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Post by Chuckwagon on Feb 21, 2016 15:16:34 GMT -5
Ok, thanks for the explanation on the cam seals. I'll have to dig into that and see what's what since it has been a while since I've seen them. I'm sure I'll have more questions when I get there. I do remember measuring distances to center the cam when I built the engine. I never checked the width of the seals, as I never knew there were different widths avaialbe/in use. I'm almost positive I got them from Mike's. Concerning the head torque, there is a lot of different information out there, that is for sure. I have this diagram taped into my Haynes manual from 5-6 years ago (without 5twins' watermark):  So do you advise I back off all the fasteners in sequence and incrementally, then torque back up to 30 ft/lbs, or just leave it where it is? What are the recommended torque values for the 8 mm bolts in the head? Some diagrams advise 14 ft/lb; I used 16. I am using brass washers for the 4 outer 10mm studs, for what it's worth. They have been trouble/leak free. As for my theory of the stainless acorn nuts being too shallow, I don't think that is an issue... they are the exact same dimensions as the other, original acorn nuts I'm using on the inner acorn nuts (at least looking at them from the outside. I obviously didn't pull them off to check thread depth on the inside... they are a Mike's product.) I am using a mix of stainless and chromed steel acorn nuts, so perhaps that is a problem. I also am using stainless allen head bolts in place of the stock steel bolts. The hardware was rusty, and when I first built the bike, I was on a stainless steel kick. Here was the starting point:  I use an allen wrench with a torque wrench adapter to get a torque measurment: www.motionpro.com/product/08-0380I forget what I'd paid for it when I worked at a shop and got a discount, but it has proved useful over the years. |
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Post by grizld1 on Feb 21, 2016 17:33:03 GMT -5
If I were you I'd leave the top end fasteners alone for now and focus on the valve cover leak. A leak there will throw oil all over the place, high and low (please don't ask how I know that). If torque is already at 35 ftlbs. I'd say stick with that, but don't go higher. 5twins and I have different ways of doing things when it comes to top end assembly. He leaves the fasteners dry and applies higher torque. I lube the fasteners and stop at 28 ftlbs. on the big nuts and 14 on the 8 mm. bolts We both think we get more accuracy with our respective methods.
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Post by Chuckwagon on Feb 21, 2016 21:15:57 GMT -5
Today I rechecked the torque after letting the engine cool and sit overnight... no change. I cleaned the engine of all the powder and oil oil so I could figure out where the engine is leaking. I removed the leaking rocker inspection cover and found the gasket was leaking, though everything looked ok in terms of metal surfaces. There was a little gasket residue, so cleaned that off, then glued the gasket to the eninge with gasgacinch, and left the cover side of the gasket dry so I can remove the cover without destroying the gasket. I rode the bike for 15 minutes and then set up a fan in the garage and let the bike idle on the work stand for a while while I watched for leaks. The valve cover leak seems fixed, and the base gasket is still dry, so that's progress. The head seems to be a little wet with oil, but not too bad. Not perfect, but I can probably live with it, and hoping maybe it is just old oil heating up and working itself out. So it seems with the valve cover addressed, that is a major and messy leak fixed.
The one leak that still seems active is in the timing cover (right side). Oil is seeping out of one of the philips head screws that holds the aluminum plate down - there are three of these, but only one that is leaking. Oil is just slowly pushing its way out. Weird thing was, I shut the bike off, and after 20 minutes, I came back and the oil was gone. It didn't drip down, just receded back below the screw. Given the amount of oil that came out during a short ride and some idling time, I can see that this would develop a decent amount of oil on a longer ride at higher speed/heat.
So is that oil that is working itself around the gasket under the aluminum plate, or is it oil coming from the cam seal? Seems like if the seal was leaking it would be coming down the center of the aluminum plate and/or hitting the advance and getting flung outward. What do you think?
As for the timing side (left side) I got pulled away and didn't remember to check that, but that side was just barely oily prior to cleaning the engine.
So, it is looking more promising... I think if I can fix the leak at the cam plate and/or seal, I'm willing to ride it more and see how it goes rather than tear the top end down... see if the head gasket leak is a mess, or if it is a minor annoyance.
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Post by grizld1 on Feb 21, 2016 22:52:47 GMT -5
Re. the cam cover leaks: it's a mistake to overthink this stuff. If I were doing it, I'd go around the screws with a hammer impact driver and see what happens.
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Post by Chuckwagon on Feb 22, 2016 9:10:58 GMT -5
I think I might try cleaning the threads with a shot of brake cleaner, then some thread sealer on the screws and tighten them.
Funny thing is that I used an impact driver (lightly) to seat those screws when I first did the engine 5 years ago. When I rebuilt it last winter, I found that the aluminum plate were slightly dimpled at the screw holes, so I resurfaced them to get them flat. Those plates are pretty thin. I guess it is a fine line between too loose and too tight.
For as much as I like these bikes, there are some wonky design flaws that carried through the model years.
It's ok though. When I feel frustrated with the xs, I just look over my shoulder at the triumph trident on my other lift. I'm getting that running for a friend... It has sat for 22 years. Got it going and it leaks oil from every possible hose and gasket.
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Post by mrriggs on Feb 22, 2016 13:25:25 GMT -5
The cam seals I got from Mike's leaked like crazy after a short time. I stuck some old seals off a parts motor in there and it fixed the leak. Looking at it more closely, the Mike's seals were 7mm wide double-lip, the old ones were 6mm single-lip. The second lip on the replacement seals rides too close to the ends of the cam.
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Post by grizld1 on Feb 22, 2016 16:42:56 GMT -5
I always use 7 mm. seals, but I order from 650 Central or a local indie shop, not Mike's XS. Mark, I've never had the kind of grief with the end covers that you're describing, and I hammer those screws down tight!
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Post by mrriggs on Feb 22, 2016 16:53:21 GMT -5
Are they single or double-lip? It's not so much the width as it was the extra lip that was an issue.
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Post by grizld1 on Feb 22, 2016 18:43:26 GMT -5
Installed a bunch of the darn things over the years, but it's been awhile--I want to say single lip, but I can't swear to it.
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Post by Chuckwagon on Feb 23, 2016 9:24:57 GMT -5
So are the recommended seals the OEM Yamaha seals or an aftermarket seal but not the aftermarket one that Mikes sells?
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Post by grizld1 on Feb 23, 2016 10:29:27 GMT -5
The OE seal is 25-40-6 (25mm. ID, 40 mm. OD, 6 mm. wide). The original manufacturer is the Japanese company ARS, which also sells to the aftermarket. Some kits will give you a 5 mm. seal; I've had no luck with those. You have two good recommendations to choose from; if you're in any doubt about what a particular vendor is offering, you won't go wrong spending a little more for the Yamaha logo.
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