Head Gasket Leak Near Left Exh

MS850 · Apr 29, 2016

My MK3 Just developed a head gasket leak in front left just to the right of exhaust port. The nut from underneath was not tight. It was loose on both re-torques. I re-torqued again, I suspect the stud may be pulling out of the head.

Danno · Apr 29, 2016

Sounds like it. Better to get it apart and repair it than to run it and chance burning a valve.

MS850 · Apr 30, 2016

Danno said:
Sounds like it. Better to get it apart and repair it than to run it and chance burning a valve.

Thanks for getting back, Im afraid so. Ill get the head off, Ive got a call into my machinist on a time line to get the repair done.

**A cool thing is Karl Engellenner the mechanic/machinist has a Harley Aermacchi that Dave Roper rides.(the first American ever to win an Isle of Man TT, I believe on G50 Matchless)

drp · Apr 30, 2016

Had mine done by Jim Comstock. He did a great job

Dave

Holmeslice · Apr 30, 2016

MS850 said:
.... Ive got a call into my machinist on a time line to get the repair done.

**A cool thing is Karl Engellenner the mechanic/machinist has a Harley Aermacchi that Dave Roper rides.(the first American ever to win an Isle of Man TT, I believe on G50 Matchless)

Slight correction - Karl is partnered with Mike Bungay with the Aermacchi/HD Sprints (there are 2 in their team). Bungay owns the bike Roper rides. Karl's bike is ridden by Walt Fulton - Ex factory Harley Rider (beat Cal Rayborn!), as well as Suzuki and Kawasaki factory rider.
I just spent the last 3 days pitted with Karl and Bungay, Roper and Walt Fulton, racing at Sears Point. The best folks in town!

And yes, Karl is a wizard with the motors. You are in good hands.

MS850 · Apr 30, 2016

Holmeslice said:
MS850 said:

.... Ive got a call into my machinist on a time line to get the repair done.

**A cool thing is Karl Engellenner the mechanic/machinist has a Harley Aermacchi that Dave Roper rides.(the first American ever to win an Isle of Man TT, I believe on G50 Matchless)

Click to expand...

Slight correction - Karl is partnered with Mike Bungay with the Aermacchi/HD Sprints (there are 2 in their team). Bungay owns the bike Roper rides. Karl's bike is ridden by Walt Fulton - Ex factory Harley Rider (beat Cal Rayborn!), as well as Suzuki and Kawasaki factory rider.
I just spent the last 3 days pitted with Karl and Bungay, Roper and Walt Fulton, racing at Sears Point. The best folks in town!

And yes, Karl is a wizard with the motors. You are in good hands.

Opps sorry for the miis quote, my mistake.
Yes Karl is great a machinist.

Holmeslice · May 1, 2016

MS850 said:
Opps sorry for the miis quote, my mistake.
Yes Karl is great a machinist.

You know, come to think of it we're both right...
Although Bungay owns the bike Roper rides, Karl did the motor. Proof in the pudding there. He does amazing head work. You're in good hands, Mark.

MS850 · May 1, 2016

Holmeslice said:
MS850 said:

Opps sorry for the miis quote, my mistake.
Yes Karl is great a machinist.

Click to expand...

You know, come to think of it we're both right...
Although Bungay owns the bike Roper rides, Karl did the motor. Proof in the pudding there. He does amazing head work. You're in good hands, Mark.

Yeah, Im sure you know he works out of his garage, quit full time business awhile back. A lot of nice equipment, the automatic seat grinder (I think its a Serdi is impressive)

MS850 · May 2, 2016

hello again.
the three studs going into the head are , 3/8 x 26 x 20, 20tpi into the head. Is this a witworth pitch angle 50-deg or an american pitch 60deg.(i may may backwards)
And if I use and american studs what do i use for the short nut and long nut in the front by the exhaust port.
#18 nut and #20, #17-stud

L.A.B. · May 2, 2016

MS850 said:
the three studs going into the head are , 3/8 x 26 x 20, 20tpi into the head. Is this a witworth pitch angle 50-deg or an american pitch 60deg.(i may may backwards)

The 3/8 x 20 into the head is BSF, so is 55 degree thread.

http://www.britishfasteners.com/threads/bsf.html

head-stud-repair-options-t18848.html
head-studs-the-real-problem-t21549-15.html

[video]https://youtu.be/YXu4dVBfUBU[/video]

Nater_Potater · May 2, 2016

'Just went through this myself while in the process of having Jim Comstock repair the exhaust port threads; Jim drilled and tapped the three holes for 3/8-18 Helicoils, and I D&T'd the two front deep nuts for 3/8-24 Helicoils. At that point, easily-obtainable transition studs were installed in all three holes. The big advantage that gives you is the ability to use a small 12-point hardened nut on the rear stud. 'Much easier to get at for proper torquing...

Nathan

MS850 · May 2, 2016

Thats for info.
I decided to by the CNW head stud/bolt kit. The studs in question will be american threads, 3/8 – 16 x 3/8 – 24, includes everything for the top-end.

Also take a look at the cylinder walls, about 1k miles since bore. doesnt smoke, runs great.

MS850 · May 3, 2016

Got heli-coils in

MS850 · May 16, 2016

I got the head back on and running,
I ran engine until warm on lift with fans, cooled down and re-torqued the next morning, drove the next day about 50 miles, re-torqued the next morning.
I've read most procedures on re-torquing and there seems to be several methods. I'm going to re-torque and 300 miles, and if they're tight I think that will be it for re-torquing.

Nater_Potater · May 16, 2016

MS850 said:
I'm going to re-torque and 300 miles, and if they're tight I think that will be it for re-torquing.

'Sounds about right. It seems to initially be more of a heat cycle thing, rather than how far it's gone. I noticed mine needing a re-torque after the first full-on heat cycle, a very slight tweek after the second, then none since. I have to keep checking to see that there's oil in the tank, as my side covers are now oil-free. :mrgreen: WTH?

Nathan

MS850 · May 16, 2016

Nater_Potater said:
MS850 said:

I'm going to re-torque and 300 miles, and if they're tight I think that will be it for re-torquing.

Click to expand...

'Sounds about right. It seems to initially be more of a heat cycle thing, rather than how far it's gone. I noticed mine needing a re-torque after the first full-on heat cycle, a very slight tweek after the second, then none since. I have to keep checking to see that there's oil in the tank, as my side covers are now oil-free. :mrgreen: WTH?

Nathan

Thanks good to know on your re-torque,
The bike is dry right now also, the last leak I chased down was what I thought was the alternator wire grommet, ended up being the starter o-ring. Hopefully it stays dry for awhile, but I plan leaving the comfort of the garage. Feel the fear and do it anyway..... 8)

Fast Eddie · May 17, 2016

I was amazed at how many times I had to torque my head down after its rebuild, and by how much.

Does anybody know what the factory / dealers did when these were new? There is no way that they could possibly have done it the way we do it today...

On my recent top end rebuild, I over torqued by 5 ft lbs as recommended to me by Tony Smith. I'll let y'all know how this works out.

comnoz · May 17, 2016

Fast Eddie said:
I was amazed at how many times I had to torque my head down after its rebuild, and by how much.

Does anybody know what the factory / dealers did when these were new? There is no way that they could possibly have done it the way we do it today...

Well I don't know, I remember my dealer back in the 70's telling me to "make sure and keep those head bolts tight"

I retorque, or at least check them after every major road trip. They seem to settle down after 8 or 10 thousand miles. Jim

batrider · May 17, 2016

Fast Eddie said:
I was amazed at how many times I had to torque my head down after its rebuild, and by how much.

Does anybody know what the factory / dealers did when these were new? There is no way that they could possibly have done it the way we do it today...

On my recent top end rebuild, I over torqued by 5 ft lbs as recommended to me by Tony Smith. I'll let y'all know how this works out.

I bought mine new. The dealer was supposed to do it at the first service at 500 miles. Then it started leaking after getting some miles (5000) on it and it was time to replace the head gasket.

Last time, I retorqued mine at 5, 50, 100, 250, 500, 1000 and 2000 miles. A little nutty maybe.

Should be stone cold and one by one loosen it before retorquing. Adjust valve clearance afterwards. On a 750 with roadster tank you can do it without removing the tank so it's no big deal. Don't know how the 850 is.

I don't have the thread inserts so always did it to spec. Especially the 5/16 nuts in the front. If you add 5 ft-lbs to everything it will be larger percent increase for these two. I don't like that idea at all but I'm a nobody.

Russ

MS850 · May 17, 2016

Well I spoke too soon, rode to work today and found a oil leak coming nuts #9 and 10.
SOB, :evil:

Head Gasket Leak Near Left Exh

MS850

Danno

MS850

drp

Holmeslice

MS850

Holmeslice

MS850

MS850

Attachments

L.A.B.

Moderator

Nater_Potater

MS850

MS850

MS850

Nater_Potater

MS850

Fast Eddie

comnoz

batrider

MS850

Similar threads