Author Topic: After cam swap, won't start | Block off pics  (Read 20712 times)

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Offline stereosilence

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After cam swap, won't start | Block off pics
« on: October 02, 2012, 03:58:27 pm »
Finally got the 650 cam swapped in and the valves adjusted and everything put back together. Now it won't start. When I hold the electric starter the best it will do is cough some and a bit of white smoke will come out (which, if I remember correctly, denotes oil). I tried with the choke on and off.

I got it started yesterday for just a bit, but it was difficult then too. I also tried kick starting it, but no luck. Any words of wisdom?
« Last Edit: October 16, 2012, 01:15:21 pm by stereosilence »

Offline Dimitri13

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Re: After cam swap, won't start
« Reply #1 on: October 02, 2012, 04:11:56 pm »
Any jetting changes?

Offline stereosilence

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Re: After cam swap, won't start
« Reply #2 on: October 02, 2012, 04:18:44 pm »
Nope.

Offline matt mattison

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Re: After cam swap, won't start
« Reply #3 on: October 02, 2012, 04:37:56 pm »
Did you static time the engine before trying to fire it up?
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Offline Gordon

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Re: After cam swap, won't start
« Reply #4 on: October 02, 2012, 04:56:29 pm »
Did you reconnect the plug wires correctly?

Offline stereosilence

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Re: After cam swap, won't start
« Reply #5 on: October 02, 2012, 04:58:28 pm »
I'm not sure what static timing is. I aligned the new camshaft correctly with the TF-14 mark.

As I understand it, plugs 1/4 are interchangeable and 2/3 are interchangeable, correct? There is no way that I could have plug 4 installed to plug 1 and it wouldn't work is there?

Offline steam-powered man

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Re: After cam swap, won't start
« Reply #6 on: October 02, 2012, 05:03:12 pm »
cam might be 180 out, try swapping the blue/yellow points wires.  btdt
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Offline dave500

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Re: After cam swap, won't start
« Reply #7 on: October 02, 2012, 06:12:09 pm »
the cam CANNOT be 180 out.

Offline stereosilence

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Re: After cam swap, won't start
« Reply #8 on: October 02, 2012, 06:21:08 pm »
Checking the timing is probably a good place to start. I'll get on that and get back to ya'll. Any other suggestions are welcome. I actually ran it for a few seconds yesterday, so I don't know what happened. I cut it off and installed the 650 tachometer and drive and today it won't start.

Offline MCRider

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Re: After cam swap, won't start
« Reply #9 on: October 02, 2012, 06:35:25 pm »
cam might be 180 out, try swapping the blue/yellow points wires.  btdt
In deference to the "can't be 180 out" idea, I can't think it thru. I do know that there have been 3 instances of people swapping cams, suffering a no start condition, swap the point wires, and it starts. IF that's not 180deg out, I don't know.

Weren't you one of those victims SPM?

Proof is in the punch, swap the wires, can't hurt.
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Offline dave500

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Re: After cam swap, won't start
« Reply #10 on: October 02, 2012, 08:26:19 pm »
it was running with the cam swapped and now its not,unless the wire swapping elves are at it again?

Offline steam-powered man

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Re: After cam swap, won't start
« Reply #11 on: October 02, 2012, 08:48:51 pm »
yup, that was me.  set the cam with slot pointing down instead of up.  cough, boom, sputter, fart, and repeat.  swapped points wires and zoom!   wasn't that 180 out?  sometimes i think i live in an alternate universe where up is actually 270 degrees from down.   :o   
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Offline dave500

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Re: After cam swap, won't start
« Reply #12 on: October 02, 2012, 09:14:29 pm »
the slot should be horizontal,you must have had the crank misaligned aswell?if you have the cam a few teeth out you will bend valves.

Offline 750resurrection

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Re: After cam swap, won't start
« Reply #13 on: October 02, 2012, 09:18:57 pm »
Use some starting fluid, especially if you have pods.

Offline phil71

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Re: After cam swap, won't start
« Reply #14 on: October 02, 2012, 09:33:17 pm »
Starting fluid !? 

Offline dave500

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Re: After cam swap, won't start
« Reply #15 on: October 02, 2012, 09:38:06 pm »
yeah starting fluid is beer,then you run on bourbon!

Offline steam-powered man

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Re: After cam swap, won't start
« Reply #16 on: October 03, 2012, 05:15:59 am »
actually, on this particular cb750k there were 2 "index lines" aligned horizontally with the cam holder and one "slot" to be pointing up.  got some good advice and saved me from yanking the engine.   ;)
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Offline stereosilence

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Re: After cam swap, won't start
« Reply #17 on: October 03, 2012, 07:41:28 am »
Well, I aligned the notch horizontally according to the manual. I know this cause I did it wrong the first time and to go back and redo it.  ::)

I won't have a chance to work on it til tomorrow. I'll try swapping the wires and checking the timing.

Offline dave500

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Re: After cam swap, won't start
« Reply #18 on: October 03, 2012, 12:28:20 pm »
its a 550 not a 750 steam man.

Offline steam-powered man

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Re: After cam swap, won't start
« Reply #19 on: October 03, 2012, 05:40:29 pm »
"its a 550 not a 750"

oops / eek! 
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Offline stereosilence

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Re: After cam swap, won't start
« Reply #20 on: October 04, 2012, 05:20:32 pm »
Got home and was going to check the timing, tried to turn it over and it made a terrible noise. On the other hand, the ignition timing was at least close, so I don't need to swap wires or anything. I posted a video of the sound. If you have any ideas, let me know. I can't tell if it is metal on metal scraping or a rubber-squealing noise. I guess I'll take it apart *again* a piece at a time and see if I can find the problem.

Engine Noise

Offline MCRider

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Re: After cam swap, won't start | Engine Noise Vid!
« Reply #21 on: October 04, 2012, 05:33:34 pm »
Please don't use that nut for turning the engine, they snap regularly.
Curious. That's what its for. Nice if one can remove the spark plugs, but even so... that's what that nut is for. Treat it right, it won't snap.

What do you use?
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Offline crazypj

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Re: After cam swap, won't start | Engine Noise Vid!
« Reply #22 on: October 04, 2012, 05:35:06 pm »
cam might be 180 out, try swapping the blue/yellow points wires.  btdt
In deference to the "can't be 180 out" idea, I can't think it thru. I do know that there have been 3 instances of people swapping cams, suffering a no start condition, swap the point wires, and it starts. IF that's not 180deg out, I don't know.

Weren't you one of those victims SPM?

Proof is in the punch, swap the wires, can't hurt.

 That can only work if points cam is mounted on camshaft.
This isn't so can't be 180 out
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Offline Tews19

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Re: After cam swap, won't start | Engine Noise Vid!
« Reply #23 on: October 04, 2012, 05:53:17 pm »
Please don't use that nut for turning the engine, they snap regularly.
Curious. That's what its for. Nice if one can remove the spark plugs, but even so... that's what that nut is for. Treat it right, it won't snap.

What do you use?


Curious, i thought that is what it was for too... Thats what I've used...

Did you stick a cat in the cylinder????????????? Sounds like one is getting kicked
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Offline MCRider

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Re: After cam swap, won't start | Engine Noise Vid!
« Reply #24 on: October 04, 2012, 05:59:38 pm »
Sorry that doesn't sound good. Maybe you've answered this, but are they new pistons and rings? Were the rings end gaps checked.

Be sure to document your cam timing for posterity. Curious.
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