Exhaust Stud Resizing


Information and questions on GL1500 Goldwings (1988-2000)
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Solopilot
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Joined: Sun Mar 27, 2022 10:23 pm
Location: Canada
Motorcycle: 1997 GL1500 Aspencade

Exhaust Stud Resizing

Post by Solopilot »



Hey all, I've decided to go through and track down a few exhaust leaks in my 1500, in the process I snapped off 9 outta 12 exhaust studs. No big problem really, I have all pieces removed for the heads and what not. As some of you may know the exhaust stud steps down from a 8mm in the head to a 6mm on the exhaust header side.

My question is, other than some minor drilling/machining on the exhaust header to accommodate 8mm diameter stud , is there any issue I am missing with putting 8mm studs that do not step down (8mm to 8mm instead of 8mm to 6mm)? Any input is greatly appreciated.

Thanks in advance, Greg


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Charlie1Horse
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1992 GL1500I Interstate
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Re: Exhaust Stud Resizing

Post by Charlie1Horse »

Possibly would not have enough room for wrench to tighten them with a larger nut. Could be too close to the header pipe. I would do some measuring and calculate just how much room there would be in there. I don't see any problem with doing that if you can get a wrench on the nut to be able to tighten it to proper torque.
And drilling a steel stud in an aluminum head could be a problem anyway if you are not experienced at it.
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Rambozo
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Re: Exhaust Stud Resizing

Post by Rambozo »

I doubt there is enough clearance around the exhaust header for a standard 8mm nut and/or a tool to tighten it. While there are some exotic solutions, a stepped stud is an easy way to solve the problem.
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ct1500
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Re: Exhaust Stud Resizing

Post by ct1500 »

For anyone else following always heat the nuts as insurance prior to removal as it will prevent breakage of the studs. ;)
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landisr
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Re: Exhaust Stud Resizing

Post by landisr »

6mm helicoils with 6mm studs?

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Solopilot
Posts: 7
Joined: Sun Mar 27, 2022 10:23 pm
Location: Canada
Motorcycle: 1997 GL1500 Aspencade

Re: Exhaust Stud Resizing

Post by Solopilot »

Thanks everyone for your input and advice. Next time I will try some heat if needed, wish I knew that one before 9 had snapped lol.

Socket clearance was a concern of mine, but other than a little bending of the heat shield there is actually a fair amount of clearance, so I should be good there.

Just for clarification, I'm not drilling the engine head or in need of thread repair. I plan on using exhaust studs that are 8mm at both ends (same as what the engine cylinder head is threaded from factory) so no step down to 6mm on the exhaust header side. Hoping this will be a stronger setup and will hopefully avoid the stud snapping if I ever need to remove them again. The other side of the coin why I would like to do this is cost savings, twelve 8mm/6mm Honda exhaust studs and twelve 6mm special nuts are over $200 Canadian.

Thanks Again, Greg
Solopilot
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Joined: Sun Mar 27, 2022 10:23 pm
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Motorcycle: 1997 GL1500 Aspencade

Re: Exhaust Stud Resizing

Post by Solopilot »

Well, I went and tried a test fit, and unfortunately there simply isn't enough wiggle room with 8mm studs to get the header to slide over them. You would have to open the exhaust bolt holes to approx. 9mm, and there isn't enough material there for me to be confident that they wouldn't crack or fail in some way. Thanks everyone for your input, on to the next adventure.

Thanks, Greg
pocketchange
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Motorcycle: 1994 GL1500 SE

Re: Exhaust Stud Resizing

Post by pocketchange »

I'd bet a machine shop could make you whatever you need, cheaper than what
the troops at Honda will sell you the studs.. pc


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