cylinder head problems!!! need help!!!


Information and questions on GL1200 Goldwings (1984-1987)
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wingsfan98
Posts: 8
Joined: Thu Mar 15, 2012 6:19 pm
Location: Pontiac, Michigan
Motorcycle: 1984 gl1200a

cylinder head problems!!! need help!!!

Postby wingsfan98 » Sun Sep 23, 2012 7:43 pm



i recently started to rebuild my dads 1984 GL1200 Aspencade... he and I had it running and after years of the previous owners wear and tear and improper timing it put one of the valves through the piston head. we finished fixing all this and we replaced the pistons and put a new left side cylinder head on. we had been told that the 1985 GL1200 Aspencade and the 1984 GL1200 aspencades cylinder heads and the entire engines were identical. However the people who told us this were wrong as I am discovering that the 1984 model has what is called a secondary air supply valve that fits under the seal between the head and the port that goes to the carburetor that is not on the 1985 models... has anyone else run into this problem? also are these secondary air supply valves necessary? is there a way to machine this head down so as to make these fit or are they needed to make the engine run properly.



User avatar
firstwing85
Posts: 86
Joined: Mon Aug 15, 2011 11:33 am
Location: Aldergrove BC Canada
Motorcycle: 1985 GL1200 Limited Edition
1983 V65 Magna

Re: cylinder head problems!!! need help!!!

Postby firstwing85 » Tue Sep 25, 2012 2:13 am

I wish I could help with this one but I just don't have enough experience yet.
hopefully someone will come along for you soon.
Johan

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feetup
Posts: 100
Joined: Mon Jun 29, 2009 1:15 pm
Location: West Coast of Canada
Motorcycle: 84 GL 1200I
75 GL 1000 (in pieces)
'02 Gas Gas Trials
'56 Norton 600

Re: cylinder head problems!!! need help!!!

Postby feetup » Tue Sep 25, 2012 10:10 am

The idea behind the secondary air supply is the same limp thinking that put air pumps on the majority of autos in the early 80's.
I would call it a miss guided attempt to reduce emissions. The theory was that pumping or admitting fresh air into the hot exhaust gasses immediately as they left the cylinder would burn any unburned hydrocarbons and produce a cleaner exhaust.
I suppose they did this to some extent, but the reality was that they merely diluted the gasses so that the measurable parts per million of unburned hydrocarbons was reduced, therefore fooling the test equipment.
The bike will run just as well without it, although you will smell rich conditions on deceleration some times. You will have to plug off the feeder pipes on the head you do not connect, or the whole system if you wish. It takes it's air from the bottom of the plenum chamber, after the air cleaner so if you disconnect be sure that you plug things well. Also, you will have to leave the feeder pipes in place on the '84 head and plug them well since they are directly connected to the exhaust ports. I suppose if you have access to a lathe you could machine up some plugs to the same dimension as the feeder pipe ends.

wingsfan98
Posts: 8
Joined: Thu Mar 15, 2012 6:19 pm
Location: Pontiac, Michigan
Motorcycle: 1984 gl1200a

Re: cylinder head problems!!! need help!!!

Postby wingsfan98 » Tue Sep 25, 2012 11:45 am

Thanks Feetup,
That is what I thought when I cut up the old heads. It was a non necessary idea that just made the engine look more complicated.
I appreciate the feedback.

Do you think "Cold Steel" or "JB Weld" would be sufficient to do the plug?

wingsfan98

User avatar
feetup
Posts: 100
Joined: Mon Jun 29, 2009 1:15 pm
Location: West Coast of Canada
Motorcycle: 84 GL 1200I
75 GL 1000 (in pieces)
'02 Gas Gas Trials
'56 Norton 600

Re: cylinder head problems!!! need help!!!

Postby feetup » Tue Sep 25, 2012 12:10 pm

Yes, I think that would work well, if you were really careful that the surfaces you were applying it too were surgically clean. I would lean toward JB weld. I have had some wonderful success with it.
You might encounter issues having one head with and one head without but It would not surprise me at all if eliminating the system all together allowed you to run stock carb settings, and this system should not affect ignition settings at all. I'm not sure though if the US ignition mapping is the same as Non-US models.




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