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Author Topic: CB350F cam 180 out ?  (Read 2107 times)

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Offline Blackhole

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CB350F cam 180 out ?
« on: April 07, 2012, 04:02:44 PM »
I have my head back together and was reading how to set the timing during reassembly.  Can you put the cam in 180 out or is there no wrong way as long as the lines on the cam sprocket and and timing mark by my points are in the correct spots.  It just seems that one way is going to be 180 out...and knowing my luck that is how mine will be.  It might seem like a simple question but I really don't want to take it apart again.  Thanks for all the help with this bike.
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Offline kslrr

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Re: CB350F cam 180 out ?
« Reply #1 on: April 07, 2012, 05:11:13 PM »
As long as you didn't remove the cam sprocket from the cam, you should be ok, and even then I seem to remember that there is only one way to bolt the sprocket to the cam.
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Offline MCRider

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Re: CB350F cam 180 out ?
« Reply #2 on: April 07, 2012, 06:28:29 PM »
On a 750, it can be 180 out. There was a recent post here from a guy that did that, and buttoned the motor all up and tried to start it and it wouldn't. Much bigger deal on a 750 as the engine must come out of the frame.

I told him to reverse the point wires. He did and came back on the thread praising me as the genius i am. it ran fine with the points reversed.

I'll get the thread if you need convincing, if it will help. That is, if a 350 cam can be assembled 180 out.
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Offline Blackhole

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Re: CB350F cam 180 out ?
« Reply #3 on: April 07, 2012, 06:42:09 PM »
I just went out and looked again and the cam can be installed with the lobes for number one either up or down.  I am now not sure that it matters as number three piston is all the way down and that coil fires both one and three.  I will post back what I find.  I am going to install the cam lobes up.
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Offline MCRider

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Re: CB350F cam 180 out ?
« Reply #4 on: April 07, 2012, 08:28:21 PM »
The coils are 1-4 and 2-3.  Be sure.

On the end of the cam, at least on a 750 is an index mark. I think its cam lobes down on cyl #1, ignition on the T for 1-4.  On a 750.  Your manual should have all the clues.

AS I said, if you do it wrong just switch the point wires and you'll be running.
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Offline trueblue

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Re: CB350F cam 180 out ?
« Reply #5 on: April 07, 2012, 08:42:34 PM »
Quote from: MCRider on April 07, 2012, 06:28:29 PM
On a 750, it can be 180 out. There was a recent post here from a guy that did that, and buttoned the motor all up and tried to start it and it wouldn't. Much bigger deal on a 750 as the engine must come out of the frame.

I told him to reverse the point wires. He did and came back on the thread praising me as the genius i am. it ran fine with the points reversed.

I'll get the thread if you need convincing, if it will help. That is, if a 350 cam can be assembled 180 out.
Lately this topic comes up at quite a bit, on any 4 stroke engine there is no way a cam can be installed 180 out because for every turn of the crank the cam turns 180 degrees, so if you think the cam is out 180 simply turn the crank one full turn and it will be where it is supposed to be.  If the other guy had to swap his point wires to make it go, it is very simple he had them back to front from the get go.
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Offline heffay

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Re: CB350F cam 180 out ?
« Reply #6 on: April 08, 2012, 01:54:13 AM »
Does it try to start every so often then gives a really loud backfire?  Tell tale sign you're out 180... Flip your coil wires, should start right up.
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Offline faux fiddy

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Re: CB350F cam 180 out ?
« Reply #7 on: April 08, 2012, 02:05:01 AM »
Quote from: heffay on April 08, 2012, 01:54:13 AM
Does it try to start every so often then gives a really loud backfire?  Tell tale sign you're out 180... Flip your coil wires, should start right up.

It seemed to me that it was nearly impossible to go 180 out when putting it back in if marks are level.

Does it matter at all?  This is a lost spark system, no?  It gets a spark at 180 out anyway?
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Offline trueblue

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Re: CB350F cam 180 out ?
« Reply #8 on: April 08, 2012, 02:08:09 AM »
Quote from: fiddy of industry on April 08, 2012, 02:05:01 AM
Quote from: heffay on April 08, 2012, 01:54:13 AM
Does it try to start every so often then gives a really loud backfire?  Tell tale sign you're out 180... Flip your coil wires, should start right up.

It seemed to me that it was nearly impossible to go 180 out when putting it back in if marks are level.

Does it matter at all?  This is a lost spark system, no?  It gets a spark at 180 out anyway?
Finally someone is on the right track
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Offline heffay

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Re: CB350F cam 180 out ?
« Reply #9 on: April 08, 2012, 02:12:58 AM »
I've yet to install my cam wrong, I dunno  ;D ;)
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Online Bodi

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Re: CB350F cam 180 out ?
« Reply #10 on: April 08, 2012, 05:06:09 AM »
"I've yet to install my cam wrong, I dunno"

That's because there is no wrong.

Take all the care in the world to install one the "right way", take copious notes and dozens of photographs on disassembly. Match everything when you reassemble, so you are 100% certain the cam is in "the same way".

Now turn the crank one full time.

Since it was assembled perfectly, it must still be perfect.

The cam will now be "180 degrees out". The way you spent lots of effort avoiding.

There is no difference. If you have to rewire the coils, you had the coils wired wrong. The cam orientation is not to blame. When you have the crank at 1-4T (corrected, too much beer) and the cam mark correct - the cam timing is set properly. You can flip the cam 180 degrees or turn the crank 360 degrees and it does not change anything.
« Last Edit: April 08, 2012, 06:19:57 PM by Bodi »
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Offline MCRider

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Re: CB350F cam 180 out ?
« Reply #11 on: April 08, 2012, 05:56:23 AM »
Crank at 1-3T?
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Offline heffay

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Re: CB350F cam 180 out ?
« Reply #12 on: April 08, 2012, 09:13:36 AM »
And yet again, even with a wink and a smile, my sarcasm is lost on some.
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Offline Gordon

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Re: CB350F cam 180 out ?
« Reply #13 on: April 08, 2012, 11:50:06 AM »
Quote from: heffay on April 08, 2012, 09:13:36 AM
And yet again, even with a wink and a smile, my sarcasm is lost on some.

It's not that the sarcasm is lost.  We just think you're flirting with us, and it's really kind of awkward. :-[
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Offline Blackhole

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Re: CB350F cam 180 out ?
« Reply #14 on: April 11, 2012, 05:59:53 PM »
It went in with ease and the bike fired right up after adjusting the valves.  I just got back from a quick ride and it was a blast !  I have not had a bike for over twenty years (age of my oldest child) and this is going to be a great summer.
 Thanks for all the help.
Blackhole
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