Bolt thread size?

Shovelheadstroker77

Shovelheadstroker77

Club Member
Hi
IMG_20220625_130050~2.jpg

I am trying to find out what the thread size is of the 3 bolts that hold a Mikuni HSR carb adapter onto the filter backing plate (presmably the same as used as standard on the CV carb interface). I am adapting a screaming eagle plate and want to use hex headed bolts so I can drill holes through them for safety wire as they will reside inside the filter and my paranoia does not sit well with potentially unsecure bolts going internal.
 
I think as they are mikuni they are a metric thread when i have fitted before the should be a drop of thread locker used and the correct s/eagle back plate should not need adapting ?
 
Thanks - It's a SE plate originally for the '96 EFI which was on the bike (I like adapting things and saving a few quid as opposed to just buying the bits and bobs from a catalogue) just found out it's the same thread as on the 3 studs that hold the filter onto the plate but still don't know what the thread size is, it's not metric though.
 
I have used Spalding Fasteners for Nuts and Bolts and found them excellent. Great prices, low postage costs and very fast delivery, a lot quicker than E-bay. :encouragement:
 
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Shovelheadstroker77 said:
Hi
View attachment 1189783.......... I can drill holes through them for safety wire as they will reside inside the filter and my paranoia does not sit well with potentially unsecure bolts going internal.
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Hi.
Gooood idea. All the hardware that could possibly enter the carb ought to be safetied with one form or another.
You might save yourself a spot o'trubble, if only you'll check with your local FBO or aircraft supply house you will find out that 1/4-20 drilled-head bolts are quite common. Aircraft tend to not use coarse thread but 1/4-20 and smaller are one of the exceptions.

Positive-neutral-negative wiring; I'm guessing you know of that already.
 
For that application i have always used red loctite. And never had an issue over tens of thousands of miles.

Same with comp sprocket nut.

It has always baffled me how people are nervous about the red, and use air impact tools to remove comp sprocket nut.

I have never had to use air tools for anything***, and never had an issue undoing a bolt/screw that had red Loctite on it.

***I have never done serious bottom-end work myself.
 
Just a small point regards replacing that particular style of fastener, the thread is wider than the shank and for a purpose on the OEM fitment. The thread of the fastener passes through the air filter back plate to the carb/throttle body and the back plate is not held by or on the shank so as to give it some clearance to allow for alignment etc.
If you need this you do not want a shank that is as wide or wider than the thread.
 
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