Adjustments after rebuild

XSiveAl · Posted: May 28, 2009, 11:30 am Post subject: Adjustments after rebuild

Hey All,

I've got a good question for you guys who've rebuilt and broke-in.
I have done the following.. with your help.

-new cam chain, valves (stainless exhaust!) & guides (profesionally installed), new piston pins & rings, & contact points, and advance springs too, honed and put it all back together. adjusted timing and clearance correctly.. retorqued three times. even bought brand new feeler gauges to make sure they're perfect.

made damn sure I followed all the instructions between this site and my original yamaha factory manual

I had some carb overflow issues (sinking float) so I've changed the oil 3 times this week..new floats and float valves fixed that!

bike runs awesome!! so much power it's scary.. sit and run all day nice and even if i let it. I've run it in short trips for about 185km now.. super happy!!

but,.. after it reaches operating temperatue the clearance of the intake valve changes enough to make it pretty noisey.. I know they're a noisey old engine but,.. it seems to me if it's quiet when it's cold it should be just as quiet when it's hot. the exhaust valves don't change.. they're right on and sound beautiful.

I understand that usually you have to adjust things a few times to get them to seat.. retorque changes chain length, changes timing, changes valve clearance etc.. but how many times is normal? do i just keep running it, allow to cool overnight, re-adjust,.. do it again, until it's all settled? or is something else going on? think I'm at least 6-8 adjustments now.. getting really good at setting the valve clearance and timing... but should I have to so often?

any thoughts?
-XSiveAl

gordo · Posted: May 28, 2009, 11:50 am Post subject: Re: Adjustments after rebuild

Alot of guy's here set the valve's warm.(100+ degree's) I set them warm, closer to 100 than warmer because I don't want to get burn'ed up too badly.You would think that the clearence would be less as they warmed up, but who know's. And no, maybe at every oil change reset the clearence. That's usually when you reset point's, timing, ect.On the retorque of the head, that should be done until the torque stay's the same, no more tightening.

yamaman · Posted: May 28, 2009, 1:23 pm Post subject: Re: Adjustments after rebuild

Some good info here on valve clearances and thermal activity:

www.motorcycleproject....clear.html

gordo · Posted: May 28, 2009, 3:55 pm Post subject: Re: Adjustments after rebuild

Very good, Yamaman. Forgot about that, as of lately I've been helping a friend with a race car, push rod motor. Thanx for the post. Gordo

jimmythetrucker · Full Member Joined: Mar 12, 2008 Posts: 1283

FWIW (which ain't much), a bit of trivia:

We had a factory rep from Toyota point out to us once that the 1600 cc Toyota hemi is not an overhead cam engine. "The camshaft lies below the top of the valve stems," he told us. He continued: "Lift is transferred from the camshaft to the valve stems by rockers, which also ride above the cam. The 1600 is therefore NOT an overhead cam (OHC) engine but a cam in head (CIH) engine."

This is to note that the same is true of the XS650 twin.

tacoswild · Posted: May 28, 2009, 7:21 pm Post subject: Re: Adjustments after rebuild

I'm afraid that sacred cow article might be a bit of a sacred cow itself. I went through a little discussion with that guy about it, and on his suggestion I spent a bunch of time pouring over webcam and megacycle's catalogs to see if his idea that "more valve lift = more running lash" held up but I wasn't convinced. There are a few bikes in the catalog where exactly that relationship holds true, but there are other models where no matter how much lift the cam has the recommended lash never changes and even some models where the opposite can be seen, a cam with more lift being run with less lash.

But maybe the most obvious argument against his idea was at the very beginning of the catalog he thought would prove it. This is megacycle's take on the issue:

III. VALVE LASH (also called running clearance, valve or tappet clearance)
For an engine to run properly the valves must close completely and seal well against their seats. For this reason, a certain amount of clearance or “lash” must be maintained in valve train. Just a thousandth of an inch would suffice, except that due to thermal expansion and contraction, some engine parts will change size more than others—thus the valve lash will change with the temperature of the engine. For this reason, most engines require at least several thousandths of an inch clearance when cold. Too little valve lash will result in loss of power, uneven running, over heating and burning of the valves and seats. Too much clearance will cause excessive noise and wear, and in the extreme will cause valve bounce or “float”—resulting in valve and valve spring breakage. There is usually a few thousandths latitude between tight and loose valve lash. An experienced mechanic can determine this range by careful experimentation. The clearance can be changed within the range to tailor the engine performance to a particular application. In general: More clearance will sharpen up the low and mid range and reduce top end. Please start by installing your cam with the valve lash settings listed on the timing card supplied with each Megacycle Cam. Adjust valve lash according to the application.

yamaman · Posted: May 28, 2009, 11:59 pm Post subject: Re: Adjustments after rebuild

Halco recommended 0.003" in & 0.006" ex on all models except XS1 XS2 which needed 0.006" in & 0.012" ex. Doesn't say hot or cold, but I'll go out on a limb and say in all likelyhood, cold!

650rider.com/index.php...c&start=24

A good oportunity for us all to learn a bit here Al, how about setting your lash as & how you choose. Then give us the cold & hot clearances!

What did you torque the head down at? The manual says 25 ft lb, most here seem to tighten them up to 30 ft lb. xsjohn goes up to 35 ft lb with never seize on the threads! I wouldn't bother going over the 35, but perhaps somewhere between wherever your at & 35 and it will settle down for you!

Tacos, I fully get what your saying. I agree the first & foremost reason for lash is to get an effective seal on the valve! And of course you can alter the state of tune with valve lash alone!

The differences between the heat effects on push rod & OHC engines was what I was trying to highlight!
I think when you start getting into high engine speeds, multi valves & more exotic materials, a lot of the old theories go flying out the door!

So I think that most of what he says is true in part, however you can't cover every eventuality with one statement! Even with zero clearance, the "ramp" will still exist!

XSiveAl · Posted: May 29, 2009, 12:34 pm Post subject: Re: Adjustments after rebuild

Thanks guys,

uch less stress about it now, I worry too much probably but, after all the work I've done I sure don't want to burn out my new seats and valves,.. or worse.

Yamaman...

that's a very informative article there. It makes a lot of sense that the clearance in the ohc.. or ihc as it is.. would become greater. I believe that's exactly what I'm experiencing as well. I set it up per the manual yesterday again and it runs great, sounds great, but when it gets hot it tics away.

I ran it good last night for nearly an hour.. first real ride.. performs very well, but still this ticking, particularily on the right cyl. will drive me nuts.

I'll leave it sit all day and check the clearance again cold, if it's changed, I will reset to spec, run it and then measure it again hot.

It makes more sense to me now to set everything while it's near operating temp.. that's where everything counts the most right?

Popular opinion and physics would suggest that the cam chain gets tighter when hot.. so it makes most sense to set the tension and timing at operating temp.. the book says do the valves cold.. it's too bad they don't offer a hot clearance spec. too, though..

It also makes a great deal of sense to me that every engine wears differently and that even new from the factory things can be out of spec. there's a lot of variables if you look too closely.

It may be wise to consider the specifactions as a guideline and that fine tuning may need a thou or two variance from manufacturers recomendations and probably even varies with each valve set-up.

I think I get it..
I'll experiment some more and post the results.

-AL

jimmythetrucker · Full Member Joined: Mar 12, 2008 Posts: 1283

Unless somebody knows otherwise, I assume the fix for noisy valves on the XS requires a set of Mike's "elephant-foot" rocker shafts.

Youngsters and newbies here may not realize that valve noise isn't due to expansion alone: the tip of the adjuster screw beats pits in the top of the valve stem, pits which add clearance between the tip of the adjuster screw and the valve stem, pits which also make the valves impossible to adjust accurately because your feeler gage cannot measure the depth of the pits.

Do away with the pits by doing away with the old adjuster screws, you've done away with one major cause of the noise.

Thanks to the guys on this site who tipped me about elephants feet. I never heard of them before I came here. I plan to get a set for my own machine when I have to tear the engine down.

XSiveAl · Posted: May 30, 2009, 11:45 am Post subject: Re: Adjustments after rebuild

Who you callin' a newbie!?

just kidding.. I'm only on my 2nd XS.. sold the first one.. outta stupidity about four years ago before I really learned anything useful.. spent the last few gathering parts.. from basket case to mental case in only three short years.,

I've seen some of the posts and pics about the vw adjusters.. looks like a great idea and I think I'll get them for my next teardown too.. but today I'm going to sort this out.

I will post the results.

just out of curiosity.. are there some tricks to determining the condition of the rocker arms.. Yamaha manual says where they wear typically... but not how to measure that wear.

-Al

XSiveAl · Posted: May 30, 2009, 4:02 pm Post subject: Re: Adjustments after rebuild

okay... so I have retorqued the head nuts for the 3rd time and found only two below spec, while I had the ignition down I installed a new point cam... greased cam shaft.. reset timing and lastly have checked the clearance again at cold.

bear with me.. I'm metric.

left side intake.. still where I left it at 0.010
right side intake.. tightened to less than my smallest feeler gauge 0.007 -
reset to 0.010

I will run it for a bit and check the clearance again hot.

-Al

XSiveAl · Posted: June 1, 2009, 12:50 pm Post subject: Re: Adjustments after rebuild

Ran it til it was good and hot.. just barely able to get ahold of the tappet covers.. and checked the clearance.

this time the left and right sides had both widened. the right though still larger than the left. and still noisier. By my best guess.. and guages. the left became about 0.012 and the right, larger, between 0.012 and my next size up 0.015 (i need more feeler guages)

so I set them to a loose 0.010 at nearest to operating temp. I could stand.. just a slight drag. and locked 'em in. It's perfect. I can still hear the rockers and valves, so I know they're not hung open, both sides sound smooth and equal and the bike performs very well. starts easy, runs well cold and hot.

On top of that, may be coincidence, but now three times heating and cooling and it's holdin a tune.

So, best as i can tell, at least for my bike as it stands after the rebuild, that the specifications are a good place to start.

I will check it cold again and post and then again at the end of the week.

-AL

pamcopete · Posted: June 1, 2009, 2:40 pm Post subject: Re: Adjustments after rebuild

XSiveAl

Well, of course valve lash is important, but the symptoms you have could also be caused by low oil pressure and/or using the wrong oil, both of which would be worse when the oil is hot.

The other possibility is a partially blocked orfice in the oil feeder tube to the head, especialy with a rebuilt engine with all that junk floating around.

You can check the oil pressure by drilling and tapping a hole in the round oil screen cover and connecting a 0 to 30 PSI gauge there, either permanently or temporaily. If tempory, then just get another cover for the screen to get rid of the hole.

Oil pressure should be between 3 and 8 PSI with the engine hot @3,000 RPM. Don't be fooled by the initial cold pressure of up to 15 PSI

XSiveAl · Posted: June 1, 2009, 5:42 pm Post subject: Re: Adjustments after rebuild

Pamcopete,

I had considered that momentarily but I don't think that's part of my problem. I hope not. Of course, If the top end isn't cooling properly it would definitely cause problems like those and then quickly get much worse.

I've got a couple spare filter caps.. why not install a pressure gauge?

I am currently using by R.G's recommendation in "oil, the last word?".. castrol gtx diesel 15w40... he makes a good argument in the debate. And due to a sinking float, I've changed the oil three times since I rebuilt less than 400km ago, I think if there's any junk floating around big enough to block the flow in the oil tube.. that I would have bigger problems now... but it could be and won't take much to remove it and check it out.

should i be running something else in my 78E, is the castrol ok?

It had crossded my mind as well that maybe the difference in valve clearance somehow is relative to the replacement guides I had the machinist install? don't think that it should be if he did it right, though.

XSiveAL

xsjohn · Posted: June 1, 2009, 5:56 pm Post subject: Re: Adjustments after rebuild

If this is stock cam and valve springs..........which I assume be because you didn't mention changing the cam....or at least I didn't read it......clearance 6 exhaust and 4 intake cold (thousands)........and from my experience the only way to truly quiet the intake valves when it's hot is to add some oil to the valve tips............never hear mine at all after that was taken care of a couple of years back..........

And the terms....guiet and high performance are usually always an oxymoron.........

xsjohn

pamcopete · Posted: June 1, 2009, 6:06 pm Post subject: Re: Adjustments after rebuild

XSiveAl

Well, the choice of oil is a very personal issue, and I don't doubt that RG has had good results with the Castrol Diesal 15W40, but IMHO, that is too light an oil for these hot running XS650's.

y personal choice is Pennzoil 20W50.

As for an oil pressure gauge, if I had just spent $$$ and my time rebuilding an engine, I would certainly want to know what the oil pressure is. If it is higher or lower than nominal, then I would check it out, because unlike automobile engines, the oil pressure is not influenced by new bearings as the bearings are either ball or roller, but the increased friction from the new parts will tend to create more heat, thus necesitating a heavier oil.

(where the hell is the spell checker on this site?)

jimmer · Posted: June 1, 2009, 6:36 pm Post subject: Re: Adjustments after rebuild

(where the hell is the spell checker on this site?)

I digress but since you asked ... use Firefox ... and enable 'check my spelling as I type' end of problem

nudude53 · Posted: June 1, 2009, 6:44 pm Post subject: Re: Adjustments after rebuild

The first thing I would check would be that oiler pipe fitting, there's bound to be some junk in that hole that missed the filters. Check the banjo bolts too.

IAmGrowler · Posted: June 1, 2009, 6:53 pm Post subject: Re: Adjustments after rebuild

pamcopete wrote:

XSiveAl
(where the hell is the spell checker on this site?)

Speeling is hily overated and best left to the yung pups trying to win intrance into hily overated collagens, universitees and udder placec of hier edjumacation.

Yestidy I couldnt speel Mastr Plumbr -- And now I are wun.

XSiveAl · Posted: June 2, 2009, 11:55 am Post subject: Re: Adjustments after rebuild

pamcopete,
that's sure sound advice and I will do. I like how the bike's running now and I'd like to maintain it and and continue to improve on it. Installing an oil pressure guage seems much easier than tearing it all down again before I should have to.

I will check the oil delivery pipe before I ride again just to be sure. I can probably pressure test it by attaching a hose from a small squeezable oil container to the bottom of the oil delivery tube.

and just for clarity, when you say pennzoil 20w50 you mean their 20w50 specifically for motorcycles, right?

clearance values:
imp. met.
0.004 = 0.01016
0.006 = 0.01524

-AL

XSiveAl · Posted: June 5, 2009, 11:17 am Post subject: Re: Adjustments after rebuild

pampcopete,.. a follow up.

after weighing your suggestions, I removed the oil feed tube and very easily determined it was clear of blockages,. checked banjo bolts - also fine... retorqued headnuts,.. rechecked cam and clearance and timing..
restored to specified clearance values.. 0.010 in. 0.015 ex (metric)

and changed the oil to the recommended 20w50

I could not find penn 20w50 for autos in any of my favourite parts suppliers but I did find pennzoil 20w50 for motorcycles and am trying that.. after looking at some oil charts I realized that in places it may stay cool enough for most of the year for 15w40.. may be good for spring/fall but, here on Vancouver island it's already too hot for it.

thank you. on day two it runs noticably cooler and quieter, responds better,.. valves sound great now.. a little clatter.. but probably quieter than a lot of them.. smooths right out just over 2000.

A reminder that you should always look at the simplest things first.. before overcomplicating stuff or trying to solve problems that aren't there to begin with. I hope I didn't do any irrepairable damage in the 100Km I ran it tight. I'm going to keep an eye on the clearance for the next week or two just to make sure it's all settled in. A little more research and I've found it suggested that after valve and guide replacement a little change may be expexted inside the first 500 - 1000 Km and shouldn't be any worry, just to keep watching it and adjust when necessary until it setttles.

this is my 7th bike in ten years (my second XS) and, as of yesterday, it is by far the best working street machine I've ever had.

thanks again,
-XSiveAl

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