 is firing.  As long as the notch is paralell with the head surface at 1/4 T mark you are golden.  Forwards or rearwards makes no difference  .

+1 and can repeat this all over again.

And somehow I feel someone might bring up the "180 degrees off" topic....

[Jimsun]

FTFY, means fixed that for you.  If the notch is forwards, you are on #1 firing, if it is rearwards, #4 is firing.  As long as the notch is paralell with the head surface at 1/4 T mark you are golden.  Forwards or rearwards makes no difference  .

The thing is i spun the engine with the kick start without the cam on because i was putting together the engine together. I didnt have the points at the time to spin it from there.

From what ive read, you're saying that at 180 degree its either 1 or 4 firing. However, how would i know without taking the head off if it's installed properly.

[goldarrow]

You don't take the head off, but you can take the head cover off. Once you do, put advancer back on so you can spin it to correct position

[Jimsun]

You don't take the head off, but you can take the head cover off. Once you do, put advancer back on so you can spin it to correct position

I understand. I had it set so that the T mark and the camshaft notch is facing forward. However, i did not check nor did the manual say anything about the position of cyl 1 or 4 when setting the notch forward.

I spun the advancer and placed it at T mark. I opened tappet for cyl one and the removed the spark plug. When valve on 1 is lose (both intake and exhaust), cyl 4 is at tdc

[dave500]

don't get confused with the two t marks,one is for 1/4 and the other for 2/3,be sure to set the cam using the 1/4 t marks,if you use 2/3 the cam will be 90 degrees out.

[Jimsun]

don't get confused with the two t marks,one is for 1/4 and the other for 2/3,be sure to set the cam using the 1/4 t marks,if you use 2/3 the cam will be 90 degrees out.

Im using the "| T | F 1*4" mark. I have it set up so that this T mark (stated previous) and the camshaft notch is facing forward... Im getting confused now with others saying that the T mark should be facing rearwards, forward or it doesn't matter at all when cyl 1 is at TDC (farthest position from the crank)...

[dave500]

as said already forward or rearward doesent matter,fit it to the front,now rotate the crank 360 back to the same 1/4 t mark and the notch will be at the rear,install it to the rear then rotate the crank 360 and itll be to the front,a bit like this?

[Jimsun]

as said already forward or rearward doesent matter,fit it to the front,now rotate the crank 360 back to the same 1/4 t mark and the notch will be at the rear,install it to the rear then rotate the crank 360 and itll be to the front,a bit like this?

All right. I guess it really doesn't matter which way it's positioned then. I just don't want to fire her up and hear danger.

[trueblue]

Ok, I'll try and explain it for you. In an inline 4 cylinder, 4 stroke engine the cylinders are in 2 pairs.  1 and 4 pistons move together and 2 and 3 move together.  When cylinder 1 is at the top so is cylinder 4, only thing is when 1 is at top dead centre (TDC) compression when number 4 is at TDC exhaust and vice versa.  The same is true for 2 and 3.  When 1/4 is up 2/3 are down and vice versa.

The cam moves at half crankshaft speed, in other words the cam turns 180 degrees for every one revolution of the crank, or one cam revolution for every two crank revolutions.  The ignition on these bikes is of wasted spark design, in other words the coils fire spark plugs in pairs, the pairs being 1/4 and 2/3.

The basics of a four stroke engine are for every piston stroke the crank turns through 180 degrees, there are believe it or not 4 strokes for every cycle.  On the first stroke, the piston moves down with the intake valve open, this is the intake stroke.  Next the intake valve closes and the piston moves up on the compression stroke.  The spark plug then fires and the intake charge burns and pushes the piston down, this is the power stroke.  The exhaust valve then opens and the piston moves up on the exhaust stroke.  When the piston reaches the top the exhaust valve closes, the intake valve opens and it starts all over again.  Now they don't open and close exactly at TDC and BDC (bottom dead centre), there is lead in and out as well as overlap, but that is of little consequence in this case.

So in short, the cam makes no difference which way round it is, forwards or rearward, as long as it is timed on the 1/4 T mark on the crank, this is crucial.  With the cam in either forward or rearward, you still have a piston at the top on compression and spark on that cylinder so it will still run. 

[Jimsun]

Thanks for explaining it like im five!!! I understand it now thank you

Ok, I'll try and explain it for you. In an inline 4 cylinder, 4 stroke engine the cylinders are in 2 pairs.  1 and 4 pistons move together and 2 and 3 move together.  When cylinder 1 is at the top so is cylinder 4, only thing is when 1 is at top dead centre (TDC) compression when number 4 is at TDC exhaust and vice versa.  The same is true for 2 and 3.  When 1/4 is up 2/3 are down and vice versa.

The cam moves at half crankshaft speed, in other words the cam turns 180 degrees for every one revolution of the crank, or one cam revolution for every two crank revolutions.  The ignition on these bikes is of wasted spark design, in other words the coils fire spark plugs in pairs, the pairs being 1/4 and 2/3.

The basics of a four stroke engine are for every piston stroke the crank turns through 180 degrees, there are believe it or not 4 strokes for every cycle.  On the first stroke, the piston moves down with the intake valve open, this is the intake stroke.  Next the intake valve closes and the piston moves up on the compression stroke.  The spark plug then fires and the intake charge burns and pushes the piston down, this is the power stroke.  The exhaust valve then opens and the piston moves up on the exhaust stroke.  When the piston reaches the top the exhaust valve closes, the intake valve opens and it starts all over again.  Now they don't open and close exactly at TDC and BDC (bottom dead centre), there is lead in and out as well as overlap, but that is of little consequence in this case.

So in short, the cam makes no difference which way round it is, forwards or rearward, as long as it is timed on the 1/4 T mark on the crank, this is crucial.  With the cam in either forward or rearward, you still have a piston at the top on compression and spark on that cylinder so it will still run. 

[Vinhead1957]

What is also critical. Nobody has mentioned, the advance unit has a possibility of being mounted incorrectly. Evident by some guys here having their blue and yellow wires crossed at the coils. Verify the advance unit is installed on the crank properly.

[dave500]

not mounted on the crank correctly as such as it only goes on one way,but if you take it apart the little barrel cam must go back on the correct way or the ignition will end up 180 out,they have a tiny not real clear index mark.

I put the photo for all the five year olds.

[calj737]

I put the photo for all the five year olds.

Thank goodness too, I was confused without it-

[Vinhead1957]

I like that photo! Add fifty to that 5

[Jimsun]

Thanks vin and dave. The pic youve posted dave are two different type of barrel correct? But they both have the dot that shout allign to the tec hole thats on the same side as 2*3

[trueblue]

Thanks for explaining it like im five!!! I understand it now thank you

I wasn't explaining it like you were five.  I was explaining it like I would to someone who has minimal experience with engines.  I tend to explain stuff like I would to someone who has a clue, which from your previous comments was something you appeared to lack, because after numerous posts you still weren't understanding it.  My intention was not to be condescending, only trying to be informative and help you get your bike going.  Something which I may think twice about next time if I'm going to get attitude for my efforts.

[Jimsun]

Please dont take it the wrong way. I appreciate the detailed explanation.  Thank you again

Thanks for explaining it like im five!!! I understand it now thank you

I wasn't explaining it like you were five.  I was explaining it like I would to someone who has minimal experience with engines.  I tend to explain stuff like I would to someone who has a clue, which from your previous comments was something you appeared to lack, because after numerous posts you still weren't understanding it.  My intention was not to be condescending, only trying to be informative and help you get your bike going.  Something which I may think twice about next time if I'm going to get attitude for my efforts.

[trueblue]

Please dont take it the wrong way. I appreciate the detailed explanation.  Thank you again

Thanks for explaining it like im five!!! I understand it now thank you

I wasn't explaining it like you were five.  I was explaining it like I would to someone who has minimal experience with engines.  I tend to explain stuff like I would to someone who has a clue, which from your previous comments was something you appeared to lack, because after numerous posts you still weren't understanding it.  My intention was not to be condescending, only trying to be informative and help you get your bike going.  Something which I may think twice about next time if I'm going to get attitude for my efforts.

It's not a problem, just be careful how you word things on the forum.  Text doesn't convey emotion very well, and it is very easy to take things the wrong way. 

[dave500]

Thanks vin and dave. The pic youve posted dave are two different type of barrel correct? But they both have the dot that shout allign to the tec hole thats on the same side as 2*3

yeah the advancer units aren't always exactly the same,just take note how hard the index mark is to spot if its dirty or rusty?if its moving free don't take it apart.