Author Topic: Small Hole in the Engine Cylinder Head of my G5 !  (Read 12080 times)

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singhg5

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on: August 22, 2010, 12:53:36 am
After I came back from my ride today, I noticed that there is a 2 mm diameter hole on the RIGHT side of engine, in between bottom two fins of cylinder head of my motorcycle G5.  It also was wet with a bit of oil - seems to be coming out of it.

Is this hole normal ?  If so, is it supposed to leak oil ?

Here is a picture.
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r80rt

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Reply #1 on: August 22, 2010, 01:10:52 am
My C5 has one just like that, no oil though,
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singhg5

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Reply #2 on: August 22, 2010, 01:20:07 am
My C5 has one just like that, no oil though,

You mean your C5 and my G5 engines were made by the same guy ?  :D

What is the purpose of this hole ?  
« Last Edit: August 22, 2010, 01:23:27 am by singhg5 »
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ScooterBob

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Reply #3 on: August 22, 2010, 02:20:00 am
Relax - It's just a cross drill oil hole used to connect the hole in the base of the cylinder with the hole that goes THROUGH the cylinder to oil the top end. After the passages are connected, the outside is plugged. That's what you are seeing. It ain't no thaing!  ;)
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singhg5

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Reply #4 on: August 22, 2010, 02:45:30 am
Relax - It's just a cross drill oil hole used to connect the hole in the base of the cylinder with the hole that goes THROUGH the cylinder to oil the top end. After the passages are connected, the outside is plugged. That's what you are seeing. It ain't no thaing!  ;)

If you open the picture in new tab and enlarge (+) the picture, you will see oil coming out of it - what do you make of that ? 
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ScooterBob

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Reply #5 on: August 22, 2010, 03:39:17 am
If you open the picture in new tab and enlarge (+) the picture, you will see oil coming out of it - what do you make of that ? 

Well - There IS oil under pressure behind it ...... If it were MINE, I'd just peen the cylinder a little around the plug (if it leaked a drop big enough to drip) and be done with it.
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2bikebill

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Reply #6 on: August 22, 2010, 09:11:53 am
My G5 has that hole too Singh - no oil though, yet.....
Don't forget that fully synth oil finds its way to places other oils don't.....
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SSR

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Reply #7 on: August 22, 2010, 04:09:14 pm
This hole is for the water drainage around the plug. Try putting some water on to the plug and see it for yourself.


singhg5

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Reply #8 on: August 22, 2010, 04:18:42 pm
This hole is for the water drainage around the plug. Try putting some water on to the plug and see it for yourself.

US models have only one spark plug which is on the left side of the engine, unlike Indian models that have two spark plugs.  No spark plug on the right side, here.

Will try to put some water on the left side and see what happens !  Thanks.
« Last Edit: August 22, 2010, 04:37:30 pm by singhg5 »
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r80rt

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Reply #9 on: August 22, 2010, 04:25:05 pm
SSR is right, it's a water drain.
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singhg5

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Reply #10 on: August 22, 2010, 04:32:04 pm
SSR is right, it's a water drain.

You mean water from spark plug on the left side of engine drains through this hole on the right side ?
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ScooterBob

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Reply #11 on: August 22, 2010, 04:37:08 pm
OK - I'm pullin 'a cylinder off the shelf to SEE what this is ....... Hold that thought 'til Monday  ???
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r80rt

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Reply #12 on: August 22, 2010, 04:44:04 pm
Pour some water on the right side where the second plug would be if you had one, it will run out of the hole.  Nothing mysterious about it.
« Last Edit: August 22, 2010, 05:05:04 pm by r80rt »
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SSR

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Reply #13 on: August 22, 2010, 06:16:50 pm
You mean water from spark plug on the left side of engine drains through this hole on the right side ?

Singh JI, all the UCE engine have only one water drain on the RH side weather its domestic or export C5.

The one and only primary plug you have does not have a drain hole like on RH side. There is a gap between the fins and the block near the LH side head bolt(next to primary plug) Water does not collect there.

While on Rh side where there is a secondary plug or in export models just a deep cavity. On RH side the fins have metal to metal contact with the head without any gap(Rh side of head is wider then LH side) so they have intentionally had a drain hole because of the cavity form due to the head design.

The oil/moisture you see is from the barrel /head gasket. Tighten the head or replace the metal gasket if you dont want to see any oil there.


singhg5

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Reply #14 on: August 23, 2010, 01:09:31 am
Singh JI, all the UCE engine have only one water drain on the RH side weather its domestic or export C5.

The one and only primary plug you have does not have a drain hole like on RH side. There is a gap between the fins and the block near the LH side head bolt(next to primary plug) Water does not collect there.

While on Rh side where there is a secondary plug or in export models just a deep cavity. On RH side the fins have metal to metal contact with the head without any gap(Rh side of head is wider then LH side) so they have intentionally had a drain hole because of the cavity form due to the head design.

The oil/moisture you see is from the barrel /head gasket. Tighten the head or replace the metal gasket if you dont want to see any oil there.

Randhawa Ji:

Sat Sree Akaal.  You were right on.  It is a drain hole for the cavity on the right side of the cylinder head.  I put a paper clip wire through the hole and it came out on the other side - in the cavity.  

I saw some oil on the gasket between cylinder head and cylinder barrel.  That must have drained out through this hole a bit.

Thanks for great explanation.
« Last Edit: August 23, 2010, 02:57:15 am by singhg5 »
1970's Jawa /  Yezdi
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