Blow-by question
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Cruiser
Joined: Jun 2012
Posts: 127
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From: So. California
Blow-by question
I posted this in the engine... forum, but didn't get any answers...1995 FLHR
This is a Sputhe 104 motor, now going .032 over. Already did 10 and 20 over. I run Branch-Okeefe heads, and a Crane Hi Roller 304-2 cam. Compression is estimated at 10.5:1 with 78cc heads. Dyna 2000i ignition, and Rhienhart pipes. Mikuni 45. 110hp 117torque, dyno by John Golden, 'The Dyno Guy'
"I have had lots of blow-l by on my stroker motor (4.625 stroke) and I have found several probems with the motor that I am fixing now; needs new crank pin, rods, and a bore out. The cylinders were badly scored, which I imagine helped contribute to the blow-by. I also use a S&S reed valve breather, which seems to work fine.
My question is can I route the breather tubes off the heads and back into the oil FILLER housing. This housing has a plug in it, and I thought it would be great if the mess just wound up back where it came from. Or would adding a little pressure to the oil tank cause problems? I don't think the pressure is that great. The bike is a 1995 road king.
Any thoughts on this? I really don't want to use panty liners in my carb cover."
This is a Sputhe 104 motor, now going .032 over. Already did 10 and 20 over. I run Branch-Okeefe heads, and a Crane Hi Roller 304-2 cam. Compression is estimated at 10.5:1 with 78cc heads. Dyna 2000i ignition, and Rhienhart pipes. Mikuni 45. 110hp 117torque, dyno by John Golden, 'The Dyno Guy'
"I have had lots of blow-l by on my stroker motor (4.625 stroke) and I have found several probems with the motor that I am fixing now; needs new crank pin, rods, and a bore out. The cylinders were badly scored, which I imagine helped contribute to the blow-by. I also use a S&S reed valve breather, which seems to work fine.
My question is can I route the breather tubes off the heads and back into the oil FILLER housing. This housing has a plug in it, and I thought it would be great if the mess just wound up back where it came from. Or would adding a little pressure to the oil tank cause problems? I don't think the pressure is that great. The bike is a 1995 road king.
Any thoughts on this? I really don't want to use panty liners in my carb cover."
Seasoned HDF Member
Joined: Aug 2007
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From: NW AR
I think that would be A Bad Idea. You need a vent somewhere and the oil tank is not vented. I think you would blow the dip stick up and out, which would be interesting, but not what you want. I think a better idea would be to put a catch can somewhere, like under the seat if you can.
Seasoned HDF Member
Joined: Dec 2010
Posts: 7,736
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From: Coromandel Peninsula New Zealand
Usually a big bore tube out over the rear mudguard is the way to go, the longer the tube, the less mess will make it to the end.....used to fit a catch can on old Brit bikes back in the day as some of them can pump oily crap a long way when you give them some throttle.
Seasoned HDF Member
Joined: Nov 2009
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From: Farmington ,MS
The tank is vented to the cases, but it would no longer be if you ran the vent to the tank...you need a catch can...
here ya go:http://www.ebay.com/sch/sis.html?_nk...9#ht_693wt_719
Elite HDF Member
Joined: Oct 2005
Posts: 3,872
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From: Canton, Michigan
Unless you're running a different setup, the oil 'tank' is an 'oil pan'. The MoCo changed to the pan design in 1993 on the E-Glides, where the oil pan is under the transmission case. I'd have to look at the diagram to see if the pan is vented, but I don't think it is vented independent of the oil system. I believe it gets its venting via the heads. Soooo....
If the issue is too much oil puking out the heads via the venting holes, I would go with the catch can. Which is probably what I'll be installing on my EVO, as the heads are venting a bit more oil mist than the carb can digest.
If the issue is too much oil puking out the heads via the venting holes, I would go with the catch can. Which is probably what I'll be installing on my EVO, as the heads are venting a bit more oil mist than the carb can digest.
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Cruiser
Joined: Jun 2012
Posts: 127
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From: So. California
Yeah, the oil tank/pan is under the transmission. I know that there is a vent tube from the motor case to the oil pan, as shown in the service manual. The motor was venting normally for years, then became progressively worse. I ran a breather hose all the way to the center of the rear fender, extending about 1/2 inch, so all the blow-by would get blown away, so I thought. I didn't take the back pressure of the moving bike into account, and still ended up with a mess, and when I parked, the rear fender dripped oil. Any way, when I heard it knocking, I tore it down, and found a bad rod/crank pin. So...I got it in for new rods, pin, bearings, bore out, and freshen up heads. So it will be pretty much all new when I am done. Cam and lifters are good, so they will remain. I am looking at about 5~6 weeks before I get it back together. Bennett Performance doing the crank, and bore job, Branch doing the heads, Pistons coming from Axtel on order. Nothing just off the shelf, except gaskets. I hate waiting, and I have motor parts spread neatly, and itemized over half my garage. I will do the assembly.
I always kind of known I needed a puke can, and have had ideas for a custom one. Just wanted to throw other ideas out. Now that I have the time, maybe I will make one.
Thanks for the comments guys. I will post again when I have it broke in, and have a few miles on it. I live in So. Cal, so it is always riding weather.
Be safe
Steve
I always kind of known I needed a puke can, and have had ideas for a custom one. Just wanted to throw other ideas out. Now that I have the time, maybe I will make one.
Thanks for the comments guys. I will post again when I have it broke in, and have a few miles on it. I live in So. Cal, so it is always riding weather.
Be safe
Steve
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