Center Head Bolt?

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Hungry J0e

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I've got a few hundred miles on my restored 850, and trying to torque down the head bolts. I have whitworth 3/8" drive sockets and deep sockets. I can get all the head bolts except the front center one (which all the manuals tell me is the first to be torqued down...). I'm guessing it is a 1/4" whitworth... any options out there other than grinding down one of my nice new sockets?

Cheers,

- HJ
 
Every job has a proper tool. Whitworth fasteners require whitworth tools.
 
JimC said:
Every job has a proper tool. Whitworth fasteners require whitworth tools.
Click to expand...

Absolutely true, but they're not universally available :(
The headbolts are 5/16", amd RGM do a spanner which fits the rear underside nut. I found that a Snap-On 3/8" drive 14mm flank-drive socket fits the front nuts & centre bolt well enough, but I'm not condoning this :oops:

I'm still looking for 3/8 drive sockets if anyone has any leads...
 
B+Bogus said:
I'm still looking for 3/8 drive sockets if anyone has any leads...
Click to expand...

I bought a good set from British Spares in New Zealand a couple of years ago. Koken (Japanese) made and nice quality. They are on the Internet.
 
Hungry Joe is from Florida. I would bet every Norton parts supplier in the U.S. has them for sale. I would think the British probably have no trouble finding them most anywhere.
 
B+Bogus said:
The headbolts are 5/16",
Click to expand...

Hexagon/jaw size should be 0.525", which 5/16 BS or 1/4 Whitworth.


JimC said:
I would think the British probably have no trouble finding them most anywhere.
Click to expand...


It's rare to find BS/Whit. tools in UK hardware/DIY stores these days!
 
swooshdave said:
You're in the Motherland of Whitworth, if you can't find them there...
Click to expand...

A gradual change over to METRIC fateners & tools took place here in the UK, which started around 30 years ago, so practically all tools and fasteners are now metric! And British Standard fasteners and tools were already out of general use because most manufacturing industries in the UK had already changed over to UNIFIED threads!
 
L.A.B. said:
swooshdave said:
You're in the Motherland of Whitworth, if you can't find them there...
Click to expand...

A gradual change over to METRIC fateners & tools took place here in the UK, which started around 30 years ago, so practically all tools and fasteners here are now metric! And British Standard fasteners and tools were already out of general use because most manufacturing industries in the UK had already changed over to UNIFIED threads!
Click to expand...

I was kind of kidding. :mrgreen:

But still there are still a number of places around the world to get Whitworth.
 
Jim -

My original post was not very clear... I apologize...

I have 3/8" drive Whitworth sockets, deep sockets, and spanners. My question was what is the center head bolt, as it was too big for my 1/4W socket... I assumed it was a 5/16W, but my socket would not fit down the hole, so I was wondering what others out there were doing.

After a pulling off the coils and head steady so I could get a better look in there, it turns out my center head bolt is a 9/16" SAE... No idea how it got there, but that's how it is... All the others are 1/4W or 3/16W as appropriate.

Anyways, new problem. Torqued everything down, and when putting the 20 ft-lb (with a torque wrench) on the last 3/16W headbolt the stud stripped out. So now I've got that to deal with...

Portion of the stud inserted into the cylinder had less thread on it than the portion with the nut on it... flipping the stud over, it looks like I've got about 1/4" of good thread in the cylinder, but I'm wary of using that...

Any ideas out there on how I can fix this? I'm guessing a proper fix is going to involve pulling the cylinders... *sigh*

Cheers,

- HJ
 
The stock studs are 3/8-20 x 3/8-26 BSC. Raber's have dual threaded 3/8" dia. studs. 3/8-16 UNC on one end and 3/8-26 BSC on the other. This enables you to use a standard 3/8" UNC Helicoil, yet retain the 3/8-26 BSC nuts. If I were to do it again I would use 3/8-16 UNC x 3/8-24 UNF studs and use 3/8-24 UNF nuts. I 'm sure there are inserts for 3/8-20 BSC, but I don't know where. It just makes more sense, to me anyway, to use a fastener that's readily available. Besides, the 16 tpi probably works better in aluminum than a 20 tpi. Now, if I haven't got my BSC's and BSF's mixed up.......
 
Hungry J0e said:
I've got a few hundred miles on my restored 850, and trying to torque down the head bolts. I have whitworth 3/8" drive sockets and deep sockets. I can get all the head bolts except the front center one (which all the manuals tell me is the first to be torqued down...). I'm guessing it is a 1/4" whitworth... any options out there other than grinding down one of my nice new sockets?

Cheers,

- HJ
Click to expand...

If it's the same as on a 750, I bought a set of British Std Snap-On sockets years ago. The front three nuts dropping into the head reqire 5/16 BS socket with a 3 inch extension then connects to my torque wrench easily (with a 1/2-3/8 drive converter).
 
JimC said:
The stock studs are 3/8-20 x 3/8-26 BSC.
Click to expand...

From Joe's description, I understood it to be one of the two 5/16" 067561 studs ( numbers 9 & 10 when re-torquing) which screw into the top of the barrels that has pulled out?
Both ends of that stud are 26 tpi CEI/BSCy thread I think. Although I don't understand your reference to it being a "3/16W headbolt", Joe?

Hungry J0e said:
Torqued everything down, and when putting the 20 ft-lb (with a torque wrench) on the last 3/16W headbolt the stud stripped out.

Portion of the stud inserted into the cylinder had less thread on it than the portion with the nut on it... flipping the stud over, it looks like I've got about 1/4" of good thread in the cylinder, but I'm wary of using that...
Click to expand...
 
L.A.B. said:
From Joe's description, I understood it to be one of the two 5/16" 067561 studs ( numbers 9 & 10 when re-torquing) which screw into the top of the barrels that has pulled out?
Both ends of that stud are 26 tpi CEI/BSCy thread I think. Although I don't understand your reference to it being a "3/16W headbolt", Joe?
Click to expand...

Yeah those are also 1/4W. The only 3/16W headbolts are the two funky nuts at 7 & 8.
 
Hey Joe,

Which studs are you referring to? 5/16" or 3/8"? If it's the 5/16", do you have aluminum barrels? I've never had the 5/16" studs strip out of iron barrels, so I assumed you were speaking of the two 3/8" studs, #48. Or were you referring to the two 5/16" studs #47?
Center Head Bolt?
 
On my 750 the center bolt is the same size as the outside 4 so whatever fits on them fits the center.
 
Gents -

Yes it is indeed #47... listed as a 5/16" stud in my Clymer manual. 3/16W was referencing the whitworth socket I have to use to tighten the nut, which reads 3/16W... sorry for the confusion... this is my first foray into whitworth fasteners...

Stud did indeed strip out of the iron barrel well before max torque. I use a clicker type torque wrench, lesson learned there I guess... Anyway, by inverting the stud so the longer threaded portion is in the barrel, I have about 1/4" of good thread left. Plan is to use some stud lock on it and taking it a bit easy on the torque... if it won't take a reasonable torque, then it's off with the head so I can access the cylinder for a more robust repair...

Cheers,

- HJ
 
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