Author Topic: Would you notice a stuck/sticky valve when adjusting tappets ?  (Read 1528 times)

0 Members and 1 Guest are viewing this topic.

Offline greenjeans

  • Industrial strengthed dreamer.
  • Old Timer
  • ******
  • Posts: 2,962
  • 1972 CB750K2
1969 CB750K

Wouldn't you ?     When you check them with the gauges, the valves are closed fully correct ?
Also - to get a feeler gauge in there the tappet has some give/wiggle - closed valves.   If they are open there should be no movement/wiggle to the tappets ? correct ?

Still have a warm #3 pipe.   Getting spark.   Carbs have been cleaned thoroughly - although I'm starting to think I'm going to go through them again.   

I'm at a loss here. 
Yep, I'm the kid that figured out how to put things back together...eventually.

Offline dave500

  • Really Old Timer ...
  • *******
  • Posts: 17,022
  • WHAT?no gravy?
Re: Would you notice a stuck/sticky valve when adjusting tappets ?
« Reply #1 on: March 16, 2012, 09:51:55 PM »
the valves are closed,there will be some wiggle or the feeler wont go in,if the valve is sticky or stuck slightly open the wiggle will be more,a leak down test is best if you think you have a sticky valve,even just hook up an airline into that cylinder,you might not notice a sticky valve depending on where its stuck or sticky?so what symptoms are you worried about?
« Last Edit: March 16, 2012, 09:53:35 PM by dave500 »

Offline Terry in Australia

  • Really Old Timer ...
  • *******
  • Posts: 33,321
  • So, what do ya wanna talk about today?
Re: Would you notice a stuck/sticky valve when adjusting tappets ?
« Reply #2 on: March 17, 2012, 03:30:18 AM »
Yep, +1 on what Dave just said, have you done a compression test mate? Could be that you've got a burned exhaust valve. Cheers, Terry. ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline dave500

  • Really Old Timer ...
  • *******
  • Posts: 17,022
  • WHAT?no gravy?
Re: Would you notice a stuck/sticky valve when adjusting tappets ?
« Reply #3 on: March 17, 2012, 03:56:17 AM »
if a valve sticks or dosent seat fully itll burn,or if the tappet is way too tight and it rides,its like an oxy cutting torch blowing over the bad seat area if its the exhaust one,a chuff chuff from the inlet if thats the culprit,youll have a bad misfire feel and real low power.
« Last Edit: March 17, 2012, 03:58:20 AM by dave500 »

Offline greenjeans

  • Industrial strengthed dreamer.
  • Old Timer
  • ******
  • Posts: 2,962
  • 1972 CB750K2
Re: Would you notice a stuck/sticky valve when adjusting tappets ?
« Reply #4 on: March 17, 2012, 08:37:39 AM »
well - I'm on the original tires (the new ones should show up this morning.)      This thing fires right up an idles well.  It does not seem like there is lost power - although I really haven't pushed it too much for fear of the tires shredding.    It does seem like there is some sputtering/missing, but it seems to catch itself and accelerate like a bat-outta-hell.   

When I set the tappets originally, most of them were dead on - didn't need much adjustment at all.   

Coils, wires and plugs are new.  Carbs cleaned thoroughly, floats set.  Getting gas.  Getting spark. 

Guess I'll go find a compression checker and see what happens.

The symptoms that I have are an exhaust pipe that is warm to hot  -  not nearly as hot as the others.  The #3 pipe also has much more pressure coming out of it a scompared to the others.   (pipes are brand new HM300s)

Yep, I'm the kid that figured out how to put things back together...eventually.

Offline markb

  • When I finish my current project I might be a
  • Master
  • *****
  • Posts: 1,615
Re: Would you notice a stuck/sticky valve when adjusting tappets ?
« Reply #5 on: March 17, 2012, 12:27:52 PM »
For what it's worth, on my K0 I had one cylinder that ran cooler than the other three and the plug kept fouling out.  It ran good until that happened.  New plug and it ran great again for 50 miles or so.  I did all the usual stuff, carbs, etc., and finally tore it down to the case a year ago.  Couldn't really see anything that would cause it but had a valve job done while I was at it.  The engine only had a few hundred miles on it since the previous rebuild so I used the same rings and pistons with honing.  Didn't do anything else except put it back together and the problem went away.   
1969 CB750 sandcast #97 restored - Sold Restoration thread link
1969 CB750 sandcaxt #576 - Sold
1969 CB750 sandcast #1553 - Sold
1969 CB750 sandcast #1990 - Sold
1969 CB750 sandcast #5383 restored - Sold Restoration thread link
1970 CB750 K0 restored - Sold
2010 H-D Tri Glide Ultra Classic (Huh?)