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Discussion Starter · #1 ·
Hi guys.



I am pretty new at this so please bear with me if I miss protocol.



I recentley bought a 650e and was taken for a ride I think. When I checked the coolant in the plastic tank, it was OK. Rode the bike for about 40km home and half way the oil light came on. It got too hot I guess. After checking the bike again, I found that the radiator was dry. I filled it up with coolant (from the radiator cap) and went for a ride. Lo and behold checked the oil when I arrived back home, condensed milk, coolant in the oil. I have am now busy to replace the top gaskets, questions are these:



How can I know which cylinder blew a gasket? I have taken off the cylinder head covers and the left hand cover has a lot more "gumk" inside than the right.

What else can cause coolant to get into the oil apart from a head gasket going or a cracket or warped cylinder head?

Lastly, I removed the cam shaft holder (on the front of the engine) and I cannot get it back in. Is there a trick or something I am missing her? It came out easily enough.



Your assistance will be greatly appreciated. I bought this bike because I really love the lines (and it fits my age:)

so I would really like to get it going again.
 

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'84 CX650E that is evolving into a GL500
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You can sometimes figure out which head blew a gasket by looking at the spark plugs (if one has coolant on it you have the culprit) and sometimes by looking in the exhaust port. If you have removed the exhaust collector box and have separate left & right exhaust systems you can tell by which side the steam comes from.



There have been rare cases of someone blocking the water pump weep hole, usually because the mechanical seal in the pump had failed and they didn't know what the hole was for, and that allowed pressurized coolant to force its way past the camshaft oil seal.



IIRC, some force may be needed to get the the camshaft holder back in. I seem to recall using a deadblow hammer to persuade it back in after replacing the gasket (never use a metal hammer for jobs like this). The problem is caused by the pressure from the valve springs pushing on the camshaft and moving the end of it out of the centre of the opening.
 

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Discussion Starter · #4 ·
Thanks for the replies you guys. Iro the contaminant in the oil. There were no steam and the spark plugs showed nothing either. I have now removed the left hand cylinder head, the two top bolts were covered in contaminated oil when I removed them. They actually made a "slurping" sound when I took them out. The bottom two were OK. It was such a mess when I removed the head that I could not tell where the problem was, with my untrained eye that is. If I have to venture a guess it seems that the water blew outwards and into the cavity which accomodates the push rods. But as I've said that is merely a guess. The piston head shows no signs of oil or coolant neither does the water jacket. Should I just replace the gasket and hope for the best or should I remove the motor entirely and check the waterpump weep hole?
 

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'84 CX650E that is evolving into a GL500
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The waterpump weep hole can usually be checked with the engine in the frame. The hole is in the rear engine cover and it should be visible when you kneel beside the bike (on the left side) look up under the overhanging edge of the water pump cover. If you see anything that looks like a hole that has been plugged you may have found the problem. If you can see the hole and it looks open, try pushing a wire up the hole. If the wire goes in a couple of inches the hole isn't blocked. If the hole isn't blocked and you don't see coolant or oil running down the side of the engine below it the mechanical seal and the camshaft oil seal are not leaking.



Usually (but not always) when a head gasket fails it begins leaking between the combustion chamber (where the highest pressures occur) and the water jacket. If you catch it early enough you will find big bubbles in the coolant recovery tank (usually you can hear them). When this occurs, the spark plug will look really clean (it has been steam cleaned) when compared to the other side's plug. If left unattended this can sometimes lead to failure between the water jacket and the crankcase and lead to coolant being blown into the crankcase (via the pushrod opening) where it mixes with the oil.



Sometimes the gasket fails between the water jacket and the crankcase without failing between the combustion chamber and the water jacket. When that happens, coolant at 13 PSI (the normal system pressure - not as high as the pressure in the combustion chamber but higher than in the crankcase) is forced into the crankcase (via the pushrod opening) where it mixes with the oil.



Often the only way to determine which head gasket has failed is to take them out and examine the gaskets themselves.
 

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Discussion Starter · #7 ·
Thanks Bob. I'll have a look at that weep hole and I think, following your advice, that I'll remove the other head as well and replace both gaskets with OEM parts anyway.



Hi Shep. I did not find any pieces of metal in the oil when I drained it. I have also removed the oil filter, clutch cover and strainer tray, did'nt find any pieces.
 

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Thanks Bob. I'll have a look at that weep hole and I think, following your advice, that I'll remove the other head as well and replace both gaskets with OEM parts anyway.



Hi Shep. I did not find any pieces of metal in the oil when I drained it. I have also removed the oil filter, clutch cover and strainer tray, did'nt find any pieces.




That's good news.
 

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Discussion Starter · #9 ·
Hi guys. I'm trying to find the weep hole on that water pump. I'm looking at it fron the left hand side of the bike, but don't see anything. Should I first remove the chrome waterpipe fron the pump? Or maybe I'm looking in the wrong place?
 

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2021 Benelli Leoncino Trail - 2021 CSC SG400 - 2017 SSR Buccaneer 250i - Several CX project bikes
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Hi guys. I'm trying to find the weep hole on that water pump. I'm looking at it fron the left hand side of the bike, but don't see anything. Should I first remove the chrome waterpipe fron the pump? Or maybe I'm looking in the wrong place?


Last time this happened to me it was a failure of the water pump seal and a blocked weep hole. You'll need a mirror, like a dental mirror, to even see teh weep hole.



If it is the camshaft oil seal that was compromised, you'll have to pull the engine to replace it. And the longer you wait the better the chance that the camshaft will rust. If that happens you're boned, an oil seal won't seal to a rusty camshaft surface.



Charles.
 
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