I think my new Samger motor has a defect...

Rusty_Nail

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Oct 11, 2019
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So I got the motor all hooked up today and got it started for the first time. I noticed that the four bolts on top of the head were a bit loose cause it was leaking some smoke from around the gasket under the top of the head. In trying to tighten them down just enough so it won't have a head leak, one of the bolts seems like it won't tighten. It just keeps turning and turning. What can I do to fix this? motor only has like 5 mins run time on it.
 
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Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
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I'm not sure the bolts were actually loose... These engines have what looks like a 'air gap' between the head & cylinder that people always mistake for a problem. (The smoke is also common on a brand new engine).
Another thing that makes me believe this is that if the head bolts were actually loose?, the engine probably wouldn't start

It sounds like you over torqued the bolts & stripped one out. :(

You need to follow all the advice given above to repair it & re-torque the head bolts to 12- ft/lbs
 
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Rusty_Nail

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I’m almost sure it’s the threads in the case. The nut was on so tight it unscrewed the long bolt with it. So when I tried to put it back in it would just keep turning and wouldn’t get tight. Could I still run it normally like that?
 
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Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
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I’m almost sure it’s the threads in the case. The nut was on so tight it unscrewed the long bolt with it. So when I tried to put it back in it would just keep turning and wouldn’t get tight. Could I still run it normally like that?

You might still be able to save it!!!

First... Sand the head surface flat again (as mentioned above), & buy a new head gasket.

Next... remove the nut & thread the stud back into the case as far as it will go... Hopefully the stud will find some good threads deep down in the case

Then re-torque all the nuts to only 10 ft/lbs this time using only the flat washers under the nuts



Hopefully this will work.
 
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Rusty_Nail

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I have a new copper gasket. And I’ll try sanding the head too. Problem is the nut is torqued down so tight I can’t get it off the long stud. Came that way. Even tried using vise grips to get it off but it won’t come off.
 
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Greg58

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I’m sure Norm will agree, the acorn nuts are not what you need to use to get accurate torque, they often bottom out before you reach the torque needed to seal the head. That’s what happened to yours.
 
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Rusty_Nail

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UPDATE: So I finally got around to pulling the head/cylinder to check the hole in the casing. Good news is from what I could see the threads didn't appear to be stripped at all. Was easily able to thread it in and hand tighten it and so far it didn't seem to slip at all. I noticed the threads on the top of the stud where the nut goes had a small gouge in it on two of the four studs. So I ordered four new studs and they are supposed to be here tomorrow. I would also like to know what the proper torque specs are for the stud that goes into the hole so I don't risk stripping it out.
 

Greg58

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12 foot pounds, run the studs down as far as you can by hand and snug them. then add the nuts and run them down till each touches the head then torque in a x pattern. I use two nuts jammed together to snug the stud into the case.
 

Rusty_Nail

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Ok so would you say as a rule of thumb barely past hand tightened for the bottom of the stud itself?
 

Greg58

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I take two regular nuts and tighten them against each other then turn the stud down till it’s snug, then unlock the two nuts. That usually keeps the stud from backing out when you loosen the head nuts