[box]

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I have a 1500 gl the problem is that the engine has a knock in it. It only starts to knock when the engine gets a little warm after i have been driving it. Almost sounds like a main bearing but ive tried to listen for the sound and it almost sounds like it is coming from one of the heads. Also if i put it on the centre stand and let it warm up there is no sound. can anybody help me!

 

[leeatcp]

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Take the Longest Screwdriver put to your ear. touch all different area of the engine. What your are looking for is the loudest place, that will be area to look at for repairs.

Harbor freight has 2 different MECHANIC'S STETHOSCOPE, that you can buy, MillRat)

 

[rhughes]

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If the carbs are not synced it will knock. But if there is a problem in the crank bearings or rod bearings the knock will usually not go away it will only get worse.

 

[goldtop]

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the noise from carbs in need of a sync is there and fades under load. it tends to come from the rear portion of the engine. Oil sounds the most favored area to start. Change check type and change the filter. I guess that you noticed the noise at tickover on the side stand and when the bike is on centre gravity centres the oil. Under load and hot the oil is thinner and so will move back in the sump under acceleration. you don't mention mileage. remember they are good for at least 200,000 before major works

If the noise is getting worse then as above consider the bearings it might be worth a look under the rocker covers and see if the valve stem oil seals are shot on one cylinder. try the screw driver again and single out where the noise is loudest and try there.

 

[rhughes]

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How many miles on the clock?

 

[sprite123]

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Are you sure the knock isn't coming from the alternator, as mine did that when the rubber drive bushes became hardened. Gets better when the engine is realy warm and they soften. Worth a check. Steve

 

[Foosman(5)]

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If my engine gets really hot (not warm) I have noticed is a very slight knock that sounds like amain rod. And that is only at idle. My fans do not kick in and temp gets pretty high at +3/4 gauge.

I went through my motor at 24k to replace a piston and bearings were fine. I did not check rods or had them resized since the miles were low and did not look bad.This type of thinking has got me in trouble twice on automotive engines.

If yourknock is not too bad, you will have to live with it.It would be a true pain to replace bearings. If the knock is pretty bad, assuming it is a rod bearing, disconnect the spark plug wiring one-by-one to see if you could isolate.

Could be fuel detonation or pre-ignition as the engine gets hot.

 

[box]

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I have already used a stethescope all over the engine, and this noise is really hard to judge where it is coming from. Maybe head noise may be internal. The odometer says that it only has 115000 Kilometers and I dont think it is carbs because it runs real smooth. Also have a brand new coupling on the alternator and have ruled it out

 

[rayworx]

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Any chance the engine has been removed from the frame and engine work been done??? The reason I ask is I once saw a Honda CB350-4 cylinder that made a main bearing type of knock that turned out to be a dowel pin missing and the crankshaft end of the stator knocking on the housing. Sounded just like a bearing.

 

[box]

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I dont think the engine has ever been worked on. Also i am runing Golden spectro synthetic 10-40 motorcycle oil and emgo filter i was thinking of putting Amsoil synthetic 20-50 motorcycle oil in. And if this reduces the noise it would make sense that it is internal.

 

[Carter_s.]

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Hi,

Has the engine ever been out of the frame? The reason I am asking this question is because it mite be slightly loose or not totally tightened mounting or support bolts allowing the engine too ever so slightly to move causing the knocking noise that you are hearing. Go around all of the mounting bolts and the frame support ribs in the lower front. and make sure that all of these bolts are tight. The other thing that you might see is a very sleight and light rust color around a mounting bolt that is loose and chucking. It will look like a very light tan in color. Try to tighten all of the bolts before you start spending money on parts and Assoil and filter. Not a bad or wrong oil to use or go for but try the no cost and easy items first.

Please let me know if this has taken care of the problem.

Carter

 

[Rudy]

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Try Chevron DELO-400 15w-40 diesel rated and see if the problem persists.

 

[Mr. Fix it]

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Hi There Box.

I have a GL1500 with about 180,000 miles on the clock.

When I first got it, I changed the oil to 10w40 frm the PO that was using 20w50

A knock appeared about 20 miles into the oil change.

I went back to the 20w50 and the knock went away.. Go figure..:baffled:

So, that is what this engine runs, Castrol 20w50.

I personally would try a less expensive 20w50 oil before going staright to the AmsOil to see if the knock settles down.

If it does, go for the AmsOil next change!

 

[goldtop]

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Thats seems to be the consensus at the moment. There doesn't seem to be much from anyone that your problems are deep down. If the rumours about these engines are true then your is only half way through its life. A very comforting thought.

Get back on this thread if your problems don't get better after the oil change but without a clear area of where the noise is coming from we are all a but mistified.

Again as said before, hats off to those who help out over this medium without seeing the bike or hearing or smelling what you can.

 

[Foosman(5)]

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Could it be a "tick" and not a "knock".

If yes, there will be another set of responses. :dude:

 

[box]

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It is a definate knock. Thanks to everyone that responded will try some of the recomendations,but sadly it wont happen till spring. Right now we have 4 feet of snow thankyou again