Honda-SOHC

SOHC.co.uk Forums => CB500/550 => Topic started by: MikeM on July 12, 2014, 11:35:20 AM

Title: exhaust stud ..... welding the head
Post by: MikeM on July 12, 2014, 11:35:20 AM

while I wait for a repair shop answer I have emailed a few local machine shops

a few have said they can fill the exhaust stud hole with weld and retap back to original m6 but this may cause head to warp causing more work to be needed

ie machining the flat surface and possible work on valves and stems

advice needed on this one..... starting to think might as well get a new head

Title: Re: exhaust stud ..... welding the head
Post by: Paull on July 12, 2014, 12:15:30 PM

Hi MikeM,

I Have had stripped 6mm treads in a 650 head I made special studs.

This is how i did it, Drill stud hole to 6mm, tap tread to 7mm, take 7mm round rod and tread, turn down the bit that sticks out to 6mm and tread it, done. Or you could see if the 7mm tread will go through the exhaust clamp, 7mm nut, job done. 

No Heat, No twist

Just a thought.

Works for me.

Paull

Title: Re: exhaust stud ..... welding the head
Post by: Bryanj on July 12, 2014, 12:37:53 PM

There should be enough meat to tap out to 8mm and make a stepped stud to fit as 7mm taps are not always that easy to get

Title: Re: exhaust stud ..... welding the head
Post by: MikeM on July 12, 2014, 04:15:06 PM

it has been tapped to m8, I have the m8 to m6 stud, problem is the m8 heicoil pulls out ?

machine shop not interested in small job

Title: Re: exhaust stud ..... welding the head
Post by: Paull on July 14, 2014, 01:06:13 PM

Hi MikeM

What size is the hole that is stripped ?

I assume you have a 10mm hole for an 8mm helicol.

Just retread the hole to whatever size will hold, give me a shout and I will make you a stud to fit.

Hope this helps.

Paull   

Title: Re: exhaust stud ..... welding the head
Post by: MikeM on July 14, 2014, 03:56:58 PM

 I have used the m8x1.25x10.8 mm neilsen kit, used the drill and tap in the kit

aluminium seems really soft and wont take the tap for some reason hence the helicoil pulls out

am currently going down the route of replacing head as unable to get someone to weld and retap back to m6

Title: Re: exhaust stud ..... welding the head
Post by: Paull on July 14, 2014, 08:09:33 PM

Hi MikeM

Aluminum is soft, compared to steel and helicoils are tempered steel to stop them snapping out.

It sounds as if you are running out of options, a good ali welder or a new head, sorry to say.

Paull

 
 

Title: Re: exhaust stud ..... welding the head
Post by: MikeM on July 14, 2014, 09:40:18 PM

yeah i have a new head coming and a more experienced guy on it to repair mine

will be sorted shortly  :)

Title: Re: exhaust stud ..... welding the head
Post by: Paull on July 15, 2014, 02:47:47 PM

Cool Let us know how you get on.

Paull

Title: Re: exhaust stud ..... welding the head
Post by: Bitsa (Ralph Wright - RIP) on July 15, 2014, 02:55:54 PM

Mike
I had a mate Ali weld a spare alternator cover which had a hairline crack in it.When I got it back I was so surprised at how hard it was to grind down.So going on that basis your head if done the same way will come out as new and stronger.
Best of luck
Bitsa