\\; Those umbrella valves in the middle rocker cover, what's there purpose and how important are they?
 \\; I had some work done at the area dealer \\;a \\;while ago, now I've lost compression in the rear cylinder. \\;When I started pulling it apart I see that they (the umbrella valves) are not there. Seems the mech at the dealer forgot/neglected to put them in. I'm sure that they have nothing to do with my current problem, but after seeing his mechanical IN-abilities at the shop, then seeing this, I just wonder what else he may have done or forgotten to do.
 \\; Thanks
 \\; \\; \\; \\; \\; \\;&n bsp\\; Delbert
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Delbert
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They are part of the engine venting system and yes they should be there. WHat work did you have done? [align=left]See Figure 3-7. On the piston downstroke, a mixture of crankcase[/align][align=left]air and oil mist is vented up the push rod covers (1)[/align][align=left]through a breather valve (2) in each inner rocker box section.[/align][align=left]The oil mist separates from the crankcase air, collects and[/align][align=left]passes through a small drain hole adjacent to the exhaust[/align]valve in the head where it eventually returns to the crankcase.
 \\;\\\\\\;
 \\;\\\\\\;\\\\\\\\\\\\\\;[align=left]Ring trouble[/align][align=left]Compression low on first stroke, tends[/align][align=left]to build up on the following strokes, but[/align][align=left]does not reach normal. Improves considerably[/align][align=left]when oil is added to cylinder.[/align][align=left]Valve trouble[/align][align=left]Compression low on first stroke, does[/align][align=left]not build up much on following strokes.[/align][align=left]Does not improve considerably with the[/align][align=left]addition of oil. Check for correct pushrod[/align][align=left]length.[/align]Head gasket leak Same reaction as valve trouble.
 \\;
I am not sure if removing those umbrella valves could cause a cylinder gasket or severe valve seal failure but I would call the service department at a different dealer and inquire to see if the dealer who did your work caused this issue.
__________________ 06 FXDLI
I don't know about anyone else but I now officially hate all politicians...
Thanks for the reply. I had a cam installation go horribly wrong when the cam \\;bearing fragmented when I used a low quality puller to remove it. Not sure if I got all the needle rollers out of the case, and not having a garage to work in, with my tail between my legs, I took the bike to the dealer to have the cases split to be sure all the bearings were out. I wondered about the umbrella valves because of thier location. The part of the middle valve cover where they should be, just sort of hangs out there with nothing directly underneath them.
 \\; \\; \\; \\; Delbert \\;
Static compression only depends on a couple things (not the breathers):
 \\;
1. \\; Piston moving up
2. \\; Rings sealing
3. \\; Valves closed during the compression stroke
4. \\; No leaks on head gasket / head / cylinder
5. \\; I guess no holes in the piston should be mentioned
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95"Big Bore,HD Flat Top Pistons, Andrews TW-26G ,
SERT, Feuling Super Oil Pump, Feuling Lifters
HD Adjustable Pushrods, Big Boyz Ported 9.5, FAT CAT 2in1
Static compression only depends on a couple things (not the breathers):
 \\;\\\\\\;
1. \\;\\\\\\; Piston moving up
2. \\;\\\\\\; Rings sealing
3. \\;\\\\\\; Valves closed during the compression stroke
4. \\;\\\\\\; No leaks on head gasket / head / cylinder
5. \\;\\\\\\; I guess no holes in the piston should be mentioned
 \\;
Yes, that I do know. But, my question is about those umbrella valves that seem to just hang out there in the middle rocker cover. From thier location I can't figure out what they are suposed to do. The fact that they were not reinstalled in my bike just makes me wonder if my other problems might be human induced. Like maybe he forgot to do something else, or maybe he lined up the piston rings all pretty-like. I'll know more about that tonight when I get the heads off her.
Static compression only depends on a couple things (not the breathers):
 \\;\\\\\\;\\\\\\\\\\\\\\;
1. \\;\\\\\\;\\\\\\\\\\\\\\; Piston moving up
2. \\;\\\\\\;\\\\\\\\\\\\\\; Rings sealing
3. \\;\\\\\\;\\\\\\\\\\\\\\; Valves closed during the compression stroke
4. \\;\\\\\\;\\\\\\\\\\\\\\; No leaks on head gasket / head / cylinder
5. \\;\\\\\\;\\\\\\\\\\\\\\; I guess no holes in the piston should be mentioned
 \\;\\\\\\;
Yes, that I do know. But, my question is about those umbrella valves that seem to just hang out there in the middle rocker cover. From thier location I can't figure out what they are suposed to do. The fact that they were not reinstalled in my bike just makes me wonder if my other problems might be human induced. Like maybe he forgot to do something else, or maybe he lined up the piston rings all pretty-like. I'll know more about that tonight when I get the heads off her.
 \\;
Umbrella valves are strictly for crankcase ventillation. No compression could also be a pushrod issue. Bent or broken?
__________________ 06 FXDLI
I don't know about anyone else but I now officially hate all politicians...
Yes, no compression in the rocker covers. \\; Just need to vent and drain any oil and/or oil mist that gets up there. \\; I sometimes leave off the rocker covers to see how the oil is pumping up there.
 \\;
Let us know what they find - this must be something drastic, as there is typically 160 psi on the stock engine. \\;
__________________
95"Big Bore,HD Flat Top Pistons, Andrews TW-26G ,
SERT, Feuling Super Oil Pump, Feuling Lifters
HD Adjustable Pushrods, Big Boyz Ported 9.5, FAT CAT 2in1
This bike has been sitting in the basement since June of 05. When I parked it I had only ridden it a few times since I’d had the work done on it. When I parked it, I pulled the plugs and sprayed the cylinders full of WD-40 and put the plugs back in. At that time I noticed that the rear plug was pretty nasty, it had some black fouling. When I pulled her out this year, I sprayed some more WD-40 in and cranked it over a few times before replacing the plugs. Monday morning I added some oil before heading to work. When I started the bike, it took a few more cranks than usual to fire. It seemed kinda rough and weak as it warmed up, but it hasn’t run quite right since I got it out for the season a few weeks ago. I headed for town to get some gas and it seemed ok on the highway, but when I got to town I saw some smoke coming up from the engine. I found that the oil cap had come off. I put it back on and it popped right back off. I thought I accidentally added to much oil, so I turned around and slowly rode back home. After she cooled I drained the oil down to the lower mark on the stick then I fired her up again the cap blew off as soon as I brought her up off idle. I checked the oil again and it was still at the lower mark. And she wasn’t running very good at all. Knowing the pressure pushing the cap off had to be coming from somewhere I decided to check the compression. Now I didn’t open the throttle when I cranked it over but I got almost 25psi from the rear cylinder and about 60 from the front. I knew something was toast!
 \\; I got her pulled down last night. As I took her apart I found several things that pissed me off. The aluminum mount for the front pipe clamp was broken-out around the screw holes. The screws were driven way to far into their holes. When I took off the bottom rocker boxes, some of the bolts were so tight I thought I’d need an impact to get them out while others were not much more than finger tight. The intake manifold clamp on the rear cylinder was broken in two. You can clearly see where the Allen heads were torqued so hard they cut right through the clamp. When I pulled the cylinders, I found both compression rings on the rear and one on the front piston were broken. No shocker there! The rings on the rear were not quite lined up with each other, but within about 3/8” of each other.
 \\; Did I just get a bad set of rings? Did they install new rings like they said? Did they hone the cylinders when they installed new rings? I’m sure I was billed for that. Did sitting so long cause it? I think they were going or gone before I parked it because of the way the plug looked. Well so many questions never to be answered. But now the big question is, since there is some light scoring in the rear cylinder, can I get by with honing the cylinder and replacing the rings, or will I need to buy pistons and bore it? I guess I’ll find out.
But I still can’t figure out what those umbrella valves do???
 \\;
 \\; \\; \\; \\; \\; \\;&n bsp\\; \\; \\; Delbert
Quick summary,, KBFXDLI has already explained the head breather valves (umbrella's)
[align=left]See Figure 3-7. On the piston downstroke, a mixture of crankcase[/align][align=left]air and oil mist is vented up the push rod covers (1)[/align][align=left]through a breather valve (2) in each inner rocker box section.[/align][align=left]The oil mist separates from the crankcase air, collects and[/align][align=left]passes through a small drain hole adjacent to the exhaust[/align]valve in the head where it eventually returns to the crankcase.
 \\;\\\\\\;\\\\\\\\\\\\\\;
The rear plug was dirty because the rings weren't properly lined up allowing oil blow by. The reason the rings broke are not clear for me by your statement,, you said you had been running the bike for a few weeks now but then that morning it started rough and then blew the oil dipstick out while riding to town, that can be from the broken rings if that happened at that point, blown oil cap is either blocked breather head or the compression from the engine past the broken rings and we know you have broken rings.
I have to say there seems to be something missing as far as info, but it doesn't really matter at this point, it's got to be fixed, get the heads checked out while it's down, make sure the valve train is good and there's no problem with carbon build up etc.,, fix the umbrella's,, check the clearances on the scorned cylinder, you might have to bore it, but it might hone out.
Obviously the mechanic who worked on you engine was not the best for sure,, but I'm not sure that he caused all of your problems, if he had broken the rings on install it would have smoked and had the low compression numbers right off the bat when you picked it up after the work was performed, and obviously you had run the bike a fair amount before storage if the plug was really dirty.
Good luck with it, it will run again just make sure when it's buttoned back up again everything is done correct and it should run like a champ.
Umbrella Valves
06 FXDLI 
