Engine knock at start up


Information and questions on GL1200 Goldwings (1984-1987)
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JOLLY
Posts: 22
Joined: Tue Aug 22, 2017 9:23 pm
Location: Bonham, Texas 75418
Motorcycle: 1986 GL1200A Aspencade

Engine knock at start up

Post by JOLLY »



I have a 1986 gl1200A. At first start up after over night sitting. The engine after starting has a knock, knock, knock, knock sound that gets ones attention. I can turn the off/on switch to off and spen the engine over 5,6,7 times and then start the engine and it wont do it. Just started doing this the last couple of months. Never done this before. Note: My bike runs great after that. WHAT could be going wrong?? Any help or ideas PLEASE......



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Rambozo
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Motorcycle: 1992 GL1500 Aspencade

Re: Engine knock at start up

Post by Rambozo »

Put on a mechanical oil pressure gauge and see what you have during startup.

JOLLY
Posts: 22
Joined: Tue Aug 22, 2017 9:23 pm
Location: Bonham, Texas 75418
Motorcycle: 1986 GL1200A Aspencade

Re: Engine knock at start up

Post by JOLLY »

It acts like the oil pump drains over night.

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Rambozo
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Motorcycle: 1992 GL1500 Aspencade

Re: Engine knock at start up

Post by Rambozo »

Yes, but it should only take a few seconds to build oil pressure. Also normal bearing clearances will not knock just from startup. A mechanical gauge will tell you how long and what pressure you have. That will tell you something about the bearing clearances. You might not like the answer. But if you still have good oil pressure at a hot idle, you can probably live with the knock for years, especially if you do the kill switch routine for cold starts.

JOLLY
Posts: 22
Joined: Tue Aug 22, 2017 9:23 pm
Location: Bonham, Texas 75418
Motorcycle: 1986 GL1200A Aspencade

Re: Engine knock at start up

Post by JOLLY »

I agree with you. I'll get the gauge and get back with you/everyone.

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DenverWinger
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1980 GL1100 STD Vetter (2005-)
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1983 Trav-Lite Camper (2010-)
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1972 CL350 (1980-1988) sold
1978 Suzuki GS550 (1985-2005) sold
1977 GL1000 (2002-2006) sold

Re: Engine knock at start up

Post by DenverWinger »

My 1100 has had this start-up knock ever since I got it back in '05...... Goes away as soon as the oil pressure comes up and the oil light goes off. It's a little louder now at start-up than it was when I got it, but that was 15 years and more than 55,000 miles ago, including three cross-country trips, two-up pulling fully loaded camper trailer. Over 100,000 miles on it now.

You can hear a very slight knock at certain RPMs and load conditions going down the road.

I figure it's a sloppy piston wrist pin. Can't be a rod or main bearing knock, that would have catastrophically failed many many years ago. Have also considered sloppy cam bearings as the noise comes from the right side, but I actually doubt that too. S'pose I could get a stethoscope from Harbor Freight and check, though.
♫ 99 Little Bugs in the Code, ♪
♪ 99 Bugs in the Code. ♫ :(
♫ Take one down, Patch it around, ♪
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JOLLY
Posts: 22
Joined: Tue Aug 22, 2017 9:23 pm
Location: Bonham, Texas 75418
Motorcycle: 1986 GL1200A Aspencade

Re: Engine knock at start up

Post by JOLLY »

Mine too sounds like it comes from the right side. Question? I replaced the water pump about a year ago. Could the oil O rings inside the front cover be leaking causing the oil to drain out of the oil pump??

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roadwanderer2
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Motorcycle: previously owned 83 GL1100A aspencade traded for a motorhome, 1981 honda GL500i silverwing interstate, 1974 yamaha xs400, 1974 Honda cb450 twin cam, 1983 honda vt30, 1982 honda 700 shadow, 1972 cb750four, and my first bike, a brand new 1982 honda CM400e. now own-1986 GL1200 aspencade SEi
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Re: Engine knock at start up

Post by roadwanderer2 »

When you shut your bike down for an overnight "rest", do you put it on the side stand or on the center stand. Sometimes, more so than not, leaving these older wings on the side stand overnight tends to have the oil leak down onto the left side of the block, also causing some slight smoking upon startup.

Try putting your bike on the center stand when your finished riding it for the day and see what happens when you start it up the next time you go for a ride.

Stuart, a.k.a roadwanderer2.

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julimike54
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Location: Euless, Texas
Motorcycle: 1986 GL1200A original owner
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Re: Engine knock at start up

Post by julimike54 »

Oil filter draining down? Wrong one or missing a part in the assembly? Carbs not synched? :?:
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Maz
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Re: Engine knock at start up

Post by Maz »

JOLLY wrote:
Thu Nov 14, 2019 11:16 pm
I have a 1986 gl1200A. At first start up after over night sitting. The engine after starting has a knock, knock, knock, knock sound that gets ones attention. I can turn the off/on switch to off and spen the engine over 5,6,7 times and then start the engine and it wont do it. Just started doing this the last couple of months. Never done this before. Note: My bike runs great after that. WHAT could be going wrong?? Any help or ideas PLEASE......
Are you sure it's actually firing on all 4 cylinders when it's knocking? These engines sound very knocky when idling on less than 4.
Maz


Ironically, Common Sense is the LEAST common of all senses!

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