Vacuum blowing not sucking


Information and questions on GL1200 Goldwings (1984-1987)
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seasicksid
Posts: 38
Joined: Tue Oct 08, 2013 5:11 pm
Location: Essex, England, United Kingdom
Motorcycle: 1984 GL1200 Interstate
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Vacuum blowing not sucking

Postby seasicksid » Fri Dec 27, 2013 10:20 am



OK. I did say I was new to Goldwings...

I've just replaced the valve guide seals, Rebuilt the carbs and replaced associated gaskets and belts. Set the valve timing to "T" mark. Turn on the fuel. Connected the battery and turned her over. Not even a pop or a bang, so started investigating. Plugs dry so tried fuel in the phlenum. No change. Bought a can of the last resort eazystart. No change. Got good spark, and compression. I removed the vacuum screws on the intake manifolds and to my surprise they were blowing strong compression out rather than sucking air in. I checked the valve seats and made sure they were air tight when the heads were off, so its not them.
Is it possible to have the valve timing 180 degrees out?

Scratching my head to baldness.



rzaugg
Posts: 88
Joined: Tue Oct 01, 2013 10:04 pm
Location: Cedar Rapids, Ia
Motorcycle: 1984 GL1200 Aspencade
1989 GL1500 Aspencade

Re: Vacuum blowing not sucking

Postby rzaugg » Fri Dec 27, 2013 1:19 pm

If you had the crankshaft at TDC of #1 cylinder, and I am assuming you did from the way you wrote it, then the camshafts are what decides what is the compression stroke and what is the exhaust stroke. You can"t really have the cams 180 off because for one full revolution of the crankshaft, the camshafts turn 1/2 of a revolution. When you turned it over by hand, did the marks line up again with the marks after two full turns? If all that is verified good, then my next question would be "How far did you tear it down?" Mainly wondering if you took the camshafts themselves out of the heads, and is it possible that you put them in the wrong side when reassembling. They are different part numbers, although I don't know if switching them would cause this or not.
Pull the right side valve cover off and turn the engine over by hand from the crankshaft. Will be easier if you pull the spark plugs. Shortly after 1/2 turn, the exhaust valve should begin to open. 1/2 turn later, the intake valve should start to open and the exhaust valve should close. 1/2 turn after that, the intake valve should close. And finally for the last 1/2 turn, there should be no activity in the valvetrain. Mind you, that this is only for the #1 cyl. The sequence will be the same for all cylinders, but from TDC #1, they will start from a different step of the sequence. I really hope that this helps. Keep me up to date on what you find.

P.S. If you didn't take the camshafts out, I will have to think about this one for awhile.

Rick

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seasicksid
Posts: 38
Joined: Tue Oct 08, 2013 5:11 pm
Location: Essex, England, United Kingdom
Motorcycle: 1984 GL1200 Interstate
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Re: Vacuum blowing not sucking

Postby seasicksid » Sat Dec 28, 2013 5:05 am

Well would you believe it ??? I'm guessing you would.
Took the plugs out, valve covers off then set engine to "T" mark. Slid a probe into No 1 cylinder and low and behold the piston was at the bottom of the stroke. Did the same to No3 and she was at TDC. WHAT A PLONKER !!. I'd got my crackers in a twist and timed it to No3.
I removed the belts and re set the timing to No1. Turned it by hand a few times and re checked. Put everything back together and pushed the button......
First touch she fired up and purred like a Tiger. How lucky was that? Gonna sync the carbs today. One happy bunny.


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