Author Topic: Motor really hard to kick over  (Read 1311 times)

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Offline B.O.X.N.I.F.E.

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Motor really hard to kick over
« on: April 17, 2011, 07:32:22 PM »
1973 CB450

Did a tune up from scratch on a bike with unknown history. During tune up it would kick over and turn easily with a wrench on the end of the crank. Got everything assembled and rolled the bike outside. It is extremely difficult to kick over and the starter seems to be laboring when turning the motor over. I'd describe the motor as feeling 'tight'. The bike will not start, has fuel and spark.

Any suggestions? Somewhere between a basic tune up and first start is where things went wrong.
« Last Edit: April 18, 2011, 01:43:50 PM by B.O.X.N.I.F.E. »
1974 CB550

32 days and 5,536 miles on a CB550...

http://kerncountykid.blogspot.com/

and a couple years later, 38 days and 9,102 miles...

Forever West

... and all of it in a 4 mintue video

<a href="Not a valid vimeo URL">WWYY?[/url]

Offline B.O.X.N.I.F.E.

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Re: Motor really hard to kick over
« Reply #1 on: April 18, 2011, 12:41:16 AM »
bump for the overnight crew, this thing is killing me. Plugs out, making compression, exhaust off, clutch cover off, cams turning, left side cover off... I see nothing. It's a monster to turn over and the resistance is even through all 360 degrees of rotation. Nothing clunky sounding.
1974 CB550

32 days and 5,536 miles on a CB550...

http://kerncountykid.blogspot.com/

and a couple years later, 38 days and 9,102 miles...

Forever West

... and all of it in a 4 mintue video

<a href="Not a valid vimeo URL">WWYY?[/url]

Offline B.O.X.N.I.F.E.

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Re: Motor really hard to kick over
« Reply #2 on: April 18, 2011, 01:44:14 PM »
Anyone else think it could be a bent intake valve? Method for checking with the head on?
1974 CB550

32 days and 5,536 miles on a CB550...

http://kerncountykid.blogspot.com/

and a couple years later, 38 days and 9,102 miles...

Forever West

... and all of it in a 4 mintue video

<a href="Not a valid vimeo URL">WWYY?[/url]

Offline MoMo

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Re: Motor really hard to kick over
« Reply #3 on: April 18, 2011, 07:06:42 PM »
You may want to check the starter motor clutch as they have been known to come apart...Larry

Offline kirkn

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Re: Motor really hard to kick over
« Reply #4 on: April 19, 2011, 06:34:47 AM »
Hmmm..... 

My own method is to first ask - what did I screw up?  I mean, it's possible that some other component decided to fail right now, but usually, it's something I did.  Especially as you describe - it was working fine DURING the task, but once you got it back together and rolled it outside, it DIDN'T. 

I don't think it'd be a bent valve because that would be hard to turn over as the valve was opened, but then the cam would just turn out from under the valve and resistance would be gone and the valve would hang open.

What else did you mess with?  Cam chain tensioner?  Points plate on end of cam?  When you describe it as "wrench on end of crank" how were you doing that?  Thru what cover?  And did that cover not go back on right, etc?

Sorry I'm not more help - I don't know much about the 450's, but just generic troubleshooting.  Good luck with it.

Kirk

Offline B.O.X.N.I.F.E.

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Re: Motor really hard to kick over
« Reply #5 on: May 02, 2011, 11:13:02 PM »
Turned out to be an extra shim on the exhaust cam, coupled with the cam timing indexes being a full tooth off. Took awhile to figure all that out.

and in the end it one carb wouldn't work because the kit came with float valves of differing shapes. Lots of weird little problems on this one :/
1974 CB550

32 days and 5,536 miles on a CB550...

http://kerncountykid.blogspot.com/

and a couple years later, 38 days and 9,102 miles...

Forever West

... and all of it in a 4 mintue video

<a href="Not a valid vimeo URL">WWYY?[/url]