For sure!
At the rate I'm going, I'll be lucky to have 200 miles on the bike before I leave for the Iron Horse.....
Pete
At the rate I'm going, I'll be lucky to have 200 miles on the bike before I leave for the Iron Horse.....
Pete
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Lucille pulls another one on me....
- Thread starter MaxPete
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We always find the means to do what we loveto do! Good luck!
MaxPete, are you able to make any comments regarding the noise of elephant feet vs that of stock lash screws???
Thanks.
Thanks.
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Well, get off your ass and get out and ride! Lol!
Hi All: sorry for the silence: my “life” got in the way of my fun <again> 
On my way to Toronto for yet another business meeting (by car) I did manage to return Robin’s sturdy engine removal bars and straps to his home in London and he had kindly made me a couple of truck mud-flap licence plate reinforcement plates to head-off the dreaded XS650 licence plate destruction program which seems afflict these bikes, for some reason.
Perhaps there is something to what people say about these old Yamahas vibrating a bit....
PAUL: I would say that the elephants feel valve adjuster screws run significantly quieter than the stock arrangement of a valve adjuster screw with a hardened and radiused end. That certainly seems logical to me as the load is spread out over a much larger area. Thus, the tendency of the adjuster screw to hammer a dent into the top of the valve stem is essentially eliminated versus the stock arrangement which boils down to a point load between a flat surface (the tip of the valve stem) and the radiused end of the adjuster screw. In a point load situation, the oil film is bound to be less effective at cushioning the blow and thus, the stock adjuster is going to be noisier. The diameter of the “foot” of the E-F adjuster is actually larger than that of the valve stem, so you have two flat surfaces pressing on each other with a significant film of oil between them. As I mentioned the other day - a guy in a gas station actually walked over and asked me how I had gotten the bike to run so quietly (he had owned one years ago).
Checking the valve adjustment gap with a feeler gauge is the same as with a conventional adjuster.
The only downside of the elephants foot adjuster is that one must grind a small (maybe 3/16” or around 3.5mm deep) conical depression in the underside of the end of the rocker arm to allow the top of the “foot” a bit of clearance. If this isn’t done, you won’t be able to assemble the top of the cam cover onto the cylinder head and there will be no valve clearance at all. The amount of material removed (and thus, the loss of thread engagement in the adjuster hole) is minor and in any event, the assembly is loaded in compression so there is no risk of the adjuster threads pulling or stripping out of the rocker arm. Overall, I’m very happy with them and will certainly use them again in my second XS650 engine.
MARLIN: You betcha - trying my best!
I’m now up to about 170 miles since the rebuild. Today, I will change the oil and clean both filters and do a re-torque of the cylinder head. The first re-torque at 130 miles saw each acorn nut take between 1/4 and about 3/8 of a turn to reach the specified 35 ft-lb - so we’ll see how this one goes.
Cheers,
Pete
On my way to Toronto for yet another business meeting (by car) I did manage to return Robin’s sturdy engine removal bars and straps to his home in London and he had kindly made me a couple of truck mud-flap licence plate reinforcement plates to head-off the dreaded XS650 licence plate destruction program which seems afflict these bikes, for some reason.
Perhaps there is something to what people say about these old Yamahas vibrating a bit....
PAUL: I would say that the elephants feel valve adjuster screws run significantly quieter than the stock arrangement of a valve adjuster screw with a hardened and radiused end. That certainly seems logical to me as the load is spread out over a much larger area. Thus, the tendency of the adjuster screw to hammer a dent into the top of the valve stem is essentially eliminated versus the stock arrangement which boils down to a point load between a flat surface (the tip of the valve stem) and the radiused end of the adjuster screw. In a point load situation, the oil film is bound to be less effective at cushioning the blow and thus, the stock adjuster is going to be noisier. The diameter of the “foot” of the E-F adjuster is actually larger than that of the valve stem, so you have two flat surfaces pressing on each other with a significant film of oil between them. As I mentioned the other day - a guy in a gas station actually walked over and asked me how I had gotten the bike to run so quietly (he had owned one years ago).
Checking the valve adjustment gap with a feeler gauge is the same as with a conventional adjuster.
The only downside of the elephants foot adjuster is that one must grind a small (maybe 3/16” or around 3.5mm deep) conical depression in the underside of the end of the rocker arm to allow the top of the “foot” a bit of clearance. If this isn’t done, you won’t be able to assemble the top of the cam cover onto the cylinder head and there will be no valve clearance at all. The amount of material removed (and thus, the loss of thread engagement in the adjuster hole) is minor and in any event, the assembly is loaded in compression so there is no risk of the adjuster threads pulling or stripping out of the rocker arm. Overall, I’m very happy with them and will certainly use them again in my second XS650 engine.
MARLIN: You betcha - trying my best!
I’m now up to about 170 miles since the rebuild. Today, I will change the oil and clean both filters and do a re-torque of the cylinder head. The first re-torque at 130 miles saw each acorn nut take between 1/4 and about 3/8 of a turn to reach the specified 35 ft-lb - so we’ll see how this one goes.
Cheers,
Pete
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And cheers to you, too. I also bought the elephants feet thinking that as soon as they come in, I'll install them. Rat farts! Can't do. And i guess I'll hav to put up with the tink, tink, tink for a while. Hopefully 10 years or more.
Yup - unfortunately, installing the elephant's foot adjusters requires the engine-out and cylinder head-off.
Having said that, those tasks are not really a big deal, nor is the modification to the rocker arms.
Cheers,
Pete
Having said that, those tasks are not really a big deal, nor is the modification to the rocker arms.
Cheers,
Pete
Hey Max, when you're re-torquing the head bolts, are you breaking them loose and then going back up to torque specs or do you simply torque to specs as they sit? I've always loosened and then re-tighten/torqued them...but perhaps that's been a mistake? Just curious what others do...
On a fresh re-build like Pete is dealing with, there's no need to crack the bolts loose first. On one that's never been apart, it's a good idea to do so. The nuts and/or bolts could be stuck on the threads and give a false torque reading (tight enough when they're really not). On an undisturbed head, I usually remove each nut/bolt first, one at a time, clean and lube (anti-seize) the threads, then torque.
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I believe that 5twins recommended putting anti-sieze on the threads. I did and no loosening required. Without it, there is too much static friction to overcome.
Good to know, and that makes sense. Thanks guys!!!
Yes - 5Twins and Marlin are correct - and so is Brassneck. You should always break loose and lubricate fasteners that have been in-place for a long time.
In my case - the bike was apart 10 days ago and everything was totally cleaned up and then reassembled with lubrication on the threads - so there is no need to break them loose or apply more lube at this stage of the game.
Remember that when you torque a fastener (nut / bolt - whatever....) you don't really want torque on the bolt. What you are actually trying to do is generate a clamping force between the two things that the fastener is holding together (in this case the XS650 engine cam cover, cylinder head and barrel). The nut advancing down the threads of the stud is merely a good way to create that axial clamping force.
Unfortunately, we cannot measure the axial clamping force in the bolt or stud directly - so we use the applied torque as a surrogate measurement. For the applied torque to translate fully, predictably and accurately into an axial clamping force, you need to reduce the friction in the threads and under the head of the bolt or nut to the lowest possible level.
If you're having trouble with that concept - imagine the following:
>>> all of the applied torque on the nut is going into trying break the weld so that the nut can turn on the threads.
Until that nut turns relative to the stud - NO clamping force is generated. This is the same situation you would have trying to torque a fastener that is sticking or even seized on the stud. You can make your torque wrench click - but you are not generating any axial clamping force that will compress the gaskets to keep the oil in.
The other key point is that for a cylinder head-barrel joint you want all of the studs and bolts to apply the same axial clamping force evenly across the entire surface so that the gaskets are uniformly compressed and the engine is sealed and doesn't leak. Soooo...you want the applied torque to create the same clamping force in each stud - rather than having one stud that is loose, while the others are tight.
I have attached a .pdf of a slide from a presentation I gave to our local vintage bike group (www.CVMG.org) that shows the effect on the axial clamping force from a given level of applied torque and also the consistency of force for a given applied torque for lubricated versus non-lubricated fastener threads.
For unlubricated fasteners, the axial force (in the slide it is called "preload") varies from a low of 23 kN to more than 40 kN for the same applied torque - a huge variation. For the lubricated fasteners, the variation is much less - and so if that was data for the studs on a cylinder head, the force holding the head on would be much more consistent and the gasket would be less likely to leak. Interesting - eh?
Pete
In my case - the bike was apart 10 days ago and everything was totally cleaned up and then reassembled with lubrication on the threads - so there is no need to break them loose or apply more lube at this stage of the game.
Remember that when you torque a fastener (nut / bolt - whatever....) you don't really want torque on the bolt. What you are actually trying to do is generate a clamping force between the two things that the fastener is holding together (in this case the XS650 engine cam cover, cylinder head and barrel). The nut advancing down the threads of the stud is merely a good way to create that axial clamping force.
Unfortunately, we cannot measure the axial clamping force in the bolt or stud directly - so we use the applied torque as a surrogate measurement. For the applied torque to translate fully, predictably and accurately into an axial clamping force, you need to reduce the friction in the threads and under the head of the bolt or nut to the lowest possible level.
If you're having trouble with that concept - imagine the following:
- the acorn nut on the end of a cylinder stud is not tightened and is just sitting loose (so the cylinder head is NOT held down onto the top of the barrel);
- you weld the acorn nut and the stud together so that they are rigidly connected to each other;
- NOW - you use your torque wrench on the acorn nut;
NONE - bupkiss / nada / SFA!!!
Until that nut turns relative to the stud - NO clamping force is generated. This is the same situation you would have trying to torque a fastener that is sticking or even seized on the stud. You can make your torque wrench click - but you are not generating any axial clamping force that will compress the gaskets to keep the oil in.
The other key point is that for a cylinder head-barrel joint you want all of the studs and bolts to apply the same axial clamping force evenly across the entire surface so that the gaskets are uniformly compressed and the engine is sealed and doesn't leak. Soooo...you want the applied torque to create the same clamping force in each stud - rather than having one stud that is loose, while the others are tight.
I have attached a .pdf of a slide from a presentation I gave to our local vintage bike group (www.CVMG.org) that shows the effect on the axial clamping force from a given level of applied torque and also the consistency of force for a given applied torque for lubricated versus non-lubricated fastener threads.
For unlubricated fasteners, the axial force (in the slide it is called "preload") varies from a low of 23 kN to more than 40 kN for the same applied torque - a huge variation. For the lubricated fasteners, the variation is much less - and so if that was data for the studs on a cylinder head, the force holding the head on would be much more consistent and the gasket would be less likely to leak. Interesting - eh?
Pete
Fascinating. So lets say you're torquing a bolt to 14 ft. lbs.... if it's lubed with anti-seize, would the torque value need to change? I thought I read that somewhere...
No - the quoted torque values in engine and machinery specifications and manuals are predicated on lubricated threads that are clean (no corrosion, dirt or other debris).
That is why so much old stuff leaks I think: people use the specified torque but DON"T clean and lubricate the threads and so the gasket clamping forces wind up being much too low because much of the applied torque goes into trying to overcome friction on the threads and under the heads of the nuts and bolts.
Pete
That is why so much old stuff leaks I think: people use the specified torque but DON"T clean and lubricate the threads and so the gasket clamping forces wind up being much too low because much of the applied torque goes into trying to overcome friction on the threads and under the heads of the nuts and bolts.
Pete
Makes sense to me.
Yeah. I have problems with friction on my nuts too, sometimes.
Don’t we all.
The head stud torque specification for the XS specifies what the threads should receive "... a liberal coating of 30 weight oil ...". I realize that many have had success using other lubricants or anti-seize, but the specification calls for 30 weight oil. So what is the difference?? I have in the past looked up data comparing the use of alternatives to motor oil. Both anti-seize and Molybdenum Disulfide grease result in over-tightening, about 20% higher for anti-seize and 50% for Molybdenum Disulfide grease. If you want to follow the Yamaha specification closely you should use 30 weight oil and nothing else.
Hmmmmm....good to know. Thanks Paul.
I tend to go toward the middle of the torque spec on things. My manual says 25-35 ft-lb for the acorn nuts - so I set my wrench at about 30 ft-lb.
Pete
I tend to go toward the middle of the torque spec on things. My manual says 25-35 ft-lb for the acorn nuts - so I set my wrench at about 30 ft-lb.
Pete
MaxPete, after having used Molybdenum Disulfide anti-seize on mine I backed them off to 25ftlb. Next time I will clean the threads and use 20W50 even though that is a bit naught for a purest.