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Discussion Starter #1
So I replaced my base gasket and cylinder head gasket along with various orings. hooked everything back up and now the motor turns and sound like it is trying to start but the motor stops at a certain point and will not turn over. Then all of the sudden gas came out of the carb hose. The motor will turn back by hand but then it does the same thing over.



What could be cause?



Thanks for everyone’s input.
 

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Are you saying the engine literally stops after a few cranks? or the starter goes slower and slower after each attempt?. Gas out of the carb hose....Bowl overflow/drain at the bottom?....stuck float?.
 

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Sounds like your timing chain is not in time! Did you check to make sure you put it in the right position? Im guessing your hitting a valve because its opening when its not supposed to. Thats my guess anyway.
 

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Discussion Starter #4
litterly stops and crank kick start either. When I pulled the base the piston slipped out of the cylinder. There is an arrow on the top of piston. Which way daoes it point. rear or front
 

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Double check your cam timing, including making sure it's on the compression stroke when the marks line up. Don't force it if it won't turn over a complete revolution, as Smalls pointed out you could bend a valve if you do so. Once or twice when I've had the carburetor off, gas would run out of the overflow as soon as I turned the petcock on. Apparently the float got stuck when I laid the carburetor on it's side; tapping the float bowl with a wrench jarred the float loose and solved the problem. On page 140 (Chapter 4, page 60) of the main manual it specifies the arrow on the piston points to the front of the engine.
 

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Discussion Starter #6
It is possible that I need to adjust timing I was getting excited since it has been three weeks since I last rode it and been stuck in an ACless cage. I will try tomorrow to re time it.







Thanks again everyone.
 

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You have to be diligent when installing the chain. Line up the marks on both the cam and crank. Then after installing the chain, carefully turn the engine through several revolutions and then back to the marks again to make sure both line up properly before buttoning everything up.



If you got the cam timing off like it sounds like, you'll be fortunate if you didn't bend a valve.
 

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Discussion Starter #8
I had lined up the tick mark on the cam with the T on the rotor when I re-installed. Could it have been off 180*.
 

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No. A camshaft cannot be 180 degrees out. Since its a two to one ratio of cam to crank revolutions, every time the crank turns one turn (mark lines up), the cam turns half a turn. Therefore even if you timed the cam 180 degrees from where it was, its still accurate because when you rotate the crank a full turn, the marks will line up.
 

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Discussion Starter #10
Well the mark lines up on both and valve clearance was right....? Just trying to start it by electric after 10 seconds it seizes up. Then I could hand crank it backwards and it would release then I tried kicking it to start and it took about three kicks before it stopped and I was still able to hand turn it.





So I should take the cam off and turn it one more full revolution till T lines up again and then try it?



Sorry for all the questions just trying to get it right and clarified.





Thanks



PS When I disconnected the clutch cable the arm for the clutch swung back towards the rear of the bike. When I reinstalled the clutch cable I had to push the bike forward to be able to move it by hand
 

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I was brief because I typed that last response on my phone.



Lets get the basics down first.



All four stroke engine are designed so that the crankshaft is timed on a 2:1 ratio with the camshaft. That is, every time the crankshaft spins one turn, the cam spins exactly half a turn. So, it takes two turns on the crank to make one turn of the cam.



Now, my earlier explanation of it being impossible for the cam to be 180 degrees out of time is as follows.



If you line up the cam and crank marks perfectly as the manual states, and turn the crank one turn, you'll notice the cam is now exactly 1/2 turn away from the marks. If you turn the crank another full turn, the marks will again be aligned as you had put them together.



Therefore, it is impossible to install a camshaft 180 degrees out. Simply turn the crank one turn and now the marks are aligned.



1. First assure that you can line up the crank mark and the cam mark when you turn the engine. Remember, if the cam shows 180 out, just turn the crank another turn and they should align properly.



2) If the marks are good you need to dig deeper. I personally wouldn't turn it anymore than I had to and would disassemble the engine to find the cause. If you have an issue with the piston or whatever, further attempting to turn the engine through by force is going to worsen any damage that might be taking place.



3) Are you damn sure you didn't leave a rag or bolt or socket or something in the cylinder on top of the piston when you reassembled? You might take the plug out and peer down into the plug hole to make sure.
 

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It's the other way around. The crank turns twice for every one turn of the cam. The crank has half as many teeth as the cam does.



Look at it this way, each valve (cam operated) only operates every other crankshaft revolution (piston cycle)



On one piston tdc, both valves are closed, on the next piston tdc, the valves are open.
 

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Discussion Starter #14
That is what made me think that it could be 180*/half way out that I had the cam turned upside down on one of the revolutions



Thanks again I will give an update late on.
 

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Discussion Starter #15
That is what made me think that it could be 180*/half way out that I had the cam turned upside down on one of the revolutions



Thanks again I will give an update late on.
 

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Ayers Garage has offered some great insight and advice.



Definitely don't turn it over with the electric or kick starter anymore until you figure out the problem. Use a socket on the crank bolt so you have more control and less leverage.



With the transmission in neutral and the spark plug removed does the engine turn freely, then just stop? If so it could be a bent or stuck valve (not likely since you verified timing and valve clearances were correct) or something that fell into the engine. Did you account for all the parts when reassembling? If one of the locating dowels fell into the engine and you didn't notice it could cause the engine to lock up.



In any case, I agree with Ayers Garage. Other than cam timing I can't think of anything that would cause the engine to lock up that can be fixed without disassembling the engine again. It'll cost you a little bit for parts, but sometimes that's the price we pay for learning. You'll likely still be into it way less money than if you had paid someone to do your base gasket, and you'll have gained the knowledge, experience, and confidence to continue working on your bike.



Last of all, don't despair. If you can maintain a positive attitude and have some patience and persistence this can be a good learning experience and you will have your bike running again in no time.



PS If the cam timing is indeed correct I'm betting something fell into the engine unnoticed.
 

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Discussion Starter #17
So for a recap. Took the cylinder head off last night and the valve gaps some how were off quite a bit. Readjusted them to specs and also found that when I re-installed the cam sprocket and chain, the chain was cockeyed on the crank sprockets which was causing the chain to slip and when that happened the piston would hit the partially open valves. Piston turned like butter after.



When I went to try and start it I had only put about a quart of gas in the tank which had all drained out because of the stuck float. Now just need to get some gas and get her cranking.





Thanks for all the advise and knowledge.



You guys rock
 

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That supports what I said earlier. When you reassemble any engine, turn it through by hand a few times and then bring the marks up again and check that they still line up. That way you can catch stuff like that early before you button the engine all the way up.
 

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Discussion Starter #20
So basically the chain wasnt completely on the crank sprocket? And when the engine was turned it came off?




They chain never fully came off the crank sprocket but it would turn to a point stop. Like it was 3/4 of the way on and I could turn it about 1.5 revolution then it would stop. So when I checked the first time by hand it went around 1 revolution fine with both ticks lining up. So I think it was a combination of the chain partially off and it needing a valve adjust.
 
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