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Discussion Starter #1
I own a GL1000 that I bought from my dad. He bought it new in 1978. So I have the full history.

I just meticulously cleaned the carbs as it was running rough and had a plugged jet, as well as 2 plugged Idle jets. Once I go the carbs done, it ran better than I think it has ever ran for me. I took it for a ride around town, and just before I got home, it wasn't running correctly. I blew out a head gasket.

My problem is I don't know which head gasket to buy. My dad had this bike rebuilt and thus "bored out." The bore on the cylinder measures 75.5mm. Which is 3.5mm bigger than what it should have been at 72mm stock I believe. I actually looked back at the receipt from the mechanic that did the rebuild and there isn't anything listed there for machining work.

The head gasket that was on it is clearly narrower at 72.5-73 ish mm per cylinder. The serial number on the motor is for sure a GL1000. The engine wasn't changed by the mechanic who worked on it. I guess the mystery doesn't really matter to anyone, but should I get the head gasket for the 1100/1200 given that my bore size is so much bigger than the standard gl1000 bore?

TIA
 

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'93 GL1500 Aspencade '80 GL1100 STD Vetter
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786 Posts
I think they're all the same gasket anyway....
 

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'93 GL1500 Aspencade '80 GL1100 STD Vetter
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Right - I stand corrected. You might inquire over at the Naked Goldwings forum (ngwclub.com), there's a bunch of guys there with all sorts of custom modded bikes, might have some more comments.

My opinion is to use the 1100/1200 gasket, since the diameter of your bores is so much larger than stock half of the 1000 gasket's crush ring will be inside the bores and doing no good.
 

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I own a GL1000 that I bought from my dad. He bought it new in 1978. So I have the full history.

I just meticulously cleaned the carbs as it was running rough and had a plugged jet, as well as 2 plugged Idle jets. Once I go the carbs done, it ran better than I think it has ever ran for me. I took it for a ride around town, and just before I got home, it wasn't running correctly. I blew out a head gasket.

My problem is I don't know which head gasket to buy. My dad had this bike rebuilt and thus "bored out." The bore on the cylinder measures 75.5mm. Which is 3.5mm bigger than what it should have been at 72mm stock I believe. I actually looked back at the receipt from the mechanic that did the rebuild and there isn't anything listed there for machining work.

The head gasket that was on it is clearly narrower at 72.5-73 ish mm per cylinder. The serial number on the motor is for sure a GL1000. The engine wasn't changed by the mechanic who worked on it. I guess the mystery doesn't really matter to anyone, but should I get the head gasket for the 1100/1200 given that my bore size is so much bigger than the standard gl1000 bore?

TIA
It is not unusual for manufacturers to substitute and not say anything. I wonder if your bike was manufactured during the end of a model year run and it got an 1100 cc engine as all the 1000 cc engines were gone. The spec you list is the bore for an 1100. First choice would be a head gasket for an 1100 though I'm sure a 1200 would have no issues.
 

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That’s only .062 thousands per side,1200 would be fine I think.they are 76 mm
1100 is 75 mm
 

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1985 GL1200 Limited Edition
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Kieran, If it were my bike I would ask this question over at Naked Goldwings and direct the question to a guy named Randakk. He is THE Guru on all things GL1000 and rebuilt/modified/restored more GL1000's than we probably have ever seen!! He should have a firm answer for ya and might even be able to supply you with the proper gasket!
 

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Discussion Starter #8
Thanks guys for the quick response. I'm pretty puzzled as to why the bore was that big. My Dad was confident that they bored it, but I don't know why it wasn't charged on the invoice. That said the 1100 and 1200 gaskets are the same, so that it what I will likely go with. I'll touch base on the other forum and see what they say!

As far as them sneaking in a 1100 block when they manufactured, I don't think the 1100's came out till 80 and this bike is a 78. But anything is possible.
 

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02 GL1800 w/Auto Pilot
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I was not aware that over size pistons are/were even available for the Goldwings.
 

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Up to 1mm are in the parts book, over that i wouldnt want to reassemble the engine, its enough of a ballsache to get the 2nd 2 pistons in with the the original taper in the bores!!!!
 

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Discussion Starter #11
I was not aware that over size pistons are/were even available for the Goldwings.
I imagine that if it were bored then perhaps that is why they ended up going that big on the bore, because they had to source a 1100 piston perhaps...
 

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That only works if it is an oversize on a 1000, if they fitted 1100 pistons it may say nothing(standard) for the difference in bores you should be able to use a steel rule down to 0.25mm.

Just as an example on sizes i am boring a 500 four block to fit 550 +0.25 pistons so the pistons will have 0.25 on them but its actualy 2.75mm oversize, reason for that size is price of pistons and its my boring bar so i dont pay for the time!
 
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