R1100RT - checking valve clearances

[SWB]

How much pressure is required to insert the feeler gauges into the valve gaps? I'm checking and adjusting my valves now.

 

On the right cylinder (from riding position), I wasn't initially able to get a blade into the intake valves, while the exhaust were pretty loose. I "rattled" both rocker arms, pushed just a bit on the intake side blade, and after overcoming the initial friction, both intakes felt pretty good (i.e. minimal drag), and I cross-checked them against a 0.17mm gauge - nope, too large. I adjusted the exhausts valves, which were pretty loose, and then moved on to the left cylinder.

 

Both intake and exhaust valves were pretty loose on the left cylinder. So, I worked on one side at a time, intake and then exhaust (because the feeler gauges wouldn't hold position, and I didn't have five hands to hold all four and do the adjustment too). After both intakes and exhaust were tightened, I again "rattled" rocker arms and retested. The intake feeler gauge blades were difficult to insert (as initially with the right cylinder), but I pushed a bit, they both slid in, and then I inserted the exhaust feeler gauges. Both intakes seem pretty balanced, and then both exhaust valves, i.e. there's just a minimal drag on all blades.

 

However, after I inserted two exhaust feeler blades, the intake blades loosened up. They are considerably looser and no longer quite balanced. So, they've gone from a point were I could almost not quite insert the blade, to fairly loose (perhaps 0.17mm versus 0.15mm). After I remove all four blades, and "rattle" the rocker arms, the cycle repeats, i.e. the intakes are initially tight, etc..

 

I know that this "dance" is the way it is, i.e. tightening one intake impacts the other, and tightening the exhausts impacts the intake valves. My question is, am I running the check properly, or am I "altering" the test by "forcing" (albeit gently) the feeler blades into position? Does the fact that the gap seems to open up mean that the valve spring is compressed, i.e. that the valve gaps are tighter than the feeler gauges make them appear?

 

This kind of stuff is probably obvious to more experienced hands; thanks for bearing with me on these questions.

 

- Scott

[DrPaul]

This has been my technique which works well for me. First, be sure the engine is COLD. I never used two feelers at a time but some say it is a good idea. I tighten the adjuster screw until the feeler won't slide with gentle force then tighten the lock nut. Tightening the lock nut usually opens the gap a tad and this usually allows the feeler to slip freely out of the gap. I use a nut driver and hand tighten this lock nut so as not to over tighten and strip. Then recheck. Seldom have to reset.

 

I'm puzzled by your last statement. Setting exhaust valves will have no impact on the intakes and visa versa unless you are turning the cam somehow.

[ShovelStrokeEd]

Scott,

Something is wrong there, I don't know if it your technique or something mechanical. Adjustment of the exhausts should not have any effect on the intakes.

 

The rockers for the intake and exhaust valves are supported/pivot on two separate shafts. There is an assembly that holds both shafts in place that is torqued down to the cylinder head.

 

Try this, loosen the lock nut and back the adjuster waaaay out. Now insert your feeler gauge between the wiggly thing on the end of the adjuster and the valve stem. Spin the adjuster in until it clamps the gauge, pull as straight as possible on the gauge while checking this and just spin the adjuster with the shaft of the allen wrench between your fingers. Basically, when it stops, you are in far enough. Now see what the pull feels like, the drag should be no more than what it takes to tear off a piece of toilet paper at the cut. Snug up your lock nut. I like the idea of using a nut driver here rather than a wrench. Check the feel again. Repeat until you get the idea. A final little tug with a short wrench and one last check and you should be done.

[John Dickens]

1. On the end of each rocker is a small pivoted pad which bears on the end of the valve stem. If this pad is tilted slightly you can't always get the feeler gauges in. It can give a false reading if you don't know it's there.

 

2. I use 'stepped' type feeler gauges, sometimes called 'go, no go'. Each blade has 2 thicknesses e.g. 0.011" and 0.013". If the thin section will go but the thick section won't then the gap is 0.012". Takes the 'feel' or guesswork out of using them.

[SWB]

1. On the end of each rocker is a small pivoted pad which bears on the end of the valve stem. If this pad is tilted slightly you can't always get the feeler gauges in. It can give a false reading if you don't know it's there.

 

2. I use 'stepped' type feeler gauges, sometimes called 'go, no go'. Each blade has 2 thicknesses e.g. 0.011" and 0.013". If the thin section will go but the thick section won't then the gap is 0.012". Takes the 'feel' or guesswork out of using them.

 

Using stepped gauges to cross check my work. Thanks!

[SWB]

Scott,

Something is wrong there, I don't know if it your technique or something mechanical. Adjustment of the exhausts should not have any effect on the intakes.

 

The rockers for the intake and exhaust valves are supported/pivot on two separate shafts. There is an assembly that holds both shafts in place that is torqued down to the cylinder head.

 

Try this, loosen the lock nut and back the adjuster waaaay out. Now insert your feeler gauge between the wiggly thing on the end of the adjuster and the valve stem. Spin the adjuster in until it clamps the gauge, pull as straight as possible on the gauge while checking this and just spin the adjuster with the shaft of the allen wrench between your fingers. Basically, when it stops, you are in far enough. Now see what the pull feels like, the drag should be no more than what it takes to tear off a piece of toilet paper at the cut. Snug up your lock nut. I like the idea of using a nut driver here rather than a wrench. Check the feel again. Repeat until you get the idea. A final little tug with a short wrench and one last check and you should be done.

 

I've read IBMWR documentation that indicates that, for whatever reason, after you've checked and adjusted the intakes, and then checked and adjusted the exhausts, occasionally the intakes will feel as though they've changed, even though they are on different shafts. So, I wasn't surprised when this happened, nor do I understand how it could happen mechanically, but it's reproducible.

 

I use four feeler gauges (plus a go-nogo gauge to cross check). The .15mm's go in fine, and then the .30mm's go into the exhaust side. When I put the fourth feeler gauge in the exhaust side, the two .15s suddenly go slack and the handles drop. When I recheck the intakes, what was a slight "drag" in resistance becomes pretty darn slick. The go-nogo gauge seems to indicate that the gap is still ok (e.g. .15-.17 will insert at the tip but not at .17mm).

 

My basic question is whether I'm screwing something up with the test reading by using any force to slip the feeler gauge in. I recognize the "small pivoted pad" that John describes, and that's probably the initial resistance I'm overcoming when I first insert the gauge, i.e. getting that pad into the right position. I'll try your recommendation about simply backing out the adjusters. Heck, "I'm already in there any way ...", as the saying goes. This is a learning experience. That's part of the reason I haven't ridden this "hanger queen" in 11 months.

 

Thanks all, learned a lot, confirmed some things, and now I'll go onto adjusting my rocker arms (as soon as I get a second .05mm gauge and a T45 Torx screw bit.

[smiller]

I've read IBMWR documentation that indicates that, for whatever reason, after you've checked and adjusted the intakes, and then checked and adjusted the exhausts, occasionally the intakes will feel as though they've changed, even though they are on different shafts.

Do you have the link? I'd like to see that, as I can't think of how one could possibly affect the other. I'd like to see exactly what was written. Are you certain that there's no issue with your technique, such as accidentally applying a bias on the gauge making it only seem that the gap has changed?

 

Also BTW, in your other thread about finding TDC... as Ed mentioned, piston movement around TDC will be quite small and it's hard to narrow down to the point that you can say with certainty that your 'OT' mark is a few degrees off without a dial indicator or some way to indicate when you are really at precise TDC. I've never really checked this on my bike but if the OT mark appeared to be a bit off from my casual 'chopstick' TDC setting I wouldn't think twice about it. If something was actually wrong in this regard on your bike I doubt it would run very well, if at all.

 

I think you are being way to anal about all of this Scott. Just adjust the valves, put it back together, and ride.

[T__]

Scott,

Something is wrong there, I don't know if it your technique or something mechanical. Adjustment of the exhausts should not have any effect on the intakes.

 

The rockers for the intake and exhaust valves are supported/pivot on two separate shafts. There is an assembly that holds both shafts in place that is torqued down to the cylinder head.

 

Try this, loosen the lock nut and back the adjuster waaaay out. Now insert your feeler gauge between the wiggly thing on the end of the adjuster and the valve stem. Spin the adjuster in until it clamps the gauge, pull as straight as possible on the gauge while checking this and just spin the adjuster with the shaft of the allen wrench between your fingers. Basically, when it stops, you are in far enough. Now see what the pull feels like, the drag should be no more than what it takes to tear off a piece of toilet paper at the cut. Snug up your lock nut. I like the idea of using a nut driver here rather than a wrench. Check the feel again. Repeat until you get the idea. A final little tug with a short wrench and one last check and you should be done.

 

I've read IBMWR documentation that indicates that, for whatever reason, after you've checked and adjusted the intakes, and then checked and adjusted the exhausts, occasionally the intakes will feel as though they've changed, even though they are on different shafts. So, I wasn't surprised when this happened, nor do I understand how it could happen mechanically, but it's reproducible.

 

I use four feeler gauges (plus a go-nogo gauge to cross check). The .15mm's go in fine, and then the .30mm's go into the exhaust side. When I put the fourth feeler gauge in the exhaust side, the two .15s suddenly go slack and the handles drop. When I recheck the intakes, what was a slight "drag" in resistance becomes pretty darn slick. The go-nogo gauge seems to indicate that the gap is still ok (e.g. .15-.17 will insert at the tip but not at .17mm).

 

My basic question is whether I'm screwing something up with the test reading by using any force to slip the feeler gauge in. I recognize the "small pivoted pad" that John describes, and that's probably the initial resistance I'm overcoming when I first insert the gauge, i.e. getting that pad into the right position. I'll try your recommendation about simply backing out the adjusters. Heck, "I'm already in there any way ...", as the saying goes. This is a learning experience. That's part of the reason I haven't ridden this "hanger queen" in 11 months.

 

Thanks all, learned a lot, confirmed some things, and now I'll go onto adjusting my rocker arms (as soon as I get a second .05mm gauge and a T45 Torx screw bit.

 

 

SWB, if your exhaust adjustment is effecting the intake valve clearance I would suspect worn cam bearings.. About the only other thing would be a loose valve gear carrier & that you could see..

 

I would presume the cam bearing radial clearance could be within spec & still move the intake clearance with exhaust loading but it should be very very slight..

 

Twisty

[Ken H.]

I hear you Ed (and others) but it's true. One of those great BMW mysteries that defy any logical explanation. But I've seen many a boxer where adjusting the exhaust ones effects an intake.

 

It's the main reason why I adjust valves with all 4 feeler gauges in at once.

[ShovelStrokeEd]

I really think this is nothing to worry about. To tell the truth, I never have bothered to check on any of my air or oil heads. I adjust using a different pattern than you guys. When the exhaust just cracks open, I adjust the intake valves, when the intakes just close, I adjust the exhaust valves. I even (gasp!) only use one feeler gauge at a time.

 

None of my bikes has ever failed to run to my satisfaction after this procedure, about 8 or 9 airheads and 4 oilheads.

 

This whole thing kinda makes me nuts. One or two thousandths of an inch will make zero detectable difference in the valve timing or in the pumping ability of the engine until you get into absolute peak power where, you may be able to detect a slight shift in the power peak relative to RPM. So long as you synch the throttle bodies after verifying that the valves are somewhere close to spec, you won't notice any difference in the feel of the bike either.

 

Get on with your lives, you bought these things to ride.

[SWB]

This whole thing kinda makes me nuts. One or two thousandths of an inch will make zero detectable difference in the valve timing or in the pumping ability of the engine until you get into absolute peak power where, you may be able to detect a slight shift in the power peak relative to RPM. So long as you synch the throttle bodies after verifying that the valves are somewhere close to spec, you won't notice any difference in the feel of the bike either.

 

Get on with your lives, you bought these things to ride.

 

Dang, and I thought perfection was possible in tuning!?

 

Finished the adjustment(s), fired her up, checked TB sync (was pegged dead-center on the Twinmax - no adjustment required), and took her out for her first ride in 120 days. It sounds ... wierd, as if I know what a BMW even sounds like any more. My son picked up two in-line-4 1K bikes (R1 and Gixer for a 20-year old; another entire story ), and after listening to those Japanese bikes, my twin sounds like it's gasping and wheasing. My RT sounds pretty good, responds well throughout all RPM ranges, is fast, maybe needs the idle advance tweaked a bit, but bascially - it runs pretty darn good.

 

I'm going to recheck TB balance in about 500 miles, since the throttle cables.

 

Thanks all.