I've just rebuilt top of me engine and now it won't turn over. Starter motor spins but when I have it in the engine, it spins for a slight second then stops, seems there is something stopping starter clutch spinning more than a couple degrees. I've tried turning engine over by hand on right hand side of engine but it feels like there is a lot of resistance and is tight. What could cause this?


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Just had a look at cams, at tdc, left is on 3, on the right, it's on 2 and is facing straight up, there is 18 pins between both of them, but after a turn, the chain gets so tight again


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Bummer!  You can do singe detective work by removing the spark plugs, carbs and exhaust and watching the sequence of the pistons and valves.

Did you leave any tools or things inside the engine compartment?  Are you using extra long spark plugs? (Seems like those would just shatter tho)

  Are the valve shims still in place? (I've heard that a missing shim can lock and engine)  link

Also while you have the cam cover off look to see if any of the buckets are stuck down. A user on this forum had that happen to him.

Anyhow, don't be too worried about it, your motor will probably be fine with only a little more work.  Go slow though, try to diagnose the problem 100% before you destroy the evidence.  If you just start yanking things apart you can cause more headaches for yourself.

Thanks mate, I'll have a check when I get some more time, one thing after another but complete build up from scratch so not giving in yet haha


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When you say "tdc" do you mean that the right piston is at tdc?  setting timing

Quote from: scotty110788 on February 27, 2016, 09:33:50 AM
Just had a look at cams, at tdc, left is on 3, on the right, it's on 2 and is facing straight up, there is 18 pins between both of them, but after a turn, the chain gets so tight again


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Yea, top dead centre, so right is all way up


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How good/charged is your battery?

Brand new, filled and slow charged overnight


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All connections to battery/frame correct and firm/tight?

Try removing the spark plugs and see if you can rotate the engine easier.

Perhaps the normal compression of the engine is what is stopping you from turn the engine over by hand. There is normally a fair bit of resistance to turning the engine over.


From your pictures the intake cam cap is not bolted down.  This photo was taken during the assembly and has since been secured, correct?

All connections look spot on, and yea, photos wer took during assembly, ive trying jumping it with leads to make sure it's not battery, starter motor is off to shop later on to see if it's that, thanks for all help


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Right, starter motor is ok, gonna take sump off and see if I can see anything that I may off missed in engine, check clutch plates incase anything is jamming them, and if all else fails, take top end off again for another look inside engine


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https://vimeo.com/158367035https://vimeo.com/158367392

One spinning by hand without starter motor in, the other trying with starter motor in


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Is the cam chain tensioner functioning as it should?

Yea I'm positive it is


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I don't think the starter motor is supposed to jump around like that

Chain was kinked at the bottom so putting back together again and hopefully that was the issue, was turning freely though so don't get how chain slipped and got jammed 😩


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Wow, I would have never guessed. Good work figuring it out. 

Sorted it again, it keeps jamming every time I put the chain tensioner back in so is there a possibility it could be that


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