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Z1000 A1 - Cylinder head 6mm side bolt stripped

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David32knyte
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Z1000 A1 - Cylinder head 6mm side bolt stripped

#1 PostAuthor: David32knyte » Fri Apr 03, 2020 8:38 pm

Dear Forum
One of the M6 side bolts (See pic) has stripped the thread in the barrels. So won't tighten properly, get so far then slips.

Does anyone have a recommendation for this?
Regular Helicoil insert? OR tap out and use oversize bolt?

I've heard some differing opinions so thought I 'd ask the forum.

Many thanks in advance

David
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CAT3
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Re: Z1000 A1 - Cylinder head 6mm side bolt stripped

#2 PostAuthor: CAT3 » Fri Apr 03, 2020 9:33 pm

Definitly go for the helicoil option.
Depending upon your level of competance you might be able to fit a helicoil in situ, but really the best option would be to remove the barrel to fit the helicoil. Once fitted correctly a helicoil thread will be stronger than the original tapped hole.

I woud never drill out something like this to fit an over-size bolt.

David32knyte
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Re: Z1000 A1 - Cylinder head 6mm side bolt stripped

#3 PostAuthor: David32knyte » Fri Apr 03, 2020 10:11 pm

Hi CAT3
OK thanks for your thoughts.
I've got to take the barrels off anyhoo so that's no problem. Leaky base gasket!
Now we've all got some spare time...

OK helicoil. May even do both as they seem a bit prone to this.

David

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Re: Z1000 A1 - Cylinder head 6mm side bolt stripped

#4 PostAuthor: zed1015 » Fri Apr 03, 2020 10:38 pm

Has to be Helicoil or time sert.
There's a hollow steel dowel that locates the head on the barrel in that location so an oversize bolt is not practical.
And yes! do both as the other is guaranteed to strip when you put it back together if you don't.

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Re: Z1000 A1 - Cylinder head 6mm side bolt stripped

#5 PostAuthor: Mr Bump » Sat Apr 04, 2020 8:31 am

Take it from one who has learned the hard way.... its hard to drill accurately through the stripped hole perfectly square from all directions with a hand held drill, especially if the head is fitted to the bike.

If at all possible get the head off and drill the hole out using a pillar drill - you risk it all going horribly wrong if you don't.

Olly
'In your twenties you think you are immortal, in your thirties you hope you are immortal, in your forties you just hope it doesn't hurt too much'

Lemmy

David32knyte
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Re: Z1000 A1 - Cylinder head 6mm side bolt stripped

#6 PostAuthor: David32knyte » Sat Apr 04, 2020 10:56 am

[quote="zed1015"]Has to be Helicoil or time sert.
There's a hollow steel dowel that locates the head on the barrel in that location so an oversize bolt is not practical.
And yes! do both as the other is guaranteed to strip when you put it back together if you don't.[/quote]
OK thanks - Yes bound to strip on the other side.

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Re: Z1000 A1 - Cylinder head 6mm side bolt stripped

#7 PostAuthor: DavidZ1R » Sat Apr 04, 2020 11:36 am

Mr Bump wrote:Take it from one who has learned the hard way.... its hard to drill accurately through the stripped hole perfectly square from all directions with a hand held drill, especially if the head is fitted to the bike.

If at all possible get the head off and drill the hole out using a pillar drill - you risk it all going horribly wrong if you don't.

Olly

Second that, doh!
CB125 GT380 CB750F1 Z1R GPZ 750 Turbo Z1R

David32knyte
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Re: Z1000 A1 - Cylinder head 6mm side bolt stripped

#8 PostAuthor: David32knyte » Wed Apr 08, 2020 10:00 am

Thanks everyone for your good advice.
Best
David

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chrisNI
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Re: Z1000 A1 - Cylinder head 6mm side bolt stripped

#9 PostAuthor: chrisNI » Wed Apr 08, 2020 4:10 pm

Also worth noting 6 or 7 ft/lb is plenty for these some of the manuals state 12 ft/lb which is too much and why they tend to strip, same with cam cap bolts.

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DogsbolloxofZ1B
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Re: Z1000 A1 - Cylinder head 6mm side bolt stripped

#10 PostAuthor: DogsbolloxofZ1B » Wed Apr 15, 2020 9:41 pm

Just had to do this on latest ‘72 engine build.
If you can go the Timesert route as a superior
product to helicoils but tooling isn’t cheap.
I’ve got one side that I used a Timesert and the
other was oversized so required an insert, I used
an A2 Self tapping M6 ST ST insert supplied by a
company called ACCU
www.accu.co.uk punch in the A2 text above.

Cheers Mike

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Re: Z1000 A1 - Cylinder head 6mm side bolt stripped

#11 PostAuthor: kev edwards » Thu Apr 16, 2020 5:31 am

Mike, been using them a long time where there is sufficient wall around them, they are good.


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