Oil Cap blowing off!!

Drewv1

Drewv1

Member
I've got an issue that I hadn't paid a whole lot attention to the past month or so but now I'm getting ready to head out to Street Vibes next weekend and need to have the bike it shape.
My oil cap is constantly blowing off when the engine revs high. Generally, when I fire it up, the cap will actually shoot off about 3 foot in the air if I have given the throttle a half twist before starting. I put it back in, rev a few times and it seems fine but when I get to my destination, its laying on the battery again.
I'm not a mechanic but I would assume something is clogged and not allowing it to breath properly. Are there any vent hoses I should be checking or anything that should be cleaned with regular maintenance? Bike is an 04 Chopper with a 107, everything stock on motor.
I hope this is something simple but I'm not sure of where to start.
Thanks
 
chacha

chacha

Chaff Your EHC!!
Calendar Participant
check the vent hose from the crankcase to the back of the air cleaner.....something is blocking the breathing of the motor and it's finding the weakest point to escape.
 
imthewildman

imthewildman

Member
I had sort of the same problem, but I have a screw on cap so it didnt fly off, but the seals on the push rods kept blowing out, the reason was there was a plug where the crankcase vent line was suppose to go, came that way from the factory, it started after 5 thousand miles, then went from bad to worse, after I installed a vent line then it quit, plus, according to the manual, it shows a screen filter on the pump, it needs cleaned at every oil change and Ive been told if it plugs then the crankcase can build extra pressure (dont hold me to that, its just hearsay, but I still do it just in case). one more thing, a friend of mine went and got an oil change, they put way too much oil in it, blew oil outta every gap the pressure could find, drained oil, put right level in and presto, no more leaks.
Just remember, just cause a guy has a job at a shop, that doesnt mean hes a mechanic.
 
Kodiak

Kodiak

Member
imthewildman said:
I had sort of the same problem, but I have a screw on cap so it didnt fly off, but the seals on the push rods kept blowing out, the reason was there was a plug where the crankcase vent line was suppose to go, came that way from the factory, it started after 5 thousand miles, then went from bad to worse, after I installed a vent line then it quit, plus, according to the manual, it shows a screen filter on the pump, it needs cleaned at every oil change and Ive been told if it plugs then the crankcase can build extra pressure (dont hold me to that, its just hearsay, but I still do it just in case). one more thing, a friend of mine went and got an oil change, they put way too much oil in it, blew oil outta every gap the pressure could find, drained oil, put right level in and presto, no more leaks.
Just remember, just cause a guy has a job at a shop, that doesnt mean hes a mechanic.
Click to expand...
I think I have the same problem on my 04 Chopper. At first I just noticed that every time I took the seat off my oil cap was laying on one side or the other of the filler neck. The cap is just a push in kind and fits really loose, I thought it just might be bouncing out as I rode. Now that I changed the oil for the first time and have the level up to where it should be I noticed it leaks every time I got off the bike and put in on the side stand. The oil looks like it is coming from the filler neck (spashing out I guess) then running down the side of the oil tank and dripping on the rear belt and then ending up on the ground right by the side stand. I was just going to get a tighter fitting cap or rig this one not to come out so easily, but after reading this thread I am worried about blowing the seals on the push rods. Is that screen on the oil pump your talking about the same thing as the tappet screen/hydraulic lifter oil filter screen? And I suppose once I get a chance to look at my bike the breather hoses will be obvious and easy to check.
 
mobsta

mobsta

Well-Known Member
hey bro,not sure you have the same problem but,my 04 was doing the same thing.cap was laying on tank.it was loose fitting.i put a harley cap on it about 2 years ago.not a problem since:cheers:
 
Kodiak

Kodiak

Member
Had my seat off the other day and started the bike up. As soon as the engine fired the oil cap shot off like a cork and landed back behind the rear tire. Really impressed my Dad who thinks if its not HD its crap.
 
imthewildman

imthewildman

Member
hey kodiak, the screen Im talking about is on top of the oil pump, mine takes a flat head screw driver to take out, mine is an 06 and I dont know if the 04 even has one, maybe someone will chime in and let you know.
 
G

Gas Man

Cool isn't cheap
Calendar Participant
I would start with checking the tappet screen then pulling off the oil lines and checking for debris.
 
cheffrey3d

cheffrey3d

New Member
I am having the same issue on my '04 117, I saw Gas Man posted some pretty good photos in this forum on cleaning the tappet screen. Forum-Techincal: How to: How to service your Big Dog. I already know what I will be doing tomorrow morning.
 
Kodiak

Kodiak

Member
Man!! I can not get that flat head bolt out that holds the tappet screen in. I borrowed a huge flat head screw driver from work and the damn thing is in there so tight it started to mash the head as I torqued on it. I had all my weight down on it as I turned it too. I am going to have to take it to the dealer or get creative with some leverage somehow. I did get a tighter fitting oil cap today, will have to see what happens now. A lot of bad weather is coming starting tomorrow so I don't see much riding in the next week.
 
mobsta

mobsta

Well-Known Member
wrong bolt i think bro.should be the hex head bolt.the owners manual shows the wrong bolt for the 04.thats the way it is on my 04 107.take another look:cheers:
 
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