Need advice about running on three cylinders for 84 wing


Information and questions on GL1200 Goldwings (1984-1987)
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tombyers
Posts: 14
Joined: Fri Dec 16, 2011 7:43 pm
Location: fort myers fl
Motorcycle: 1984 GL 1200

Need advice about running on three cylinders for 84 wing

Postby tombyers » Wed May 30, 2012 8:45 pm



Today I put the carburetors back on the motorcycle and started it up. Like always my number four cylinder was way different then the others on the vacuum gauges. So I did a compression test again. It came out 150 on #1 , 90 on #2, 130 on #3 and 50 on #4. So I got to thinking I should try to run the motorcycle on three cylinders, #1, #2 and #3. I could take the carbs off again and plug up the gasoline intake by putting epoxy in the hole of the float jet plug. But then what would I do about the spark plug sparking? Just leave it in there sparking away? I disconnected the cable to the #4 plug and there was no difference in the motorcycle idle or revving. Yes the cable is good and the spark plug does spark.



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virgilmobile
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Motorcycle: 1988 GL1500 I
Previously owned
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84 GL 1200 I

Re: Need advice about running on three cylinders for 84 wing

Postby virgilmobile » Wed May 30, 2012 9:50 pm

The cylinder will not fire with 50 psi.It's just too low.
Yes there would be a problem.
Sooner or later,if you just drive it the way it is some fuel will pass unburnt into the exhaust and ignite in there.
After checking valve clearance and verifying the timing belt is spot on ,you do a dry/wet compression test then pull the head for a rebuild to restore the compression.(assuming the rings pass the dry/wet test).
If you want a 3 cylinder bike,you need to cut the fuel in that carb.Wedge the float shut is the easiest.
Leave the spark plug in the hole.

You will have a 30% loss in power.

Your engine sounds like it sat up for a long time like my old 1100.When I tore it down,I only found it needed the valves lapped and the stems cleaned.They were sticking and one valve didn't seal real good.Just a head job brought it back to 155 across the board.I think I spent a couple of weekends and about $200 for all the gaskets and material to DIY.
You could see a burnt valve/bent valve,corrosion,blown head gasket,ets

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seabee_
Posts: 494
Joined: Sun May 29, 2011 8:17 pm
Location: sterling heights, mi
Motorcycle: 1985 Honda Goldwing GL1200
117k miles
1977 Kawasaki kz400
1978 Suzuki GSXr750
1980 Kawasaki GPZ400
1975 Honda CB360T

Re: Need advice about running on three cylinders for 84 wing

Postby seabee_ » Wed May 30, 2012 11:55 pm

You should also do a wet test for compression. Squirt some oil in the cylinders and do compresion test again. ALSO, make sure all spark plugs are removed and have throttle wide open during test to get accurate consistant readings. It sounds like the rings COULD be stuck from sitting too long, but maybe not. If they're stuck, you can spray PB Blaster in the cylinders, let it sit a bit and ride the bike awhile to loosen the rings. Then do another compression test to see if it helped. Just a suggestion.
Paul
CE1 Navy Seabees/RET
1981 to 2002
ASE Mechanic

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seabee_
Posts: 494
Joined: Sun May 29, 2011 8:17 pm
Location: sterling heights, mi
Motorcycle: 1985 Honda Goldwing GL1200
117k miles
1977 Kawasaki kz400
1978 Suzuki GSXr750
1980 Kawasaki GPZ400
1975 Honda CB360T

Re: Need advice about running on three cylinders for 84 wing

Postby seabee_ » Wed May 30, 2012 11:58 pm

Just an add on to above post, hit the starter before putting plugs back in to be sure there's not too much oil it hydro locks.
Paul
CE1 Navy Seabees/RET
1981 to 2002
ASE Mechanic

tombyers
Posts: 14
Joined: Fri Dec 16, 2011 7:43 pm
Location: fort myers fl
Motorcycle: 1984 GL 1200

Re: Need advice about running on three cylinders for 84 wing

Postby tombyers » Thu May 31, 2012 7:48 pm

I continued to tinker with carb synchro screws and three test drives and am happy with results of third carb overhaul. No loud farting noises at all during deceleration. What a relief! Runs about as good as could be expected for having a bad cylinder. Today I did spray some oil in bad cylinder spark plug hole and rode it and retested the compression and only got 40psi compression. Then I hooked the spark plug wires up on the other three cylinders and it just bounced a little off of zero while the motorcycle idled. I really like the idea of taking the head of the engine off on that side and redoing the valves. I will have to study my manual and online parts. Thank you for your advice! On another issue I checked my firing order and it was from left to right 2341 the clymer manual says "There are two ignition coils; one fires the plugs for the No. 1 and No.3 cylinders and the other fires the plugs for the No.2 and No. 4 cylinders". Well my spark plug cables wouldn't reach to try it that way so I hooked them up according to how VirgilMobile said to do it (4321) and they worked good. I know I should take off the carbs again and block the gas flow to the bad cylinder but instead I am going to remove the fairing (not enough clearance to remove lower fork allen bolts with fairing in place) and jack the front wheel off the ground with a car jack and remove the front wheel and forks and sand the itty bitty teeny tiny pits off the left fork and change the oil seal as it is shot and the front disk rotor is covered in fork oil (not good), so that is my next project.

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seabee_
Posts: 494
Joined: Sun May 29, 2011 8:17 pm
Location: sterling heights, mi
Motorcycle: 1985 Honda Goldwing GL1200
117k miles
1977 Kawasaki kz400
1978 Suzuki GSXr750
1980 Kawasaki GPZ400
1975 Honda CB360T

Re: Need advice about running on three cylinders for 84 wing

Postby seabee_ » Thu May 31, 2012 10:51 pm

If the bike has been sitting for any length of time and the rings are indeed 'stuck' it will take awhile to free them up. It will just take some more riding to do it. Hopefully they will free up for you before tearing into the motor. Give it a few days of riding and see if the compression starts coming back up. You just have to remember to "fog" the cylinders after you park it for the night and the motor cools off and allow the PB Blaster to work into the rings. Try the easy things first. Sometimes they work out.


Paul
CE1 Navy Seabees/RET
1981 to 2002
ASE Mechanic


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