tazz229 Posted September 17, 2012 Report Share Posted September 17, 2012 (edited) Ok I've seen various topics and such like about overheating causing cumbustion pressure to force its way passed the O rings, and in turn blow the water pump seal. This I understand completely makes perfect sense! I've had the head off and both the O rings look fine. As it is at the moment I can't see the WP seal because the damn bolts are seized and need drilled out but I'll get to that... So when my rectifier packed up my bike did overheat I limped home as fast as I could in as high a gear as I could to get max airflow through the rad with the least amount of revs. However I noticed today that my oil was milk! So an educated guess tells me that's what's happened to me. So my questions are: 1. If the O rings were damaged would it be visible? 2. If the WP seal was damaged would it be visible without stripping it? 3. Can the WP seal be replaced without removing the engine casing? Much appreciation for any input Oh and what's the difference in the 0.1 0.3 and 0.5mm gaskets? Don't say thickness I know that does it really make much difference between the three? Edited September 17, 2012 by tazz229 Quote Link to comment Share on other sites More sharing options...
sting32 Posted September 17, 2012 Report Share Posted September 17, 2012 To be honest, on a Gas Gas pro models, the seal that is behind the water-pump, is a "wear" item, the seal has a tendency to actually wear a groove on the pump shaft, where the pump shaft goes through the seal, which then causes the seal to be easier to "breach" if you get my drift. it takes about $60 or $80 US dollars, to get a new water-pump seal kit in the USA at least. Which replaces the little shaft, the seal, and I think the impeller. you have to make dang sure you put the seal in the right way! and, when you put it back together, you need to put a tiny little bit of grease on that seal, when you push the shaft through that seal, the seal has kind of 2 lips to it. don't overdo it, but a tiny amount, seems to let the seal last longer, I believe. (jury is out on this if you dont use any grease, that is fine too. BTW, I happen to use the same seal grease I bought to assemble the front fork seals, on that WP seal. Fork Seals, they SHOULD get greased when you do those, or they fail prematurely as well, I have been told. (disclaimer) - All of that information above is what I do, you might find out different ideas from other people. Or I could be doing it wrong, lol. 1 Quote Link to comment Share on other sites More sharing options...
lineaway Posted September 18, 2012 Report Share Posted September 18, 2012 You have to remove the case. Then remove the snap ring on the plastic gear. The gear then comes off the shaft, it looks like the pin holds it,but it comes right off. There is another snap ring between the seal and the bearing. Fairly easy job if you have snap ring pliers.Check the shaft for wear. If it is not too bad polish up the shaft before assembly and grease the seal. Quote Link to comment Share on other sites More sharing options...
tazz229 Posted September 18, 2012 Author Report Share Posted September 18, 2012 You have to remove the case. Then remove the snap ring on the plastic gear. The gear then comes off the shaft, it looks like the pin holds it,but it comes right off. There is another snap ring between the seal and the bearing. Fairly easy job if you have snap ring pliers.Check the shaft for wear. If it is not too bad polish up the shaft before assembly and grease the seal. Cool no probs thank you kindly Quote Link to comment Share on other sites More sharing options...
tankygsy Posted September 18, 2012 Report Share Posted September 18, 2012 Questions 1 & 2: not always, sometimes in fact most of the time seals look visually ok but pass fluids. Question 3: you must get the bolts out to change the seal. Have you tried an impact driver on the bolts after soaking them in loads of wd? Even the most stubborn of bolts will come out this way if there is a bit of head gripping ability left. Quote Link to comment Share on other sites More sharing options...
tazz229 Posted September 18, 2012 Author Report Share Posted September 18, 2012 I'll replace the O ring anyway then! I kinda dismissed the impact driver idea because the casings are so brittle and I'm the sort of person that will hit it too hard and smash a hole in it! I really don't trust myself with it. I have a habit of breaking things that cost a fortune to replace lol I'll drill them out trust me it's safer all round! Quote Link to comment Share on other sites More sharing options...
sting32 Posted September 18, 2012 Report Share Posted September 18, 2012 I'll replace the O ring anyway then! I kinda dismissed the impact driver idea because the casings are so brittle and I'm the sort of person that will hit it too hard and smash a hole in it! I really don't trust myself with it. I have a habit of breaking things that cost a fortune to replace lol I'll drill them out trust me it's safer all round! Well, Tazz, the phraze "get a bigger hammer" definitely doesnt apply to you! you need to "smack" the impact (hammer driven screwdriver like impact wrench) not sledgehammer or SLAM on them. the orings, when you put it back together, use a tiny bit of greas to hold them in place, what happens is you turn head over and orings fall out of the grooves, the orings (if I recall correctly) will almost seem too big, but they do fit. usually 3 little dabs of grease (thick hard pasty type) will hold them while you let it down. The below the cylinder gaskets are adjustments to where the piston rises to in comparison to the head, called "squish" or something technical. there has to be a minimum clearance for the cylinder to the head. so color of gaskets also denotes the thickness. I think there are about 5 or 6 different thickness gaskets you can order when you need to. If your gaskets are good you can reuse them. soapy water can check for leaks when running. FWIW, my 08 had bad gasket at the base, I never really noticed it, except that the carb was finicky... Anyway, as it turned out, I felt it one day. I could feel it only because I had shorts on, which I hardly ever wear around bikes, that day... Quote Link to comment Share on other sites More sharing options...
tazz229 Posted September 18, 2012 Author Report Share Posted September 18, 2012 Well, Tazz, the phraze "get a bigger hammer" definitely doesnt apply to you! you need to "smack" the impact (hammer driven screwdriver like impact wrench) not sledgehammer or SLAM on them. the orings, when you put it back together, use a tiny bit of greas to hold them in place, what happens is you turn head over and orings fall out of the grooves, the orings (if I recall correctly) will almost seem too big, but they do fit. usually 3 little dabs of grease (thick hard pasty type) will hold them while you let it down. The below the cylinder gaskets are adjustments to where the piston rises to in comparison to the head, called "squish" or something technical. there has to be a minimum clearance for the cylinder to the head. so color of gaskets also denotes the thickness. I think there are about 5 or 6 different thickness gaskets you can order when you need to. If your gaskets are good you can reuse them. soapy water can check for leaks when running. FWIW, my 08 had bad gasket at the base, I never really noticed it, except that the carb was finicky... Anyway, as it turned out, I felt it one day. I could feel it only because I had shorts on, which I hardly ever wear around bikes, that day... Funny enough I watched Jims video on replacing them so should be fine there. I did have the head off last night and to be fair the O ring doesn't really look too round any more both sides are flattened if ya get what I mean. I've just ordered one so I'll get that fitted sharpish. I thought maybe by running it without the rad cap on I might of seen bubbles or a build up of pressure when I lightly covered the hole with my finger but there doesn't seem to be any. For the sake of £4 though I'll do it anyway. How they can justify £3.95 postage is a whole new topic!! Any idea what the different base gasket colors are in relation to size? Mines like a dark grey and very thin like paper! Quote Link to comment Share on other sites More sharing options...
tazz229 Posted September 18, 2012 Author Report Share Posted September 18, 2012 Is it ok to flush the gearbox with a bit of premix?? Quote Link to comment Share on other sites More sharing options...
tankygsy Posted September 18, 2012 Report Share Posted September 18, 2012 Why would you want to flush the gearbox with premix? Do you mean flush the crank and bearings etc? If so you don't really need to unless you have a serious build up of carbon in there. It will most likely be staind black inside the crank case but stains can be left alone as there really is nothing to gain. As for base gaskets don't just replace the one you have, and don't go by trying to match gasket colours, the one fitted now may not be the correct one to begin with. Best to take a squish measurement and see what base gasket you actually require. Quote Link to comment Share on other sites More sharing options...
tazz229 Posted September 18, 2012 Author Report Share Posted September 18, 2012 Because I've got milky oil mate and want to flush it. I drained it out and refilled with fresh but it seems there was still some "milk" left behind because it's tainted the fresh stuff. So wanted to give it a flush out like you would on a car with engine flush. Quote Link to comment Share on other sites More sharing options...
tankygsy Posted September 18, 2012 Report Share Posted September 18, 2012 By the way why do you want to replace the base gasket? You don't need to remove the cylinder head to change orings on the combustion chamber top cap... Quote Link to comment Share on other sites More sharing options...
tazz229 Posted September 18, 2012 Author Report Share Posted September 18, 2012 By the way why do you want to replace the base gasket? You don't need to remove the cylinder head to change orings on the combustion chamber top cap... Just because it doesn't hurt to have a full fresh set of top end gaskets that was all. For the price of it I figured I might as well while I had spanners in my hand so to speak. Quote Link to comment Share on other sites More sharing options...
jse Posted September 19, 2012 Report Share Posted September 19, 2012 As for base gaskets don't just replace the one you have, and don't go by trying to match gasket colours, the one fitted now may not be the correct one to begin with. Best to take a squish measurement and see what base gasket you actually require. Good advice. Use a piece of curved soft solder through the plug hole to measure and look for a squish clearance of at least 1mm (.039 in) and you should be o.k. As to the o-rings, grease the complete o-ring (and all o-rings) before installing and that will keep them from tearing or being cut. This allows the o-ring to move slightly and "settle" in the groove. A good example is the very thin o-ring on the Pro waterpump body, which will often be shaved in half if not greased (and the body pushed in square to the bore). Jon Quote Link to comment Share on other sites More sharing options...
tazz229 Posted September 19, 2012 Author Report Share Posted September 19, 2012 The reason I asked about gasket colour is because Sting referred to the different colours being different thickness. So... I figured if the colour determines the thickness then I could replace mine based on the colour of it. Right ok is the squish the measurement when: if I lay the cylinder on loosely then bolt it down it's the diff between the rested and bolted position??? I've got no idea there that's literally an educated guess! I am very mechanically minded I'm not alien to engines just never come across a situation where Ive ahd to measure squish. Quote Link to comment Share on other sites More sharing options...
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