How about remove the crankcase breather cover assembly. I realize that would necessitate buying/ making a new gasket but that way you could get a long wobble extension tight to the top frame tube and it wouldn't be on such an angle.
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head bolt retorque.
- Thread starter CDNTX650
- Start date
I'm gonna throw a word of caution out here that I'm sure everyone is aware of... but it bears repeating.
You're correct Pete, in that lube does give us a better or more accurate indication of torque. But that's only half the story. The reduction in friction also allows us to apply a lot more tension to a bolt (or stud in this case... same difference). In some cases, as much as 100% more tension. I fully realize that the service bulletin Gary put on page 1 calls for lubing the nuts and doesn't say to reduce torque... fair enough. I still don't think it's a good "common practice" to tighten a nut "lubricated" based on a "dry" torque value.
I'm including a pdf below (only two pages long) that was written by NASA. It pretty starkly shows the difference and I tend to trust the folks that put us on the Moon
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yamageddon
XS650 Addict
I thinks it's the same discussion that you often encounter on wheel nuts:
Indeed, and Jim is correct in that if you overdo the lubrication, you can over-torque a fastener.
I advocate cleaning the threads and nut face of any gunk or rust and then applying a tiny dab of anti-seize paste under the nut to prevent seizing so that I can get it apart later.
The key thing is to make sure that things are clean and that all of the fasteners are able to supply equal axial (squeezing) force for a given torque value. If some of the fasteners are clean and others are dirty/seized, then you will have no way of knowing what the force distribution is across the gasket surface....and you will likely wind up with a leak.
Pete
I advocate cleaning the threads and nut face of any gunk or rust and then applying a tiny dab of anti-seize paste under the nut to prevent seizing so that I can get it apart later.
The key thing is to make sure that things are clean and that all of the fasteners are able to supply equal axial (squeezing) force for a given torque value. If some of the fasteners are clean and others are dirty/seized, then you will have no way of knowing what the force distribution is across the gasket surface....and you will likely wind up with a leak.
Pete
No offense, guys, but I tend to trust Yamaha and 26 years of experience with XS650 motors. A word to the wise: if you see oil around the cylinder base, be aware that well over 75% of the time it's coming from the cam chain adjuster, not from the cylinder base. Go around those six 6 mm. screws gently before you panic.
Good point Grizld1 - and a very important tip for us all!
Pete
Pete
Pete, Jim, another one that could use ya'll's critique.
http://www.xs650.com/threads/what-to-use-on-the-bolts-for-a-top-end-job.27533/
Another torque chart.
Covers dry/lubed with bolt grade.
Needs to be converted to ft-lbs.
That chart's for steel into steel. I found another one, somewhere, that shows reduced values for steel bolts into aluminum. It shows max torque for lubed 6mm bolts into aluminum to be 4 ft-lbs. Think sump and sidecovers. Need to find that chart again.
http://www.xs650.com/threads/what-to-use-on-the-bolts-for-a-top-end-job.27533/
Another torque chart.
Covers dry/lubed with bolt grade.
Needs to be converted to ft-lbs.
That chart's for steel into steel. I found another one, somewhere, that shows reduced values for steel bolts into aluminum. It shows max torque for lubed 6mm bolts into aluminum to be 4 ft-lbs. Think sump and sidecovers. Need to find that chart again.
I’ll check around 2M.
Pete
Pete
38 Nm=28 ft-lbs. 19 Nm=14 ft-lbs. Do those numbers look familiar at all, gents?
and that darned near impossible to get at tiny little bolt above the chain tensioner! Start by loosening, good chance it is loose anyways. Then GENTLY snug it up. At ANY sign it's starting to pull tiny aluminum threads out of the head, STOP! Quick recap; it should turn freely then you should feel the bolt head make contact with the cam cover, now it will take up just the slightest bit of clearance between cam cover, gasket, and head. Stop now and revel in the wisdom in your fine mechanical feel.
Hint; practice "getting the feel" in some non critical bolt like an allen head on the LH clutch adjuster cover. Note the advantage to feeling that just right torque. Remove bolt, spritz some cleaner in the hole, blow it out with an air gun, clean the bolt threads, then reassemble with a smidgen of motor oil or anti-seize. DO NOT GLOP on anti-seize, just enough to see some has transferred from the brush to the bolt threads. If, after cleaning, the bolt still does not thread easily so feeling the head touch is simple, carefully align and run a bottoming tap in and out of the hole a time or two, repeat spritz and blow clean out. Also inspect the bolt threads, at any sign of damaged thread REPLACE! Good bolt threads are critical, the
$$$ aluminum will always loose.
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Yup - that does compute Grizdl1.
- 38 Nm = 28 ft-lb
- 19 Nm = 14 ft-lb
If you cannot tell the difference between aluminium and steel - use a magnet (most alloys of steel are magnetic while aluminium is not magnetic). Also, if you can't tell the difference, perhaps this job is not for you.....
RELATED - BUT SLIGHTLY DIFFERENT POINT ABOUT FASTENER TORQUE
I installed a new bathroom vanity and two new sinks this past weekend and was explaining to my wife that a good practice is to tighten a fluidic connection until you think it won't leak and then try it. If it does leak - snug it up just a teensy bit more - and see if it stops leaking. Repeat as necessary until it stops leaking (and it nearly always does after one or two cycles of this procedure).
If you start out with the thing reefed right-up tight, you will likely damage or distort the fitting - and then you have nowhere to go but replacement.
Now - the reason I raise this story is that it is in accord with Gary's method of securing that hard-to-reach little 6mm bolt above the cam-chain tensioner on our XS650s. Basically, you cannot get a torque wrench on this danged bolt with the engine in the bike - and so I suggest that you loosen it off, clean it (especially underneath the bolt head) and then snug it up...juuuuust...enough (this does take some amount of finesse). Then, run the engine and see if it leaks and if it does, try one or two more tiny little snugs, and it will likely stop.
If it doesn't stop, well engine oil is pretty cheap, as are paper towels and it is better than having to dismantle the entire engine to install a Helicoil thread insert.
Pete
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The method Gary recommends is probably more accurate than most torque wrenches (unless employed by someone with numb fingers or too many beers on board). Even with most good inch-pound wrenches you'll be working at the low end of the range, and if you can get accuracy there better than +/- 20%, you have an exceptional instrument.
In my Air Force days we used to say that for consistency... "run 'em all down 'till they strip... then back 'em off a half a turn."
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I like to think Yamaha took into account that the threads were supposed to be lubricated when they speced the head bolt torque values. I have a neat little free metric conversion program that really comes in handy for stuff like this. Some of the older manuals don't give ft/lb conversions for their torque values, and if they do, sometimes they're wrong. With this little program, I can check for that. It's also nice that you can open multiple examples of the program at the same time and each one can be used/inputted individually, as shown below .....
I use anti-seize on practically every fastener on the bike. I use the copper-based stuff (C5-A or equivalent) as opposed the to silver colored nickel-based stuff. The copper colored stuff shows up better on the threads so it's easier to determine when enough has been applied, or when it's time to re-apply on an often removed fastener (axle nuts, side cover screws, etc.). Basically, I "paint" it on with a small brush. I give the fastener an even, smooth coating with no lumps or globs, just like a coat of paint. On a long shouldered bolt where the shoulder fits inside the part too, I coat that shoulder as well. This is for corrosion resistance and the engine mounting bolts come to mind as a perfect example.
I've been slowly backing off the amount of torque I use on M6 fasteners over the years. The usual spec is something like 5 to 8 ft/lbs. When I got my 1st in/lb torque wrench years back, I thought I was golden and proceeded to use the max, 8 ft/lbs or 96 in/lbs - until I eventually stripped one, lol. That's when I started backing off. I decided on 80 in/lbs (about 6 2/3 ft/lbs), not sure why, and it has worked well for me. But on these old bikes and alloy cases, I'm starting to back that off a little now, into the low 70's (about 6 ft/lbs).
I use anti-seize on practically every fastener on the bike. I use the copper-based stuff (C5-A or equivalent) as opposed the to silver colored nickel-based stuff. The copper colored stuff shows up better on the threads so it's easier to determine when enough has been applied, or when it's time to re-apply on an often removed fastener (axle nuts, side cover screws, etc.). Basically, I "paint" it on with a small brush. I give the fastener an even, smooth coating with no lumps or globs, just like a coat of paint. On a long shouldered bolt where the shoulder fits inside the part too, I coat that shoulder as well. This is for corrosion resistance and the engine mounting bolts come to mind as a perfect example.
I've been slowly backing off the amount of torque I use on M6 fasteners over the years. The usual spec is something like 5 to 8 ft/lbs. When I got my 1st in/lb torque wrench years back, I thought I was golden and proceeded to use the max, 8 ft/lbs or 96 in/lbs - until I eventually stripped one, lol. That's when I started backing off. I decided on 80 in/lbs (about 6 2/3 ft/lbs), not sure why, and it has worked well for me. But on these old bikes and alloy cases, I'm starting to back that off a little now, into the low 70's (about 6 ft/lbs).
Based on the table in Entry 67 lubricating the threads would require reducing the torque setting by approximately 25% to match the dry torque setting.
I used 27ftlb lubricated which is equivalent to approximately 36ftlb dry. Should I be reducing the torque settings to 20ftlb lubricated to be equivalent to the specification 27ftlb dry? I could systematically back off each nut a half turn and slowly reduce the torque - this would probably take 2 or 3 cycles to complete.
I am due to recheck the torque settings now after putting 1000 miles on a rebore.
Thank you for any suggestions
I used 27ftlb lubricated which is equivalent to approximately 36ftlb dry. Should I be reducing the torque settings to 20ftlb lubricated to be equivalent to the specification 27ftlb dry? I could systematically back off each nut a half turn and slowly reduce the torque - this would probably take 2 or 3 cycles to complete.
I am due to recheck the torque settings now after putting 1000 miles on a rebore.
Thank you for any suggestions
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I use a similar one called Convert. I used to require my students download and become familiar with it.
It really is a useful little program. 'Course, nowadays I just say "hey google, convert blah blah blah....."
Yeah... what that NASA paper alluded to but didn't go into detail on is re-used fasteners. The more a fastener is used, the more "polished" the threads become. This polishing reduces friction, thus increasing the amount of tension applied for a given torque. Add to that each "tension cycle" gets us that much closer to metal fatigue... and it's completely understandable why older hardware tends to strip easier...
Well Steve... after reading that thread, it's becoming clearer to me why we're all over the place on this (I suggest you guys give it a read). You put up a shot of your "old Yamaha manual" that clearly stated you are to lube the head fasteners. My 78-80 manual says no such thing.
Your old manual....
My 78-80 manual....
Perhaps because the Unified Bearing Stress (UBS) system nuts are used on the newer engines?
I also just checked this one (77?) and it makes no mention of lubing the fasteners...
Any of this helping you reach a decision Paul?
Yeah - pretty confusing. My guess is that somebody at Yamaha Engineering had a bee in their bonnet about lubing threads and went to war over it - leading to a re-write of the various manuals.
Not having studied the matter in great depth, I think that I'd go with the latest information and just make sure that the threads and under-head areas of the fasteners are clean and have a dab of anti-seize on them.
Pete
Not having studied the matter in great depth, I think that I'd go with the latest information and just make sure that the threads and under-head areas of the fasteners are clean and have a dab of anti-seize on them.
Pete
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