Engine won’t start, screeches then shuts off

Wrench

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Nov 14, 2018
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4,151
Yes, still a small head gasket leak. It’s nothing terrible. It still creates vacuum and doesn’t lose too much power. Though I haven’t been able to start it to check recently. The leak is all over but mostly on the exhaust side. The spark plug works fine. Just tapped the prongs down a little bit, there is still a good amount of space and it still creates spark fine. Could you elaborate on the screeching sounds that could be caused by the leak?
A head gasket leak will never correct itself it will always get worse. Unless it's just some loose head bolts.

The compression air escaping creates a sound as it passes the gasket. A squeak or screech also a tick sound from the gasket vibrating.

It's important you have the correct Spark Plug gap - Between .025" and .030"
If you don't have a feeler gauge to gap your Spark Plug, Just use your Drivers License, the plastic is between .025" and .030" Perfect for gaping a Spark Plug.

A head gasket leak will also make your bike run lean - HOT

I suggest to resurface the head deck and make sure it's flat
Resurface the head by rubbing the head on a piece of 220 grit sandpaper on plate glass or any known 100% flat surface.
Put Black sharpie marks on the head deck When all the sharpie marks are gone the head is flat.
Also check your work while sanding, You'll be able to see any low spots

Use a new Copper head gasket too
 
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Wrench

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Nov 14, 2018
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4,151
Yes, still a small head gasket leak.
BTW after you have resurfaced the head and installed a new head gasket, If you still have a head gasket leak, this means that the cyl deck is warped and the cyl deck will need to be resurfaced too. The same way ya resurfaced the head

TIP so ya don't chase your tail, Make sure your acorn nuts are not bottoming out and running out of threads. The head will always leak
Good Idea to switch to regular nuts
 
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BrodyLawrence

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Jun 5, 2021
Messages
7
BTW after you have resurfaced the head and installed a new head gasket, If you still have a head gasket leak, this means that the cyl deck is warped and the cyl deck will need to be resurfaced too. The same way ya resurfaced the head

TIP so ya don't chase your tail, Make sure your acorn nuts are not bottoming out and running out of threads. The head will always leak
Good Idea to switch to regular nuts
Thanks so much for the help! I’ll get to work on replacing the head gasket because it seems to be a bit warped and I’ll try to sand down the head👍
 

yuckfoo

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Joined
Nov 21, 2020
Messages
705
A head gasket leak will never correct itself it will always get worse. Unless it's just some loose head bolts.

The compression air escaping creates a sound as it passes the gasket. A squeak or screech also a tick sound from the gasket vibrating.

It's important you have the correct Spark Plug gap - Between .025" and .030"
If you don't have a feeler gauge to gap your Spark Plug, Just use your Drivers License, the plastic is between .025" and .030" Perfect for gaping a Spark Plug.

A head gasket leak will also make your bike run lean - HOT

I suggest to resurface the head deck and make sure it's flat
Resurface the head by rubbing the head on a piece of 220 grit sandpaper on plate glass or any known 100% flat surface.
Put Black sharpie marks on the head deck When all the sharpie marks are gone the head is flat.
Also check your work while sanding, You'll be able to see any low spots

Use a new Copper head gasket too
My Pennsylvania driver's license is 0.032 same as my debit card. You can usually find an inexpensive gap checker at the counter area of your local auto parts store. If you have Amazon Prime you can get one for less than $3.00 with free shipping.

 

Wrench

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Nov 14, 2018
Messages
4,151
My Pennsylvania driver's license is 0.032 same as my debit card.
.032" is close enough in an emergency. Actually the S/P gap can be between .020" and .040" and still run OK
But .025' to .030" is best for your M/B S/P


It's important you have the correct Spark Plug gap - Between .025" and .030"
If you don't have a feeler gauge to gap your Spark Plug, Just use your Drivers License, the plastic is between .025" and .030" Perfect for gaping a Spark Plug.
 

Karl Snarl

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Sep 20, 2019
Messages
3,397
Screech is clutch, tick is piston hitting head gasket. Ream it out a little or make sure it sits correctly before installing the head.
 
Joined
Sep 13, 2019
Messages
38
Give this a shot pull the clutch cover and look on the back side of cover a see if there groves in it. Just a idea . Be safe and hope this help.
This is what I was thinking. Screeching noise, for me has always been behind the clutch cover (right side sitting on the bike)
 
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