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SOHC.co.uk Forums => CB350/400 => Topic started by: billdn on August 13, 2017, 04:40:44 PM

Title: stripped thread on cylinder head
Post by: billdn on August 13, 2017, 04:40:44 PM
Following my earlier post on fitting rocker box and subsequent advice all went well..until..on tightening bolts down I noticed 1 nearest cam chain to rear wasn't tightening on cylinder head, yup the thread is stripped. I guess fit helicoil repair. And I suppose i need to remove cylinder head to do it. One step forward three back. Unless of course you sages know better!


Title: Re: stripped thread on cylinder head
Post by: Trigger on August 13, 2017, 05:22:23 PM
Following my earlier post on fitting rocker box and subsequent advice all went well..until..on tightening bolts down I noticed 1 nearest cam chain to rear wasn't tightening on cylinder head, yup the thread is stripped. I guess fit helicoil repair. And I suppose i need to remove cylinder head to do it. One step forward three back. Unless of course you sages know better!

What thread has striped ? If it is just a 6mm, then cover the top of the head in clingfilm, make a small hole were you need to do the helicoil and put a bit of tissue covered in Vaseline so the swarf sticks to it. Hoover out the thread hole once tapped and insert the coil.
Title: Re: stripped thread on cylinder head
Post by: kevski on August 13, 2017, 05:38:44 PM
Following my earlier post on fitting rocker box and subsequent advice all went well..until..on tightening bolts down I noticed 1 nearest cam chain to rear wasn't tightening on cylinder head, yup the thread is stripped. I guess fit helicoil repair. And I suppose i need to remove cylinder head to do it. One step forward three back. Unless of course you sages know better!

What thread has striped ? If it is just a 6mm, then cover the top of the head in clingfilm, make a small hole were you need to do the helicoil and put a bit of tissue covered in Vaseline so the swarf sticks to it. Hoover out the thread hole once tapped and insert the coil.

Pretty much the same as trigger says except use time-sert's far better though more expensive.
Title: Re: stripped thread on cylinder head
Post by: Trigger on August 13, 2017, 05:52:45 PM
Insert's for through holes, helicoils for blind holes in my book  ;) Beware: There are some shite inserts and helicoils about.
Title: Re: stripped thread on cylinder head
Post by: billdn on August 13, 2017, 07:24:46 PM
Yes it's 6mm. One of middle four on the head that has 2 either side of the cam chain. It's the rear right , from front of engine. I've only got a bog standard hand drill, will I get hole straight enough with that? I suppose original hole will act as guide. 
Title: Re: stripped thread on cylinder head
Post by: Trigger on August 13, 2017, 09:26:30 PM
Yes it's 6mm. One of middle four on the head that has 2 either side of the cam chain. It's the rear right , from front of engine. I've only got a bog standard hand drill, will I get hole straight enough with that? I suppose original hole will act as guide.

Can be done with a hand drill with a good steady hand. If you live near me I could do it in 10 minutes.
You will need a kit like this >>http://www.ebay.co.uk/itm/M6-x-1-0-V-Coil-Fits-Helicoil-Wire-Thread-Insert-Repair-Kit-/122614442826?epid=1424642313&hash=item1c8c63eb4a:g:oSIAAMXQ9MVRiSHc

But, you will still need a tap wrench.
Title: Re: stripped thread on cylinder head
Post by: mike the bike on August 14, 2017, 05:43:08 PM
The helicoil kit I got from fleabay comes with an M7 x 1 tap, ab0nd the correct size drill bit,  the insert tool and a punch to knock the tang off.
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