Author Topic: A10 head gasket breakin  (Read 468 times)

Offline ALPH1

  • Moving Up
  • **
  • Join Date: Sep 2019
  • Posts: 27
  • Karma: 0
  • BSA GF 1959,74 Bonnie
A10 head gasket breakin
« on: 06.05. 2020 10:39 »
Hi all,

Well after pulling my hair out I found the issue of the black smoke, misfire and hard to start.. the main screw in the carb was put on the wrong thread at some point and was leaking plus the condenser was gone in the mag. 1 mag rebuild by a great guy in belfast and a recondishioned carb sorted it. Took the bike out and maybe with up a hill a little to hard when I felt blowing on my right knee. Head gasket blown. Thing is  I had replaced it when I changed the ring not 50k ago. So after reading and asking about I didn't used any compound on the copper gasket or did I aneel the copper . So this time I was anal about the replacement including the torque sequence.. the question is.. is there a running in period on the head gasket and if so what is it.. easy running etc.. also the bike has only done 50k isn't since the new rings. Thanks in advance. AL

Online KiwiGF

  • Last had an A10 in 1976, in 2011 it was time for my 2nd one. It was the project from HELL (but I learned a lot....)
  • Wise & Enlightened
  • *
  • Join Date: Feb 2011
  • Posts: 1606
  • Karma: 13
Re: A10 head gasket breakin
« Reply #1 on: 06.05. 2020 10:47 »
Hi all,

Well after pulling my hair out I found the issue of the black smoke, misfire and hard to start.. the main screw in the carb was put on the wrong thread at some point and was leaking plus the condenser was gone in the mag. 1 mag rebuild by a great guy in belfast and a recondishioned carb sorted it. Took the bike out and maybe with up a hill a little to hard when I felt blowing on my right knee. Head gasket blown. Thing is  I had replaced it when I changed the ring not 50k ago. So after reading and asking about I didn't used any compound on the copper gasket or did I aneel the copper . So this time I was anal about the replacement including the torque sequence.. the question is.. is there a running in period on the head gasket and if so what is it.. easy running etc.. also the bike has only done 50k isn't since the new rings. Thanks in advance. AL

One thing to check is that the torque wrench is accurate, mine is reputable brand but after the head gasket blew after a few hundred miles I investigated and found it over read by 30%  *problem*

Then i had to strip it completely, and redo the big end nuts  *problem* *problem* *problem* *problem*
New Zealand

1956 A10 Golden Flash (1st finished project)
1949 B31 rigid “400cc” (2nd finished project)
1968 B44 Victor Special (3rd project,in progress)
2001 GL1800 Goldwing, well, the wife likes it
2007 KTM 950 Adventure, cos it’s 100% nuts

Online berger

  • Wise & Enlightened
  • *
  • Join Date: Nov 2017
  • Posts: 1605
  • Karma: 9
  • keith.uk 500sscafe.norbsa project,honda 750fz
Re: A10 head gasket breakin
« Reply #2 on: 06.05. 2020 10:51 »
is it an ally head, if so you need a straight edge to see if you have any distortion using feeler gauges. it is uncommon but possible the block is a bit out as mine was and ended up being skimmed. always soften your gasket and what I do to save taking the rocker box off after a few miles to re-tighten is pull it down and leave it for at least a full 24 hours then try the bolts again. once I've given them an extra tighten I've never had one blow. I never use composite head gaskets only solid copper and have re used them with no problem once softened up before putting the head back on

Online Triton Thrasher

  • Scotland
  • Wise & Enlightened
  • *
  • Join Date: Feb 2009
  • Posts: 1620
  • Karma: 21
Re: A10 head gasket breakin
« Reply #3 on: 06.05. 2020 10:54 »
I do the first re-torque after getting the engine hot and letting it cool.

Offline ALPH1

  • Moving Up
  • **
  • Join Date: Sep 2019
  • Posts: 27
  • Karma: 0
  • BSA GF 1959,74 Bonnie
Re: A10 head gasket breakin
« Reply #4 on: 06.05. 2020 11:08 »
Good advise.. jesus I hope the torque wrench is not out!! Wasnt huge money but 100 quid so I do hope it correct. I ran it last  night for maybe 20 minute and I'll recheck the torque again today. 

Offline hdawson

  • A's Good Friend
  • ***
  • Join Date: Feb 2016
  • Posts: 108
  • Karma: 0
Re: A10 head gasket breakin
« Reply #5 on: 06.05. 2020 11:56 »
 My blown copper gasket is hanging on my ‘wall of shame’ in the shed.
Handy reminder of the mistakes I won’t repeat.
Anneal and copper gasket goo spray and re torque check three times at the intervals recommend by this forum et al.
Cheers all and wishing all the best for your families in these difficult times.
Hadrian.

61 BSA Super Rocket (cafe).
51 Matchless G9 Clubman.
81 Suzuki GSX 750 ES.
02 Triumph Sprint.

Online chaterlea25

  • Wise & Enlightened
  • *
  • Join Date: Jun 2009
  • Posts: 3525
  • Karma: 49
Re: A10 head gasket breakin
« Reply #6 on: 06.05. 2020 13:53 »
Hi All,
Alph does not say if the head is alloy or iron, in either case check that the head bolts thread down far enough and easily into the barrel
The washers on the head bolts squash and distort even on the iron heads
The faces on the head for the washers also distort
Make sure they are flat or get them spotfaced
I make 3mm thick washers for the bolts
machined from bar stock
Touch wood  *ex* I have not had to go back and retighten any of the heads on the engines I put together over the years

John 
1961 Super Rocket
1963 RGS (ongoing)

Offline ALPH1

  • Moving Up
  • **
  • Join Date: Sep 2019
  • Posts: 27
  • Karma: 0
  • BSA GF 1959,74 Bonnie
Re: A10 head gasket breakin
« Reply #7 on: 06.05. 2020 14:26 »
Thanks john.. the head is actually alloy. I noticed the bolts have washers and a split  washer on them and i replaced with new ones.. should it have both

Al

Offline bikerbob

  • Resident Legend
  • *****
  • Join Date: Feb 2011
  • Posts: 572
  • Karma: 7
Re: A10 head gasket breakin
« Reply #8 on: 06.05. 2020 14:31 »
My system is one that I have used for over 20 years without any problems. As regards the gasket I always use solid copper gaskets and always anneal them, I only ever use the same gasket twice after which I buy a new one don't ask me why I do this it is just something that I am comfortable with. As for tightening down I gradually tighten each bolt down in the correct sequence finishing up with the correct torque using a torque wrench. I then leave the bike for 24 hours and then re-torque the bolts, something else that I am comfortable with. When I am finished I always reset the torque wrench back to it's zero setting I never leave it set at anything above zero as I was told many years ago that this is what can cause torque wrenches to give a false reading.This torque wrench was given to me by my late father some 40 years ago and I did buy a new one afew years ago thinking the old one was maybe past it but it tested out perfectly against the new one.

Online berger

  • Wise & Enlightened
  • *
  • Join Date: Nov 2017
  • Posts: 1605
  • Karma: 9
  • keith.uk 500sscafe.norbsa project,honda 750fz
Re: A10 head gasket breakin
« Reply #9 on: 06.05. 2020 18:44 »
if you mean lock washers no they shouldn't be there, as john said about the washers he makes get thick ones for it and re read his post about flat surface for the washers, plus check the head with a straight edge

Online Triton Thrasher

  • Scotland
  • Wise & Enlightened
  • *
  • Join Date: Feb 2009
  • Posts: 1620
  • Karma: 21
Re: A10 head gasket breakin
« Reply #10 on: 07.05. 2020 09:56 »
Definitely thick plain washers only.

No wonder it came loose!

Offline ALPH1

  • Moving Up
  • **
  • Join Date: Sep 2019
  • Posts: 27
  • Karma: 0
  • BSA GF 1959,74 Bonnie
Re: A10 head gasket breakin
« Reply #11 on: 07.05. 2020 10:12 »
Jesus!! Seems the mistake this time  was not posting this before I put it back together. I'll have to strip it and take them out.. In not a fan of doing the rocker box and push rods.  Managed to do it in two goes this time with a tip I got by adding some greese to the socket the rods sit in.. but even with the tool and that it's not easy..

Online berger

  • Wise & Enlightened
  • *
  • Join Date: Nov 2017
  • Posts: 1605
  • Karma: 9
  • keith.uk 500sscafe.norbsa project,honda 750fz
Re: A10 head gasket breakin
« Reply #12 on: 07.05. 2020 10:30 »
I did mine a few weeks ago after finding a push rod problem, the rods are safe in the cam followers with oil and resist being pulled out, so get the engine turned so the rods are as equal as possible. then right angle-ish the comb so you can fasten it with a clamp to the top head fin leaving it a good flat fit on the head and get the rods in the correct slots. it is advisable to fix the gaskets to the rocker box firmly and then put the goo on the gaskets ready to fit the rocker box to the head, yes it is a pain but the pain eases the more times you do it *countdown*

Offline hdawson

  • A's Good Friend
  • ***
  • Join Date: Feb 2016
  • Posts: 108
  • Karma: 0
Re: A10 head gasket breakin
« Reply #13 on: 07.05. 2020 11:04 »
Couldn’t agree more.
 The old pushrod fitment drama.
I used to dread the job but after having to get the ‘box off and on half a dozen times a while ago to fix some long forgotten issue I managed to get it down pat.
Practice makes perfect .
Cheers

61 BSA Super Rocket (cafe).
51 Matchless G9 Clubman.
81 Suzuki GSX 750 ES.
02 Triumph Sprint.

Online BigJim

  • Valued Contributor
  • ****
  • Join Date: Aug 2018
  • Posts: 435
  • Karma: 1
  • Bristol. UK
Re: A10 head gasket breakin
« Reply #14 on: 07.05. 2020 18:09 »
Yep the welders clamp that was recommended on this forum, fits between the fins, really makes a difference!
Jamie,  Supporter of Distinguished Gentleman's Ride