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jacksondee
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Joined: Jul 30, 2013
Posts: 302
Location: Chicago

PostPosted: Sun Jun 15, 2014 9:13 pm Reply with quote Back to top

Heh. Think I have a little problem that needs fixing here?

Image

This is from a broken cylinder head cover bolt. I am going to remove the whole thing tomorrow and take it to a machine shop to get the busted bottom half of the bolt out, if I can't drill it from the bottom. I was unsuccessful drilling it out from the top. That hot oil leak feels good on my leg!

Seriously though, can an F not have a cute little crankcase breather? I have pods on my bike via Melchiro's jetting for pods. This breather also seems to be leaking heartily, right through the filter on the breather, oil all over the crankcase. I saw one picture of a guy who ran the stock tube from the crankcase into one of his pods, so what made it up the tube was sucked back into the carb similar to the stock set up..

The bike does seem to have just a little too much oil in it as I have over compensated with extra oil the past 2 weekends while dealing with the leaky busted cylinder head bolt, and still trying to ride it here and there. Is that contributing to the super-leaky crankcase breather?

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genesound
Red CB1100F
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PostPosted: Sun Jun 15, 2014 9:18 pm Reply with quote Back to top

What's your compression like then? It shouldn't really be blowing out of there pell mell, just a bit of blow by. I usually Y the two breathers and run a hose across the top of the case and bend it down towards the ground. You can put a little pod filter on it if you like, but the primary thing is to not let water get into the cases.

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jacksondee
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Joined: Jul 30, 2013
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Location: Chicago

PostPosted: Sun Jun 15, 2014 9:29 pm Reply with quote Back to top

genesound wrote:
What's your compression like then? It shouldn't really be blowing out of there pell mell, just a bit of blow by. I usually Y the two breathers and run a hose across the top of the case and bend it down towards the ground. You can put a little pod filter on it if you like, but the primary thing is to not let water get into the cases.


Thanks Gene. Last checked the compression was low. This was prior to getting all the valves set at .006 though. I didn't check post-valve shim adjustment, because I was just so darn excited to try and fire her up. When I take the cylinder head cover off again either later tonight or tomorrow I'll check compression again.

Would low compression contribute more to this? Or high? When I did last check prior to adjusting valve shims, I was at ~90 on every cylinder, which I know is super low..

Image

look at the slick on the crankcase and the little pools of oil to the 'front' of the breather

Image

I do have the fatter crankcase breather hose, the one that's right next to the dipstick, running directly into the 'collection' box under the battery. I did not remove the stock 'collection' box under the battery case. Its only the smaller of the two crankcase breather hoses that I have the cutesy little K&N red breather on..

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jacksondee
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PostPosted: Thu Jun 26, 2014 1:13 am Reply with quote Back to top

Its still leaking real good.

I checked the dipstick after riding a bunch today and oil level seems to be at maximum. Has it possbily been hyperactive because I had maybe a bit too much oil in there?

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Grumpy32
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Joined: Jul 05, 2008
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PostPosted: Thu Jun 26, 2014 3:59 am Reply with quote Back to top

You ride a motorcycle wearing shorts. Rolling Eyes Razz

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Terry

07 cb 900f hornet 919... the fastest Red one. 
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1100russ
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Joined: May 17, 2010
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PostPosted: Thu Jun 26, 2014 10:09 am Reply with quote Back to top

Grumpy32 wrote:
You ride a motorcycle wearing shorts. Rolling Eyes Razz


Yep. Wink Twisted Evil
 
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jacksondee
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PostPosted: Thu Jun 26, 2014 1:05 pm Reply with quote Back to top

Grumpy32 wrote:
You ride a motorcycle wearing shorts. Rolling Eyes Razz


One of my responsibilities at work is being a dog walker. You go to one house, walk the dog around the block 20 minutes, go to the next house and walk the dog, etc. I'll do 7 to 12 of those per day. During riding season it's a blast going from house to house on the bike, zipping around the city. When it's hot as hell out, I have to wear shorts or I'd die of heat exhaustion during the walking part and the dog would most likely get really bored wondering why I collapsed on the sidewalk still holding it's leash, and it would eat my corpse..

I don't want to get eaten by a dog, so I wear shorts. Wink

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1100russ
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PostPosted: Thu Jun 26, 2014 1:22 pm Reply with quote Back to top

jacksondee wrote:
Grumpy32 wrote:
You ride a motorcycle wearing shorts. Rolling Eyes Razz


One of my responsibilities at work is being a dog walker. You go to one house, walk the dog around the block 20 minutes, go to the next house and walk the dog, etc. I'll do 7 to 12 of those per day. During riding season it's a blast going from house to house on the bike, zipping around the city. When it's hot as hell out, I have to wear shorts or I'd die of heat exhaustion during the walking part and the dog would most likely get really bored wondering why I collapsed on the sidewalk still holding it's leash, and it would eat my corpse..

I don't want to get eaten by a dog, so I wear shorts. Wink


roflmao
 
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SteveG
Silver CB900F
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PostPosted: Thu Jun 26, 2014 6:31 pm Reply with quote Back to top

Ok, Dog Walker, good excuse, but you would still scrape off mega-skin in the event of an event.

But about the oil spray, you say that the big hose is attached to the collection box under the battery? That hose, and the hose that is supposed to be where you have that filter, are supposed to join together and then connect to the top of the airbox (that you don't have), which creates a vacuum in the hoses which helps vent the crankcase. The way you have the big hose connected now is just like plugging that hose (assuming the hose coming from the collection box still has the plug in the end of it). That means all pressure from the crankcase has to come thru your vent filter. If you are slightly overfilled with oil, and have low compression (ie possibly worn rings which lets blow-by put more pressure in the crankcase), you have the correct recipe for oil thru the vent filter. Disconnect the big hose from the collection box, make sure the oil level is correct (check on centerstand (or at least straight up and down on level ground), have motor warm, run it and shut off for a moment, and don't screw dipstick in), and I bet your spray goes away.

Steve

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jacksondee
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PostPosted: Thu Jun 26, 2014 6:31 pm Reply with quote Back to top

Seriously though, the oil bubbles right through the breather. Should I just scrap the idea of the breather and put the hose back on? Do breathers not work?

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jacksondee
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PostPosted: Fri Jun 27, 2014 1:05 am Reply with quote Back to top

SteveG wrote:
Ok, Dog Walker, good excuse, but you would still scrape off mega-skin in the event of an event.

But about the oil spray, you say that the big hose is attached to the collection box under the battery? That hose, and the hose that is supposed to be where you have that filter, are supposed to join together and then connect to the top of the airbox (that you don't have), which creates a vacuum in the hoses which helps vent the crankcase. The way you have the big hose connected now is just like plugging that hose (assuming the hose coming from the collection box still has the plug in the end of it). That means all pressure from the crankcase has to come thru your vent filter. If you are slightly overfilled with oil, and have low compression (ie possibly worn rings which lets blow-by put more pressure in the crankcase), you have the correct recipe for oil thru the vent filter. Disconnect the big hose from the collection box, make sure the oil level is correct (check on centerstand (or at least straight up and down on level ground), have motor warm, run it and shut off for a moment, and don't screw dipstick in), and I bet your spray goes away.

Steve


Ha, "in the event of an event"

Thats good..

What's worse, me in shorts? Or the silly mofo's I see riding around in SANDALS!? I don't get that at all... And I see it once a week.

Anyways ok I get it. Thanks for that Steve. Very good stuff. I just bought new oil for the season and I've been reluctant to put it in until I've solved this problem..

I saw a picture of one guy who just cut the bigger hose to like 4" long, sticking straight up right out of the crankcase. No little filter on the end of it. Then he had the smaller hose go into one of his pods. He had the oval shaped pods, and on the bottom part of the oval that has some extra room, he cut a hole for the smaller crankcase hose to run into. So its kind of sort of similar to the stock set up I guess. But I really don't want to buy an oval shaped pods because the 4 circular shaped pods that match are just so pretty.

I will investigate this as suggested tomorrow. I do have the fat hose running to the collection box, and the collection box is still plugged as you have assumed.

Thanks man. Cool

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norm
Silver CB900F
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Joined: Jan 13, 2010
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PostPosted: Fri Jun 27, 2014 1:20 am Reply with quote Back to top

Just run a hose out the back and pot a non return valve on it, legs will then stay dry
 
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Tdem
Black CB900F
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PostPosted: Fri Jun 27, 2014 11:56 am Reply with quote Back to top

You don't need a filter on it because it doesn't suck air in, unless you've got a problem. The hose is there to vent the extra gasses in the crank case that blow by the pistons. If there is oil bubbling out of there, you've probably got either too much oil in there or the hose isn't long enough. The hose is long because some oil does splash up the hose, but since it's long, it doesn't come out, it drips back down the hose into the case, and only the gasses get out. Just put the stock hose back on and tuck it up above your carbs, I have mine attached to the frame in it's close to stock position with a zip tie.
 
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jacksondee
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PostPosted: Fri Jun 27, 2014 9:40 pm Reply with quote Back to top

Thanks fellas. Made a few adjustments and all is well in my world. Crazy- if I plug the end of the bigger crankcase breather hose with the tip of my finger for just a second, the breather that's on the smaller crankcase hose starts to leak immediately. If I unplug, it stops immediately.

Very cool info, thanks for it everyone. Now I can finally clean her up with some degreaser and change the oil for the season.

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genesound
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PostPosted: Fri Jun 27, 2014 11:46 pm Reply with quote Back to top

Quote:
Would low compression contribute more to this? Or high? When I did last check prior to adjusting valve shims, I was at ~90 on every cylinder, which I know is super low..


Yeah, lots of blowing out the crankcase vents is indicative of bad rings. If the rings were sealing perfectly there wouldn't be any, but perfect never happens either.

On a new broken in bike, there shouldn't be any noticeable air coming out of the crankcase at idle.

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jacksondee
Hawk
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Joined: Jul 30, 2013
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PostPosted: Fri Jun 27, 2014 11:55 pm Reply with quote Back to top

genesound wrote:
Quote:
Would low compression contribute more to this? Or high? When I did last check prior to adjusting valve shims, I was at ~90 on every cylinder, which I know is super low..


Yeah, lots of blowing out the crankcase vents is indicative of bad rings. If the rings were sealing perfectly there wouldn't be any, but perfect never happens either.

On a new broken in bike, there shouldn't be any noticeable air coming out of the crankcase at idle.


Well, great. Can I make it through this season without doing new rings? I don't want to take the engine apart right now seeing as how its finally turning nice in Chicago and I've finally got her running after all of last winter's off-season upgrades..

I definitely feel air coming out of the fatter crankcase breather hose. Its gentle, but I do feel a little exhaust coming from there at idle..

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norm
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PostPosted: Sat Jun 28, 2014 12:25 am Reply with quote Back to top

Air has to go somewhere when pistons come down
 
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1337
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PostPosted: Sat Jun 28, 2014 3:23 am Reply with quote Back to top

norm wrote:
Air has to go somewhere when pistons come down


No. Two pistons rise while the others fall canceling out any positive pressure. That is not the issue here.
 
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norm
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PostPosted: Sat Jun 28, 2014 5:20 am Reply with quote Back to top

Yes but still one hell of a lot of air in there getting the crap beaten out of it and I would want to get out of there any way I could and a breather is the best way out
 
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