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Post by waveydavey on May 1, 2022 22:08:51 GMT 1
![]() Hi all, I've just re-assembled my engine after stripping it and replacing all seals/bearings/gaskets, fitted to the frame, filled all the fluids and I have a fairly big problem.... I have a coolant leak from the underside of the crank case. It doesn't look good to me as I wouldn't have expected coolant to be in that location in the first place.. I'm wondering if anyone can help diagnose. It's coming from 2 studs on the lower crankcase, they are just to the rear of the crankshaft position. I tried to 'nip' the studs up a bit, but they were torqued to the correct value when I assembled the engine and it actually didn't make a difference. Gutted tbh as I spent literally all yesterday and today getting the bike prepped and now I'm wondering what I've done wrong. It seems like a gasket problem but not sure, so any help greatly appreciated. Will try to upload a photo. ![]() hosting.photobucket.com/images/i/waveydavey350/582DA479-A81A-45F7-9048-AA38B725AA14_1_201_a.jpeg ![]() Thanks, Dave. |
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Post by shaunthe2nd on May 1, 2022 22:16:39 GMT 1
I can't open your picture, but does sound strange.
Are you sure the leak isn't from the hose above the crank and the fluid running through the gap in the middle of the crankcase halves?
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Post by oldbritguy on May 1, 2022 22:17:56 GMT 1
Check your hose connections at the back of the cylinders I.e the one on the spigot on the cyl head and the one on the little ally pipe behind the clutch side. (Between the carbs)
There is a drain hole through the crank cases under the Reed blocks and if you have any coolant leak up top it will appear underneath at the studs you mentioned.
John
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Post by oldbritguy on May 1, 2022 22:18:41 GMT 1
Shaun beat me to it 😂
John
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Post by waveydavey on May 1, 2022 22:21:16 GMT 1
Hi - I need to get to grips with the photo uploading, will try again. I don't think it's coming from a hose above, but I will check to be absolutely certain. Thanks for the suggestion - will let you know tomorrow. this might work now??  |
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Post by midlifecrisisrd on May 1, 2022 22:30:53 GMT 1
As has been said it will be coming down through the drain hole in the crank case
It may still be the head but if you have used the cheap silicone hoses they can leak. Other suspect is the o ring on the coolant pipe going through the case to the pump
If it is coming from the head and you haven't started it yet undo the head bolts and barrel nuts
Finger tighten the barrel nuts then torque the head bolts
Then tighten the base nuts
Steve
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Post by 4l04ever on May 1, 2022 22:31:40 GMT 1
There is no coolant above those studs. It will be the hoses at the back of the cylinders. If they leak, the drain hole is just above those two studs...
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Post by waveydavey on May 1, 2022 22:31:58 GMT 1
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Post by waveydavey on May 1, 2022 22:38:14 GMT 1
Thanks guys, this give me hope!
I am using the original hoses, so that may be the problem. I got a new o-ring for the metal pipe going through the case but will also check that as there was some play in that pipe now that I think about it.
I will check these first thing tomorrow.
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Post by midlifecrisisrd on May 1, 2022 23:28:22 GMT 1
There can be pitting in the RH engine case where the water pipe sits too
Steve
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Post by JonW on May 2, 2022 1:48:36 GMT 1
If we had a £1 for everytime this coolant leak foxed someone as it leaks in a weird place via the special hidden hole lol we'd all be a bit better off  Its defo the pipe or the hose or the joins/clamps. Fiddly to fix but thats the location for sure, good luck! |
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Post by jon on May 2, 2022 9:01:40 GMT 1
I know you shouldn’t have to, but I’ve often wondered whether to use a smear of LSX on the spigots before assembly?
Jon
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Post by 4l04ever on May 2, 2022 10:00:01 GMT 1
Old hoses get bits of old aluminium corrosion in them where they are clamped on to the fittings, so may need a good clean too.
If you are not too fussy on originality, jubilee clips may make a better seal than the OEM wire clamps.
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Post by midlifecrisisrd on May 2, 2022 10:35:21 GMT 1
I know you shouldn’t have to, but I’ve often wondered whether to use a smear of LSX on the spigots before assembly? Jon Ah! Another fan of Fernox 😀 Great stuff Steve |
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Post by waveydavey on May 2, 2022 12:45:49 GMT 1
Problem found guys, thanks very much indeed for your help with this - everyone pointing to the right place! It seems I made a real hash of fitting the crankcase cover and didn't pay enough attention to the o-ring on the metal stub pipe... I will re-fit and re assemble. Thanks again guys, for a while I thought I was up for a complete engine strip down, you've really helped me out here  |
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Post by jon on May 2, 2022 13:06:25 GMT 1
Rookie error? I always smear a bit of red rubber grease on this seal on assembly for that reason.
Jon
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Post by waveydavey on May 2, 2022 13:23:47 GMT 1
Definitely a rocky error Jon, this is the first time I've completely stripped and rebuilt this engine. I had only ever done top end rebuilds on this bike (back many years ago).
Cheers,
Dave.
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Post by jon on May 2, 2022 13:28:48 GMT 1
I bought a half litre pot of red rubber grease years ago. I was told it would last me a lifetime. Not sure about that now, but it still has plenty of years left in it. Another favourite place to use it is on panel grommets. Makes them slide on easily which I always think helps stop them cracking?
Jon
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Post by waveydavey on May 2, 2022 13:37:14 GMT 1
Thanks for the tip. Will get some for the remaining jobs...seems like I should have bought some of this before now  |
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Post by arrow on May 2, 2022 14:24:15 GMT 1
Thanks for the tip. Will get some for the remaining jobs...seems like I should have bought some of this before now You can get a 150ml pot off ebay. Lasts years. |
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Post by Tobyjugs on May 2, 2022 17:40:50 GMT 1
Me I'm up to date and use either Molykote M55 or Molykote 111 depending on how the O-ring is fitted.
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Post by midlifecrisisrd on May 2, 2022 18:20:29 GMT 1
Me I'm up to date and use either Molykote M55 or Molykote 111 depending on how the O-ring is fitted. Is the 111 the silicone based stuff? Think I've got about 10 tubes of that 🤣 Steve |
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Post by Tobyjugs on May 2, 2022 18:29:27 GMT 1
Me I'm up to date and use either Molykote M55 or Molykote 111 depending on how the O-ring is fitted. Is the 111 the silicone based stuff? Think I've got about 10 tubes of that 🤣 Steve Yes both are the Molykote 111 is really sticky thick stuff great for O-rings in after market cylinder heads. I also use it for all things brake related and on titanium bolts to stop gauling (although I don't think that's an official use for titanium) |
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Post by midlifecrisisrd on May 2, 2022 18:39:16 GMT 1
Is the 111 the silicone based stuff? Think I've got about 10 tubes of that 🤣 Steve Yes both are the Molykote 111 is really sticky thick stuff great for O-rings in after market cylinder heads. I also use it for all things brake related and on titanium bolts to stop gauling (although I don't think that's an official use for titanium) We use it at work to lubricate EPDM peristaltic pump tubes and water proofing electrical connectors I ended up with 17 tubes at one point I ordered 2 tubes of 111 and 400 cable ties but they mixed up the order and sent me 2 cable ties. I kept getting the Moly delivered a few tubes at a time till I had 17 I only found out about the mistake when they phoned to say the Moly had come in to stock and did i still want the remaining 383 tubes from my order 😳 Steve |
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Post by Tobyjugs on May 2, 2022 19:04:06 GMT 1
Yes both are the Molykote 111 is really sticky thick stuff great for O-rings in after market cylinder heads. I also use it for all things brake related and on titanium bolts to stop gauling (although I don't think that's an official use for titanium) We use it at work to lubricate EPDM peristaltic pump tubes and water proofing electrical connectors I ended up with 17 tubes at one point I ordered 2 tubes of 111 and 400 cable ties but they mixed up the order and sent me 2 cable ties. I kept getting the Moly delivered a few tubes at a time till I had 17 I only found out about the mistake when they phoned to say the Moly had come in to stock and did i still want the remaining 383 tubes from my order 😳 Steve I don't think it's cheap to buy either. |
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Post by chrisg on May 2, 2022 20:31:15 GMT 1
When fitting the clutch cover, i always check the bore where the water tube/seal go. Ensure its clean and maybe polish with fine wet n dry.
Red rubber grease as well.
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Post by waveydavey on May 2, 2022 21:38:28 GMT 1
Update: I've fitted the new o-ring and refitted the crankcase cover, filled with coolant and....NO MORE LEAKS...yahoo! Thanks all! |
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