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Discussion Starter #1
Hi all, new to this forum.
Short story: '71 cb450 motor and only the necessities to start, kick started fine the first time, and it idled fine. Next, tried the starter motor, didn't work, gas shot from air jet. Kick start is now verrryyy difficult to turn, and it doesn't spring back up anymore. Pistons move up and down with no problem.
Help?

Long story:
I recently picked up a cb450 motor (just motor and carbs), and then some. I plan on using it for a country yard go kart - so budget is low. I was told it had been sitting around for a little under 10 years. Anyhow, I went the cheap route and got universal coils and condensers to get the engine to start. I greased up the cam lobes and put in fresh oil, cleaned the carbs and such. Hooked up the coils and condenser, etc... I mocked up a wood frame to hold the engine while i tried to kick start it.
A few kicks later it started and idled perfectly fine, but without headers, i turned it off after a minute.
After i was sure it could idle, I wanted to make sure i could start it with the starter motor since I didn't want to deal with kick starting it on a go kart chassis.
I hooked up power to the starter motor, nothing happened just slight whirring. It was a very old battery that I let charge earlier that morning. I figured the battery wasn't fully charged or giving out enough current. I tried to jump start the motor with my car; this time, the starter turned the engine over a couple times and the carbs SHOT gas out of the air jet. I let the starter cool for a few minutes, tried again, and same result. The starter motor is hooked up properly, and the starter clutch rotates freely one way, and restricted the opposite way.
So i go to kick start it, and the kickstart will not move as easily as before, nor will it spring back into place. Also, one of the carbs is spewing gas out of the overflow, so I'll have to check the needle and such.

I've tried to turn the crankshaft via the flywheel bolt, and it turns fine clockwise(? don't remember). The crankshaft will only turn a 180 degrees before it will get really difficult when i turn it counter-clockwise.

Whew! that's a lot to read. any help? Thanks.
 

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Well, it definitely sounds like you have a sticking needle in your one carb.

One thing I would try is pulling both spark plugs out and trying both starters like that. See if the symptoms improve. I think there's a slim possibility you're experiencing a hydraulic lock in the one cylinder. Maybe, or maybe not. BTW, when you crank the engine over, make sure to stand out of the line of fire of the plugs, otherwise you'll get a gasoline shower and have to work the rest of the day like that. Don't ask me how I know.

Otherwise, the kickstarter mechanism and starter clutch are pretty easy to access under the side covers, so pop them off quick and have a look. Maybe something is gummed up from sitting. I've had that happen on one of my 450's.
 

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Discussion Starter #3
I'm not sure a hydraulic lock is possible since it was already idling fine, the electric start screwed it all up.
On the other hand, everything that is covered by the crankcase covers are totally clean. The starter clutch rotates fine one way so i'm not sure its gummed up or sticky. Thanks though
 

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If I read your post correctly, it idled fine and then you shut it off and did a couple things like hook up your jumper cables etc. Granted it would have to be REALLY puking gas down the throat. Either way, pull the plugs and see if it makes a difference not having to fight the compression to turn the engine over. Not having seen it, that's the best guess I have at the moment.

If I remember correctly, you have a ball type starter clutch, where the balls will clamp down one direction, but slip the other. Maybe something is just sticky down there. Hit it with some penetrating oil and see if it makes a difference.
 

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Discussion Starter #5
I've pulled the plugs since yesterday, and rotated via the flywheel, kickstarter, and starter motor. Rotates fine with plugs out and in, of course it's harder to rotate with the plugs in.

The carb problem is gone after disassembling and spraying some penetrating oil at the float needle. I even went ahead and adjusted the float.

My last guess is that the starter motor is on its last leg so I guess I'll have to get it rebuilt or something.

My main, new, problem is the kickstarter not retracting to its stowaway position. I've checked the return spring under the cover-still engaged. I do notice, though, that the kickstart has a spring back force when I really try to kick it down with more force than before. (bad idea... i know, just sorta desperate)
 
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