I pasted the wrong title. Sorry, this is about a leaking valve.

I have my heads off while doing new base gaskets. I checked my valves by pouring water in the intake port and then the exhaust ports and then watching to see if water seeped out from behind the valves. Looks like I have an exhaust valve that is letting a trickle of water escape.

I yanked the springs and lapped the valve hoping for a better seat. Before putting the new seal and stock springs back in I filled up the exhaust port again and I still have a trickle of water coming from behind the valve.

Where do I go from here? Do I try more lapping? I used permatex valve grinding compound 34A. Is a small exhaust leak something I can live with for awhile or is it a must fix immediately kind of thing? Do I just put it all back together and ride it?

I am not in a position right now to just send them off to a machine shop and say fix it. Next summer I planned on pulling the heads again and having some work done to them, but I can't right now.

I'm looking for opinions on options. Thanks.

 

Needs fixing, try using a coarser grinding paste and then the fine one to clean it up....check the valve itself for any black marks on the ground surface.....these are pits and they have to be gone before the valve will seat....if you don't fix it it will only get worse.

 

Go find and older shop and have them tru up all the valves and lap em in again. Cheap down and dirty. Used to have to do the ole pans shovels sportsters ever couple years back in the day. Cost nothing. But i think i would do a good valve job if i had it all apart. Cash is tight i know.... Make sure you put the springs on before you fill the port.

 

That sucks! That's why I had to send mine off to get fixed...AND it was the exhaust valve too! But mine was a busted exhaust valve guide though. But like Spanner and bumpandrun said, need to get it fixed befor you put it back together, or you will have to tear it apart again. And if that valve decides to go south, byby piston!

 

thanks for the replies. I know I cant put it back together like this. That was a momentary lapse of patience talking. I'm so close to riding I can smell it. All these things popping up and slowing me down is killing me. lol

I was wondering if putting the springs back on would make a difference. I was just holding the valve in place with finger pressure when it leaked after I lapped it. Maybe the pressure from the spring would hold it from leaking?

I'll try that.

Junglejoe, what did it cost to get your fixed? What did they do to the heads?

 

Yea bro, definatly need that spring on there for sure!! That "may" be why it leaks, not enough pressure. As far as my heads, I decided since I am in it this far, I had bigger valves and port and polish done too! $600 freakin bucks!OUCH!!!! BUT, I had a local indy tell me about 100-150 to fix BOTH heads befor I decided to do all that other chit to them..

 

Its better to use gas than water to do the test as water can corrode a valve guide overnight if not cleaned up.

 

or alcohal...but not the kind you drink..lol

 

I was talking to an indy today and he said to use gas. He said gas will somehow get into place that water can't. He also said what others have posted about testing the valves with the springs installed. It was a duh moment for me. Of course I should have tested it with the springs installed. They are like 160 pounds of tension while using my fingers to hold the valve is definitely not. Oops. Live and learn. I will retest it with springs tonight.

 

Be sure not to " overdo " the lapping thing as its a procedure designed to
simply smooth out any very slight imperfections and you must be certain that ALL of the paste material is removed before checking.
Check the valves with a magifiying glass to look for pitting or anything unusual.
Most valve wear occures in the guides and the cheapest way to check them is with your own fingers . Install the valves into the guides and try to move them back and forth axially with the tip of your finger . If you feel any movement at all replace the valve guides and seals .