Jump to content

Valve gaps - how much 'drag'? And crossover question, too&#33


Repeater

Recommended Posts

Good afternoon. After about 700 miles on the LeMans I bought a few weeks ago, it was running up close to 6000 miles, so it was time for some service. Picked up a bunch of oil, a new filter, prepared to install my Roper Plate mod, and do the valve lash adjustments.

 

To my surprise, the Roper plate installation seemed to go quite smoothly. Fiddly, but I took my time, and it seems to have paid off. I have the side stand back on, but I didn't cut the relief in the bracket, so I'll probably do that sometime in the not-too-distant future.

 

I also managed to cross-thread one of the valve cover bolts on the right cylinder after the valve adjustment, but that's neither here nor there - stupid mistake on my part, as I think I was rushing it to do the other side.

 

Anyhow, all of the valves seemed very, very loose. About twice what the recommended gaps are! This made me think - I know you're supposed to use a 'slight drag' on the feeler gauges to get the correct gap. But it makes me think that that slight drag might be close to no drag at all or "damned close to forcing it in there", depending on whom you talk to. What metrics do most folks use? Any rules of thumb to be aware of? I tried going with the .006/.008 spec this time around, so we'll see how it goes, I guess.

 

My second question this time - my LeMans has the crossover pipe right in front of the engine... but it's loose. Not just a little loose, either, it's really, really loose. Is it safe to assume that it's not supposed to be loose, and it's missing a gasket of some sort? Both clamps on both pipes are as tight as they'll go, but the crossover pipe remains very loose...

Link to comment
Share on other sites

Hey Repeater, For the feeler gauges: "slight drag" means just that. No effort at all should be required to slide the gauge in or out of the gap, nor should the next .001" up slide in without some feeling that it is "dragging" or requires you to push it to get it started. The important thing here is that you do the work, so you should develop your own feel, and then you will set your valves consistently, where you are happy with the way it runs.

The floppy front crossover topic is a commonly discussed thread, and can be easily researched using the "Search" function just under the "V11" homepage banner. I just checked in on my thread, "Does this merit a bodge point?" in the "How to" forum to confirm that mine is still tight with my cheap ass method in the picture. Hope that helps, good luck. Great inner reward goes to he that services his own ( and at least you know who to blame when it's all fargged up...) :luigi: Carry on, S.H.

Link to comment
Share on other sites

Guest ratchethack
Anyhow, all of the valves seemed very, very loose. About twice what the recommended gaps are! This made me think - I know you're supposed to use a 'slight drag' on the feeler gauges to get the correct gap. But it makes me think that that slight drag might be close to no drag at all or "damned close to forcing it in there", depending on whom you talk to. What metrics do most folks use?

There seem to be 5 "Rules-o-Thumb". Plenty of choices for those who're "all thumbs". ;)

 

If you're looking for consensus, I reckon World Spec might be as close as there is.

 

Beyond that, we have people on this Forum using:

 

1. .002 and .004, OE from Mandello, "US Spec".

2. .004 and .006, OE from Mandello, "World Spec".

3. .005 and .007, Pete Roper's "Bungendore Spec".

4. .006 and .008, "Seat-o-the Pants Spec". (My choice for hot weather and year round where I live)

5. .008 and .010, "Raceco Spec".

 

So depending on wot you mean by "very, very loose", if you went DOWN to .006 and .008, it may or may not have been "out-o-whack". . . :huh2:

 

The correct technique is as you describe -- you should "just feel"a little drag, as opposed to feeling no drag. If you want to try to dial this in any finer than that description generally means, you'll need a microscope, you'll go cross-eyed and probably impotent, and your Guzzi won't appreciate it one bit. :lol:

 

My second question this time - my LeMans has the crossover pipe right in front of the engine... but it's loose. Not just a little loose, either, it's really, really loose. Is it safe to assume that it's not supposed to be loose, and it's missing a gasket of some sort? Both clamps on both pipes are as tight as they'll go, but the crossover pipe remains very loose...

See recent "How To" thread, and many many others.

 

If I had a V11 with a front crossover, I'd skip the endless headaches altogether before they became a steady ball and chain on the enjoyment of my Guzzi, and replace the headers with crossoverless headers, either OE from Guzzi, or Todd Eagan's "guaranteed no crack" stainless replacement headers. But o' course, that's just me.

 

See GuzziTech.com:

 

http://www.guzzitech.com/store/GT-R-Hdrs.html

 

Have fun. :luigi:

Link to comment
Share on other sites

Excellent - thanks, guys! It's appreciated.

 

I'm pretty confident in my valve-measuring ability, so what I adjusted it to is definitely greater than what the US Spec is. In that, I think I have no worries.

 

Good advice on the Crossover - I'll get to work on it when time allows. Thanks again.

Link to comment
Share on other sites

I use the "if it'll hang there without slipping out under its own weight" rule of thumb, which with my gauge set is quite a bit more than a slight drag. I use 0.006 and 0.008 settings on everything from Eldorados to V11 Sports. The guys in the MI shop use 0.005 and 0.007.

Link to comment
Share on other sites

Well, just found out that neither of my valve cover gaskets seemed to have survived in a functional capacity, as I have a bit of oil seepage up there. Looks like the Suzuki will get full-time duty until I can get new gaskets anyway!

 

On a good note, I don't see anything amiss with the roper plate install...

Link to comment
Share on other sites

Guest ratchethack
Well, just found out that neither of my valve cover gaskets seemed to have survived in a functional capacity, as I have a bit of oil seepage up there. Looks like the Suzuki will get full-time duty until I can get new gaskets anyway!

 

On a good note, I don't see anything amiss with the roper plate install...

FWIW, though I've kept a new set of rocker cover gaskets in "spares stock" for 6 years, I haven't used them yet at 35K miles. If you clean the originals (and mating surfaces) free of oil with lacquer thinner or other solvent, then very sparingly work just enough GE II Silicone Seal (or equivalent) into them with your fingers, just enough to make the surface shiny (a few U$D for a 10+ oz. cartridge for the caulking gun size), and are quick enough about it to install them before the silicone "skins over", it will neither weep, nor seep between valve adjustments, and gaskets can be re-used for at least as many times as I've re-used mine (lost count years ago, but it's in my maint. record).

 

Congrat's on the Roper plate install. Success in this case is measured by a 'boring' lack of oil press. idiot light glimmer and associated lack of torched crank symptoms (traditionally hearalded by the infamously dreaded "dogga-dogga" sound). :o

Link to comment
Share on other sites

.... Looks like the Suzuki will get full-time duty until I can get new gaskets anyway!

 

 

Good God man, get those gaskets!

Link to comment
Share on other sites

If you are unsure of checking by 'feel' use a one thou larger and one thou smaller guage as 'Go'/'No-Go' guages. Basically though it isn't super-critical. s long as it will go in and doesn't flap about like a cock in a sock you're close enough.

 

Pete

Link to comment
Share on other sites

1. .002 and .004, OE from Mandello, "US Spec".

2. .004 and .006, OE from Mandello, "World Spec".

3. .005 and .007, Pete Roper's "Bungendore Spec".

4. .006 and .008, "Seat-o-the Pants Spec". (My choice for hot weather and year round where I live)

5. .008 and .010, "Raceco Spec".

 

Just to be clear. When Specs are given for valve clearances as RH has given above; I assume the industry standard is the first number represents the INTAKE valve and the second number the EXHAUST.

 

Raceboy

Link to comment
Share on other sites

Another technique for teaching yourself the "feel" of feeler gages is to..GENTLY..use a micrometer to measure the feeler gages in question.

With the mic gently stopped down on the gage, say your favorite .004", it should not pull out if you are using the correct force.

Now back off by .0025" or until the gage just slips out and you'll be experiencing what the home tuner should expect as damn close accuracy.

Link to comment
Share on other sites

Just looked at my receipt from them, a pair of valve cover gaskets for all "square head" Moto Guzzis is P/N MG3760 S/2, priced at $21.95 + shipping. Look in the menu running down the left side of the page, takes you right there. I also ordered the oil pan gasket, but it is too small, was able to return it no problem.

Also, I use the same method as ol' Pete for the feeler gauges, I have a collection of .004-.010 and more. On the intake, a .005 is sloppy loose, the .006 slips in , and the .007 takes a "push", and drags out with some "interference".

Link to comment
Share on other sites

Another technique for teaching yourself the "feel" of feeler gages is to..GENTLY..use a micrometer to measure the feeler gages in question.

With the mic gently stopped down on the gage, say your favorite .004", it should not pull out if you are using the correct force.

Now back off by .0025" or until the gage just slips out and you'll be experiencing what the home tuner should expect as damn close accuracy.

 

 

Are you a machinist?

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...