Valve Adjustments - Why?

[JCH]

Damn.... I was really holding out hope that it might be the valves,  

This has been such a horrible experience for a new rider... all I want to do is ride and be confident in my bike   I have no idea what to do now.   I'm defeated.

Srinath, thank you for all of the help you've given me.  I do sincerely appreciate it.

[The Buddha]

Why dont you send me your carbs ... Trouble shooting is free ... Its 89-00 style right ... I know those much better ...
Cool.
Srinath.

[JCH]

Srinath,  its a '00.

The shop said they'd do a valve inspection for free, as soon as I suck what I can from them without paying anymore I'll send you my carbs.   Thanks for the offer!

[hairball]

any update?  one way or another, you're getting back on the bike!

[JCH]

I don't have anyone to help me load it on the truck  

I'm going to drop it off on Sunday I think when my Dad comes to visit  =[

[The Buddha]

You're going through a lot of pain for nohting ...
Runs great for 2-3 hours and suddenly craps out at 85 mph and loses power and dies doesn't sound like valves at all ... valves will first misbehave as the bike is started when cold and 2-3 seconds after startup they'll misfire and want to stall, ignore that phase and starting itself will be a bear, after that it will also misbehave till the thing gets fully hot ... after whihc it will misbehave at low rpm even after hot ... and that will increase and increase ... so in short if its crapping out at 85 and its the valves ... you'll never make it to 85 ... cos  its going to have burned up long before that symptom comes up at 85 ...
Cool.
Srinath.

[JCH]

That's probably true, but if theyre willing to check them for free why not   :dunno:    I know they haven;'t been adjusted in at least 4000 miles.

It just seems so weird that its the carbs.  She was running like a raped ape before she crapped out.  I did notice that there was some whitish lookinhg smoke (looked like steam maybe?) that was rising from the engine when it crapped.  But I don't know if thats normal.  It also backfired before dying the second time.

[hairball]

JCH, I sent you an email.  Get 'er done!

[Rema1000]

Valves being loose actually are going to have to be very very lose before they'd affect performance ... <...> Now being tight ... even a little will create misery very very quickly.

So the consensus is that it's better to run a little loose, than a little tight?  I just tried a valve adjustment today, and had one intake valve, and both exhaust valves, where the 0.0381 mm feeler gauge didn't fit (but I could still turn all the buckets).  But in all three cases, if I dropped one size, then the big 0.0762 mm feeler gauge did fit through.  

Without finding some odd-sized shims, I will have to risk being either a little too loose, or a little too tight.  I guess that if I use the thinner shims, then clearance is somewhere between 0.0762 mm and 0.0881 mm.  It would be easier to tell with a couple of these feeler gauges:


In Kerry's video, he suggested that although his intake valve was a little tight, he was going to leave it.  Are intake valves safer to run a little tight?

[cummuterguy]

JCH   I don't know if it will help you, but I once had a similar problem, on a different bike.

I could ride just fine for an hour, maybe longer, then lost all power. Would crank, put not attempt to start, once cooled down, it would start up just fine.

It ended up being one of my coils. when it was cold, it worked fine, but it would internally short once it was warmed up.

I found this by testing for spark right after it died. (I took an extra spark plug with me, when the bike died, i removed the plug wire, attached the extra plug and then just rested it on the valve cover to ground it.

Lo and behold, two new coils later, no more problems. (I replaced both cause I didn't see the point of waiting for another breakdown to replace the one that hadn't failed yet)

Don't know for sure that you have the same problem, but at least the testing part of it is free....

[The Buddha]

That electrical gremlin - That happened on my 89 at 35K ... but instead of an hour it will die on 1 cyl in 15 mins ... turned out to be crank trigger.
On valves ... Loose will be noisy even if its just at the high end of the clearance. Tight valves will start affecting in this order ... the 3 seconds after start up to full temperature - Warm up - followed by startup and warm up  followed by all the time. You'd not be able to start it and keep it running long enough to do damage if they are too tight. So The chance of burning a valve will be very slim. You'd have to be stupid to not notice that the bike has gone from starting with 1st or 2nd hit of the starter to start - die, Start - Die, Start - Die ... like 10 times and after it does stay running ... you'll have to blip the throttle constantly till its fully hot ... and it takes much much longer to warm up ... once warm it will run great till it gets shut off ... Happened on mine ... not GS my Virago ... So I run it tight and never let it come to that point ...
Valve clearances increase when fully hot atleast on a GS ... so tight when cold = Less tight when hot. However they do not evenly increase because the motor does not evenly heat up. I believe valves will get most of the inital heat ... exhaust especially, slowly it dissipates heat into the head, once they are all at temp Aluminum in the head expands more than steel in the valve. So the distance from cam shaft to valve seat is going to increase with the valve stem length increasing a bit less being steel. Alumium has 3 times or so the thermal expansion of steel right ... or is that 3 times the density for steel ... OK help someone ... Anyway its going to increase by a few nano meters ...
Cool.
Srinath.

[The Buddha]

[Kerry]

I guess that if I use the thinner shims, then clearance is somewhere between 0.074mm and 0.088 mm. It would be easier to tell with a couple of these feeler gauges:

Are you talking about measuring that particular clearance range, or about general valve clearance adjustment checks?  I ask because the thicknesses for those blades are in thousandths of an inch, which translates to "mostly too big" in metric:

.002 - .003 in =  .05 - .07 mm
.004 - .005 in =  .10 - .13 mm
.006 - .008 in =  .15 - .20 mm[/list:u]

In Kerry's video, he suggested that although his intake valve was a little tight, he was going to leave it.  Are intake valves safer to run a little tight?

That was just a "gut feel" statement on my part.  The way I figured it, exhaust valves ALWAYS have hot exhaust gases flowing past their edges, whereas intake valves usually have a cool air/fuel mixture flowing past them.

I'm sure that it's not good for either kind of valve to be tight, but given the number of way-too-tight exhaust valves I've seen ...  compared with maybe one or two slightly-too-tight intake valves, I "reasoned" that changes happen more slowly to the intakes.

[treybrad]

Well. I'm eager to swap out some shims this weekend after reading this. I checked mine a couple thousand miles ago and I know they were proabably too tight (my .038mm feeler wouldn't fit, but I could spin the shim..). Anywho, I've since gotten a valve tool, calipers and smaller (.030mm) feelers so I should be set.

It's encouraging reading this, my startup routine has gotten to be more of a hassle and gas mileage keeps dropping slowly it seems. It'll misfire and generally be a pain if it's cold out... almost like the choke isn't on all the way. Once it's "warm" but not "hot" like when I pull out of the lot from work it's kinda sketchy sometimes. Like.. when I shift into the next gear up it'll hesitate a second before the power comes back. Once it's warm no probs, so hopefully this is the valves and the uneven heating.. we'll see.

trey

[Rema1000]

I guess that if I use the thinner shims, then clearance is somewhere between 0.074mm and 0.088 mm. It would be easier to tell with a couple of these feeler gauges.

Are you talking about measuring that particular clearance range, or about general valve clearance adjustment checks?  I ask because the thicknesses for those blades are in thousandths of an inch, which translates to "mostly too big" in metric

Oops, I was thinking those were 0.02mm, 0.03mm, etc.  That's what I get for trying the valves for 2 hours, in a cold garage, then GSTwinning before bed.  Must've been tired.

Trey, where'd you find a 0.03mm feeler?  That'd be handy.  I've seen ads for metric feelers down to 0.04mm, but not 0.03mm.

[treybrad]

after watching eBay for months I finally found one... it's made by a german company. I'll find the seller name if you like, he may have more..  :dunno:

trey

[Kerry]

Download this PDF file of a page from the KBC Tools catalog.  (Thanks to tmckay for his old Found a 0.025mm Feeler Gauge online! Woohoo! post.)

Check out the individual feeler blades listed in the lower left-hand corner of the page.  They offer a (pretty pricey) .001" blade, which is about .025mm.  What we really need is a .0012" (.03mm) blade, but I have never seen one yet.

[se7enty7]

Download this PDF file of a page from the KBC Tools catalog.  (Thanks to tmckay for his old Found a 0.025mm Feeler Gauge online! Woohoo! post.)

Check out the individual feeler blades listed in the lower left-hand corner of the page.  They offer a (pretty pricey) .001" blade, which is about .025mm.  What we really need is a .0012" (.03mm) blade, but I have never seen one yet.

isn't .0015" equal to .038?


that's good enough for gov't work imo

[Kerry]

isn't .0015" equal to .038?


that's good enough for gov't work imo

So, if your .0015" / .038mm blade won't fit, you'll replace the shim with the next thicker size?  That could change the clearance from an acceptable .037mm to an off-the-loose-end .087mm.

I wish we could buy "half sizes".  :x

[treybrad]

Well in case anyone wants some of the .03mm feelers, here's the auction I won:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=4524229680

You could msg him and see if he has more, or.. looks like they have a website too...

http://www.samstagsales.com/

just an fyi

trey