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Post by liffy16 on Sept 6, 2021 8:33:26 GMT 1
Head gasket went on my 350ypvs so got genuine gasket cleaned both faces torqued head down run heat cycle without coolant re torqued added coolant. Road test and water coming out of header tank 😞
In desperation put some rad weld in and road test leak cured ,anyone else done this ?
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Post by midlifecrisisrd on Sept 6, 2021 8:44:47 GMT 1
Nooooooooooo!
Radweld is crap. Even the leaking head gasket repair stuff ain't advisable
When changing a head gasket you really need to fit new base gaskets, fit the barrel bolts finger tight, fit and torque the head then tighten the barrel base nuts
Steve
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Post by reedvalve on Sept 6, 2021 16:45:33 GMT 1
Radweld is going to reduce the radiator cooling efficiency, not nice stuff! If the gasket isn't sealing then there must be a problem somewhere:
1. Are the lengths of the barrels the same and gasket faces parallel, one may be taller than the other, small differences can be worked around as Steve says by not fully tightening the barrel base bolts until the head bolts are fully tight. I once had a 250LC set that were 1mm different, had to put them in a lathe to correct the long one by taking a bit of the base. Don't assume they are the same.
2. Are the head and barrel gasket faces actually flat, you can lap the head and the barrel faces on a flat glass plate or similar with wet & dry taped to it.
Chris
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Post by liffy16 on Sept 6, 2021 19:59:22 GMT 1
Radweld is going to reduce the radiator cooling efficiency, not nice stuff! If the gasket isn't sealing then there must be a problem somewhere: 1. Are the lengths of the barrels the same and gasket faces parallel, one may be taller than the other, small differences can be worked around as Steve says by not fully tightening the barrel base bolts until the head bolts are fully tight. I once had a 250LC set that were 1mm different, had to put them in a lathe to correct the long one by taking a bit of the base. Don't assume they are the same. 2. Are the head and barrel gasket faces actually flat, you can lap the head and the barrel faces on a flat glass plate or similar with wet & dry taped to it. Chris Did all the above 2years ago when I rebuilt engine checked barrel heights at work with digital height gauge and checked head on granite marking out table |
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Post by reedvalve on Sept 6, 2021 20:35:54 GMT 1
Radweld is going to reduce the radiator cooling efficiency, not nice stuff! If the gasket isn't sealing then there must be a problem somewhere: 1. Are the lengths of the barrels the same and gasket faces parallel, one may be taller than the other, small differences can be worked around as Steve says by not fully tightening the barrel base bolts until the head bolts are fully tight. I once had a 250LC set that were 1mm different, had to put them in a lathe to correct the long one by taking a bit of the base. Don't assume they are the same. 2. Are the head and barrel gasket faces actually flat, you can lap the head and the barrel faces on a flat glass plate or similar with wet & dry taped to it. Chris Did all the above 2years ago when I rebuilt engine checked barrel heights at work with digital height gauge and checked head on granite marking out table Huum, other than bad scratches which I'm sure you would have noticed the other thing is a crack somewhere that opens with the heat, just enough to cause the issue and which the Radweld has blocked, or silly question, is your torque wrench OK and possibly reading a bit low? |
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Post by bare on Sept 6, 2021 23:46:53 GMT 1
Why run a 'heat cycle' without Coolant ??
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Post by JonW on Sept 7, 2021 1:32:33 GMT 1
Why run a 'heat cycle' without Coolant ?? I never understand that either, but people do this stuff. I think its an old wives tale type thing, people read or are told about doing it and think its what they need to do. Yamaha never did this with their engines. No manual (haynes or OEM) says its a good idea to do this. So, why do it? This is an engine that requires coolant, thats what LC means isnt it?! As for rad weld... thats a 'no' from me as well. The cooling on these engines wont thank you for having that crap floating around inside. The stuff is a useful as a desperation measure for getting you home, but its not a real fix.  I'd strip this apart and build it again with new OEM top and base gaskets, I'd add some copper spray on the top one to be sure and check over the cyls again to be sure there are no marks/scratches/cracks etc. |
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Post by liffy16 on Sept 7, 2021 15:22:48 GMT 1
Rode to work this morning 10mile not used any coolant but still not running right as there is still an underlying electrical fault as it completely stopped on me about 4 weeks ago ,powervalve has started doing cleaning cycle again after it stopped working all together!Back to the drawing board will do head, barrels again and start looking at loom ,stator this was such a great running bike for years and always my go to bike for a reliable ride out ,sadly not anymore
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Post by JonW on Sept 8, 2021 0:29:41 GMT 1
redoing the cleaning cycle could be as simple as a power issue, could be the ignition or a wire/connector etc.
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