Stripped intake manifold plug hole


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marasciallo
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Joined: Wed Aug 16, 2017 7:47 pm
Location: Charlotte (NC)
Motorcycle: '87 Honda XL 600 RM, '98 Honda VFR 800, '08 Yamaha XJR 1200, '12 Suzuki V-Strom 650

Stripped intake manifold plug hole

Post by marasciallo » Sun Mar 10, 2019 11:45 am



Hello everybody,
I'm desperate for some help here! :cry:
I was going to do a carb sync on my 1981 GL1100 that I recently restored.
While removing the intake plugs to put the adapters, I found the screw on cylinder no.1 doing too much resistance coming out.
With immense disappointment I found out the thread on the manifold is stripped and now I don't know how to manage it.

Can you please give me some advice on how to fix this issue? I never had this kind of issue before.
Helicoil? Widening the hole to 6 mm? I guess that everything will have to be done with the manifold out...

Thanks in advance for your precious help!

Paolo



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jaimenv
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Location: carolina puerto rico
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1986 gl1200 Interstate (Barney)

Re: Stripped intake manifold plug hole

Post by jaimenv » Sun Mar 10, 2019 12:14 pm

Trying to stay in the same size of hardware as the other 3 synchronizing plugs, I would go with the Heli coil. If the Heli coil changes the size of the hardware then and only then I drill and tap to the next available thread and size synchronizing hose barb.
Reason is if you drill and tap to a exotic size and thread, you may set your self in to a hard to find hardware.

In other words try to stay in the same spec when possible. Life is a lot easier when dealing with common hardware sizes/threads.

PS. When I encounter a bolt/screw that breaks loose and gets hard coming out I spray it with penetrating oil and screw it back in, then screw it back out. every time going a little more out and spraying more penetrating lubricant.
Also sometimes it helps to hit/tap the head of the bolt/screw to knock it loose.
My favorite home made penetrating lubricant is 50-50 acetone/atf. Beware the acetone is very flammable :twisted: .
Jaime
When there is some you don't want none, when there is none you want some :cry: .
You can please some people some of the time, but not all the people all of the time :roll: .
Do what you can, with what you have, while you can ;) .

marasciallo
Posts: 10
Joined: Wed Aug 16, 2017 7:47 pm
Location: Charlotte (NC)
Motorcycle: '87 Honda XL 600 RM, '98 Honda VFR 800, '08 Yamaha XJR 1200, '12 Suzuki V-Strom 650

Re: Stripped intake manifold plug hole

Post by marasciallo » Sun Mar 10, 2019 12:55 pm

Thanks Jaime,
I will check the helicoil, I'm not familiar with this kind of repair.
I'm also considering buying another manifold in better shape.

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Maz
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Motorcycle: 1975 GL1000K1
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Re: Stripped intake manifold plug hole

Post by Maz » Sun Mar 10, 2019 1:21 pm

marasciallo wrote:
Sun Mar 10, 2019 12:55 pm
Thanks Jaime,
I will check the helicoil, I'm not familiar with this kind of repair.
I'm also considering buying another manifold in better shape.
The Helicoil would be my choice too. Using the drill that comes with the kit, you drill the hole out, tap it oversize with the supplied tap, then wind in the Stainless Steel thread, which brings it back to original size. You will have to remove the manifold to prevent the swarf getting in the cylinder and also the little stainless tang that you have to snap off after fitting the thread.
Maz
Ironically, Common Sense is the LEAST common of all senses!

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DenverWinger
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1980 GL1100 STD Vetter (2005-)
1993 GL1500 Aspencade (2017-)
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Past rides
1972 CL350 (1980-1988) sold
1978 Suzuki GS550 (1985-2005) sold
1977 GL1000 (2002-2006) sold

Re: Stripped intake manifold plug hole

Post by DenverWinger » Sun Mar 10, 2019 5:31 pm

If you haven't lost too much metal from the manifold threads you may be able to clean them up with an appropriate size tap. There's nothing that screws in there (plug screw or vacuum barb) that needs any torque, only has to not leak. Once you've cleaned out the threads a rubber washer under a new screw just tight enough to seal may be enough to do the job.
♫ 99 Little Bugs in the Code, ♪
♪ 99 Bugs in the Code. ♫ :(
♫ Take one down, Patch it around, ♪
♫ 127 Little Bugs in the Code. ♫ ♪ :shock:

~Mark

marasciallo
Posts: 10
Joined: Wed Aug 16, 2017 7:47 pm
Location: Charlotte (NC)
Motorcycle: '87 Honda XL 600 RM, '98 Honda VFR 800, '08 Yamaha XJR 1200, '12 Suzuki V-Strom 650

Re: Stripped intake manifold plug hole

Post by marasciallo » Sun Mar 10, 2019 7:21 pm

Thank you all for your support.
I have the manifold out and here you can see a couple of pictures of the hole.
I think I'll give it a try to clean the thread as DenverWinger suggested before going Helicoil.
Any advice is always welcome too!







marasciallo
Posts: 10
Joined: Wed Aug 16, 2017 7:47 pm
Location: Charlotte (NC)
Motorcycle: '87 Honda XL 600 RM, '98 Honda VFR 800, '08 Yamaha XJR 1200, '12 Suzuki V-Strom 650

Re: Stripped intake manifold plug hole

Post by marasciallo » Sun Mar 17, 2019 5:17 pm

Just wanted to let you know that I've been able to clean the thread with a 5 mm tap.
Thank you all again for the suggestions!



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