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Head Leak


Discussion at Motorized Bicycle Engine Kit Forum in the Motorized Bicycle General Discussion forum. I've just put together my first motorized bike & from the word go the head is leaking to one ...
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Old 07-26-2008, 04:02 AM
Senior Motorized Bicycle Builder
 
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Default Head Leak

I've just put together my first motorized bike & from the word go the head is leaking to one side only (front right), I have followed instructions to a tee 12ft/lbs head bolt tension, but it seems not to seal up, I have taken the head off & gasket is not blown, cant stop the leaking, should I put a dab of blue locktite on head bolts as well, but I cant see how this will rectify the problem, any suggestions would be greatly appreciated
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Old 07-26-2008, 05:34 AM
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Default Re: Head Leak

Torque the head bolts down in an x pattern. Run the engine, let it get hot. After it cools down retorque in an x pattern again. They will be loose. The next couple of times you ride retorque the the bolts. You might spray some aluminmum paint on both sides of the head gasket. I don't think I would use loctite on the head bolts. Hope this helps...............................
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Old 07-26-2008, 10:27 AM
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Default Re: Head Leak

Thanks for the tip, I will give it a go, the distributor on his web page states to use locktite, but I will take your advice and do as you say, and will see if this stops the leak

Cheers
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Old 07-26-2008, 10:49 AM
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Default Re: Head Leak

Good luck with it...

Tightening down anything like a head or even the valve cover on a motor - always go crosswise as has been said - doing anything different will likely cause warping of the head - specially on alloy motors..

Jemma xx
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Old 07-26-2008, 11:02 AM
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Default Re: Head Leak

X is the word, when its daylight I will ride around the block a few times & get her hot, once its cooled I will do the X thing & take her out for a flang, and do the same over again.

Hopefully this will rectify the issue, I have noticed the studs are very poor quality so I might try to replace them with better ones from somewhere.
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Old 07-26-2008, 11:35 AM
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Default Re: Head Leak

All good advice.

If the Al paint doesn't work, you may need to lap the head a bit on some wet dry sandpaper (wet w/water and dish soap) - see Norman's thread. Then use a NEW gasket and the Al paint trick.
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Old 07-26-2008, 04:53 PM
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Default Re: Head Leak

I'm having problems with the cylinder head myself right now. Basically I managed to strip all of the studs so I replaced them all. When I put the head back I used some crappy nuts which stripped and now I got to removed the nut aswell as redo the studs as they have been damaged while trying to remove the nuts.

The problem is I used some stupid epoxy resin based blue to stick in the studs, which is making it difficult to to remove them. LOng hours will no doubt be spent working on it next week.
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Old 07-26-2008, 05:44 PM
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Default Re: Head Leak

Holy moly. To get fasteners with Loctite out, just heat them with a heat gun.
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Old 07-26-2008, 05:54 PM
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Default Re: Head Leak

Well I've dicovered that this epoxy based stuff (araldite I think it's called) can be broken down using solvents, white spirit (naptha as I believe it's known in the USA) seems to work So when I get the head of I'll put some white spirit on the threads of the studs to get them out, or I'll heat them up, or maybe I'll be able to get a decent enough grip on the studs with the head of to remove them.
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Old 07-26-2008, 07:56 PM
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Default Re: Head Leak

F#*!# sake, set the flippin tension wrench to 12ft/lbs as noted on the instructions & bang the nuts have threaded, off now to the store to get some high tension M8/1 nuts & try again, I know how you feel mate, just had wished I logged on before I tried to tension my head again & would have read your thread & I would have lowered the setting for precautions, cant understand though Ive done everything exactly as stated on the instructions?, anyway its 9.20am in Australia on a Sunday, will need to wait another 1/2 hour before shops open,
Fantastic idea about lapping the head, I will have to order another head gasket just in case it still leaks, this is going to take a few more days before I receive it though, spewing its a cracker of a day & hanging to ride my new spanking bike all over the place, bu the way when you all state aluminium paint, I have never seen this in stores over hear?

Cheers all
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