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Jimidan
Posted on Friday, September 21, 2007 - 09:22 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

My question is what is happening to cause this to occur in the first place. It is pretty common for many Buells to blow the cap off of the oil tank (or bladder...ewe!, as some refer to it). This aways makes a mess and is very dangerous when it gets on the tire. It is common enough that there are aftermarket fixes sold by American Sport Bike to prevent them from happening, including screw on oil cap kits.

Let's eliminate the obvious reason at the onset...when the oil tank is overfilled before the engine is started (after sitting for a while) and oil that seeped back into the sump is not taken into account in the total volume. That one is easy.

I am talking about when the oil volume is spot on (between the marks on the stick when hot and just turned off) and it still builds up enough pressure to blow the top off, spewing oil in the process. What are the physics at play here? Why does it occur with the tanks on the S1, X1, S3, and M2 and NOT the S2?
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Natexlh1000
Posted on Friday, September 21, 2007 - 09:47 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Simple: there's something wrong with the crankcase breather.
The pressure from the blow-by has to go somewhere.

Those aftermarket solutions are band-aids.
Mine has never ever built up any pressure at all in the oil tank.
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Lake_bueller
Posted on Friday, September 21, 2007 - 09:51 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

I've only had the problem twice. Once when I overfilled the tank. Second was when I tried something "different" with the crackcase breather (i.e. not letting to breath).

BTW...the first was early in my relationship with my 1998 S3T. The second was after rebuilding my S1W.
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Hootowl
Posted on Friday, September 21, 2007 - 10:07 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Doesn't the oil pump pump the returning oil faster than the supply oil in order to ensure that the sump remains dry? I think I read that somewhere. Notice that the oil is sort of foamy/bubbling when it goes back in the tank. The pump is sucking air from the engine.
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Rocketman
Posted on Friday, September 21, 2007 - 10:19 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

I don't think there is a straightforward solution to the problem.

I have this problem occurring from time to time. Usually if I sustain 100mph for 40 or 50 miles or more down the motorway, which is pulling a steady 4000rpm, on the odd occasion it just pukes out the breather like you wouldn't believe. I have the breather running all the way to the rear mounted into a K&N filter next to the rear light. When it pukes I get covered from the bottom half of my crash helmet, all down my back, and the rear tail section of the bike is dripping in Mobil 1 too. It's a right hassle. I have to find a petrol station with high pressure jet wash to clean my bike and jacket, before I can do anything else.

Other times I can be riding it hard dicing with friends or fellow two wheeled combatants one endures during the course of a days riding, and I get puked on in similar fashion. It has only happened twice this year to be fair, but twice is not fun! My temporary fix is I have taped foam around the breather filter, and it's holding for now.

To clarify, I'm running breathed on heads though stock compression and valves but no valve guide oil seals. N9 cams with HSR42 and Forcewinder, and Wiseco forged pistons with their supplied rings as per the AAC cylinders I've ran since around 2000. Stock oil pump and umbrella breather valves and Cometic gaskets. I run Mobil 1 15/50 racing or motorsport formula which is sat in a Metmachex oil tank with screwed on billet cap. I can get 3.5 litres of oil in the tank, but it's of no use or consequence. Not even as a bit of extra space to allow less pressure in the tank when I run it at 2 litres give or take, which is near as can be two quarts. Yes I've even run it slightly less than two quarts to see if it cures the problem, but it doesn't.

So what's going on. Could be I've not got good ring seal at higher RPM. Maybe the oil pump can't return the oil fast enough from the crankcase. Maybe the breather system is just not efficient enough to allow enough pressure out of the crankcase, but how does the crankcase pressurise more than what the breathers should handle anyway?

There is one solution I am told, and it is a big part of why I have decided to go for more power over and above the very nice 100rwhp I have now, and that is to go to XB heads. So it is good that I have an infrequent puking problem as it has convinced me to seek at least 200rwhp

Rocket
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Natexlh1000
Posted on Friday, September 21, 2007 - 10:37 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Anyone try rerouting the breather from the timing plug instead of having it go all the way up the pushrod tubes?

That seems to me to be the most logical way of venting the crankcase.
My XLH had the breather come off of the generator area with a reed valve.
That didn't puke unless it was left alone for a few months.
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Djkaplan
Posted on Friday, September 21, 2007 - 12:11 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Oil must be draining back down from the oil bag into the scavenging pump. When the engine is started, the pressure side of the oil pump can only pump a certain metered amount, but the scavenging side has a surplus in the supposedly 'dry' sump and sends it all pretty quickly to the oil bag. You can see the oil level in the bag get higher if you start the bike while looking inside.

The only place the volume of air has to go is through the bag vent routed to the cam case. I'm assuming excess pressure here doesn't have a free and clear path to the vents in the heads. It has to somehow make it though the lifter galley and through the pushrod covers into the rocker boxes. The whole time this stuff is trying to vent, you have return oil coming back through - it must be pretty crowded in the pushrod tubes (I suspect Buell engineers changed the small chromed tubes to the larger single plastic cover for this very reason). Anyway, the pressure eventually equalizes in the oil bag. I think another problem is the oil gets aerated by the scavenging pump and, hence, creates a volume deficit in the bag.

Does that make any sense?
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Blake
Posted on Friday, September 21, 2007 - 01:26 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Ever try removing the oil filler cap on your automobile while the engine is running? There is pressure there too. Enough pressure to pop the bung on the oil filler cap on a tuber is not unheard of for sure. But how much pressure is that requiring I wonder? Maybe not very much for an oily old rubber bung?

Buell released a new oil pump and scavenging configuration in 1998 that helps reduce the wet sumping that occurs at higher prolonged engine speeds. The retrofit requires the new pump and a minor modification to the oiling circuit inside the cam/gear case.

(Message edited by Blake on September 21, 2007)
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Rocketman
Posted on Friday, September 21, 2007 - 02:14 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

I believe when I got the new cases the supplied oil pump that came with them was the upgrade variety.

The Ford Pinto 4 cylinder engines could always be assumed good if when removing the filler cap you placed the palm of your hand over it and your palm got sucked on. If the motor were suspect it would always breathe, thus blow and not suck. Go figure!

Rocket
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Mcgiver
Posted on Saturday, September 22, 2007 - 11:12 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Ever wonder why Sportsters dont blow their oil caps? Their oil tanks have a vent on the top of them (at least my wife's '98 does), and my '98 S3 does not. Brian
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Mr_grumpy
Posted on Sunday, September 23, 2007 - 05:44 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

I got a banjo kit from Al at American Sport Bike then ran the pipes thru a T down to a small glass jar with 2 fittings in the lid, one in & one out, the out pipe then to the back of the tail section. That way the jar acts like a separator when the motor pukes & the spooge stays mostly in the jar; you just empty it now & again & it works fine.
(doesn't stop you crashing though)

ps, If your bladder is pressurising, consider asking your partner to stop jumping up and down on it.

(Message edited by Mr_grumpy on September 23, 2007)
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M1combat
Posted on Sunday, September 23, 2007 - 02:12 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

I agree with the catch can method...
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Rocketman
Posted on Sunday, September 23, 2007 - 08:52 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

I don't have a suitable place for such a contraption, but I am considering such providing I can find one small enough and stylish enough. Time's running out though. Those XB heads are looming!

Rocket
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Blake
Posted on Tuesday, September 25, 2007 - 05:57 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Ever wonder why Sportsters dont blow their oil caps? Their oil tanks have a vent on the top of them (at least my wife's '98 does), and my '98 S3 does not. Brian

Dude, you may have just hit on something. Bigtime.
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Rick_a
Posted on Wednesday, September 26, 2007 - 08:13 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

The oil tank is vented to the gearcase which vents to the heads...so technically if the breather system is operating effectively and the oil level is correct there should be no problem.

That said, I added an additional vent to my gear case to the area behind the oil filter mount. It's routed to an XR750 breather baffle. It works quite well. There is still some puke at sustained high RPM's, but nothing like before.

I've since purchased a Zipper's Pro Flow oil pump, but my bottom end needs to be rebuilt before I'll know how well that works.
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Natexlh1000
Posted on Wednesday, September 26, 2007 - 08:48 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

What does the baffle look like?
Is it to condense out the spatter?
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Rick_a
Posted on Wednesday, September 26, 2007 - 10:41 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Yes. It's a big aluminum baffle consisting of offset plates...kinda like the lower half of an XB breather...only much bigger.
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Rocketman
Posted on Thursday, September 27, 2007 - 07:13 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Rick, please tell how the Zippers works wrt puke problems, as and when you get to use it.

Rocket
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Road_thing
Posted on Thursday, September 27, 2007 - 10:41 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Rocket:

I've got a Zipper's scraper and oil pump in my S1, it runs very dry, hardly any oil mist at all out the breathers.

Of course, I don't run it 140 down the motorways very often, either...



rt
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Rick_a
Posted on Thursday, September 27, 2007 - 02:57 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Rocket, that'll be no time soon...probably next summer.
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Rocketman
Posted on Thursday, September 27, 2007 - 06:37 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

R-t, hardly any oil was not the answer I was hoping for, lol.

Thanks Rick. Next year then!

XB heads must be the cure.

Rocket
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Jimidan
Posted on Thursday, September 27, 2007 - 06:39 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Simple: there's something wrong with the crankcase breather.
The pressure from the blow-by has to go somewhere.


The bike in question in an X1 that has XB heads/rockerboxes/covers, and the PCV is routed to a catch can that is vented to the air. It does't produce much puke out of the heads at all. That seems like it would be a different issue though since the oil bladder is fed by the return line from the oil pump (on this one a 98 style).

It also has new rings/cylinders so the shouldn't be a lot of pressure for blow-by either, but we will be doing a compression/leakdown test soon to determine exactly how effective the break-in was. It burns very little oil which is changed often as this is a track bike. It is running at pretty much WFO most of the time.

}Doesn't the oil pump pump the returning oil faster than the supply oil in order to ensure that the sump remains dry? I think I read that somewhere. Notice that the oil is sort of foamy/bubbling when it goes back in the tank. The pump is sucking air from the engine.

I do not believe that the scavenging pump returns the oil faster than the pressure side...it should be pretty close to the same. I do know that the scavenging action of the pump picks up air in the process, as is evidenced when I pull off the return hose after changing the oil and let it run a minute or so to get the dirty oil out of the system...it is always coming out in fits and starts. But the volume isn't all that high.

}Anyone try rerouting the breather from the timing plug instead of having it go all the way up the pushrod tubes?

That seems to me to be the most logical way of venting the crankcase.
My XLH had the breather come off of the generator area with a reed valve.
That didn't puke unless it was left alone for a few months.


I know one guy who added a vent out of the timing plug and he said he liked it, although after seeing how much oil comes out of that hole when it has been open to shine a timing light in there, I think that would be one of the worst places to vent out of. Oil is literally blown out of there more than 6 feet away when the engine is idling, and that is with an engine that has a flywheel scraper!

I have run a vent out of one of my engines from the fake generator part of the cam cover, and it didn't produce a lot of puke out of it either, but I have that plugged since the XB rocker covers do such a great job, it is not needed...but that was on an S2.

}Ever wonder why Sportsters dont blow their oil caps? Their oil tanks have a vent on the top of them (at least my wife's '98 does), and my '98 S3 does not. Brian

The S2 has its vent out of the top corner of the oil tank too, as does the American Sport Bike aluminum tank for my S1.

The X1 track bike in question has a custom tank that was made by Rich Cronwrath, Innovative Racing, as this bike was one that was raced by Michael Barnes. It has the vent and return lines in the tank above the normal oil level, with 1/2" aluminum tubing inside going from the bungs where the hoses attach up to the airspace in the tank. I think this is an imperfect design for the vent so we are going to modify it with a bung to allow the vent to come right out of the top of the tank.

However, we have changed out this tank with a plastic stock X1 tank when we had to get the aluminum one welded, and the stock tank blew the rubber bung off.

}That said, I added an additional vent to my gear case to the area behind the oil filter mount. It's routed to an XR750 breather baffle. It works quite well. There is still some puke at sustained high RPM's, but nothing like before.

I've since purchased a Zipper's Pro Flow oil pump, but my bottom end needs to be rebuilt before I'll know how well that works.


I had a vent to the top of the cam cover too on one of my 88" engines too, like I said above. We may try to put one on the X1 racebike too if all else fails, it has to relive some of the case pressure.

I have a couple of the ProFlo pumps and they are great...18 lbs. of oil pressure at 3000 RPMs. I have squirters in these engines and they take some oil pressure to make them work. It works great in keeping the engines cool even with the Axtell cylinders, and scavenges like a MoFo.

The downside to the ProFlo pumps is that they cost $550 or at least they used to...they may be more now. Buell's new design (thanks to the XBRR) is the way to go with this type of engine if they only could be retrofitted...which they can't.}
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Chasespeed
Posted on Friday, September 28, 2007 - 03:04 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

So I take it, X1's are freaks, with the Tank Vents?

Mine has it, and it has NEVER blown the cap...

Never puked either... only place mist/puke collects is the catch can...

Chase
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Jimidan
Posted on Friday, September 28, 2007 - 11:23 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

I don't think that the X1 has a hold on the market for tubers blowing the rubber bungs out of its bladder, as I have heard owners of S3's, M2's, S1's have the same problem. Those bikes all have a very similar looking designed oil bladder. The S2 has a very different designed bladder, with a large expansion area above the oil level and with it's vent in the upper corner.

The X1 race bike in question has a custom tank but I question the design of the tank's vent location, and we are going to change it. It has a screw top so it cannot pop it out, but is has the sides bulged from the pressure, and actually started forcing oil out of a crack in the aluminum around one of the welds. I reiterate though, that even with a stock plastic bladder, it still pressurizes the tank and will pop the bung.
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Johnc
Posted on Friday, September 28, 2007 - 04:21 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

I don't know about Buell engines specifically but from my experience building dry sump 360 and 410 ci sprint car engines, the return side of the pump should always be about 2 times the capacity of the pressure side to ensure wet sumping does not occur. This will result in a pressurized oil tank that needs to be vented.
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Rocketman
Posted on Friday, September 28, 2007 - 04:57 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Jimi, your post is basically saying that running the XB complete head assembly offers very little puke out the breather system. This is despite running your bike WFO often. Great news. Glad to hear it.

I'm pretty much agreed with everything your post says. I can't comment on the oil pump return as I've not got to the Zippers stage yet, but I too have difficulty in seeing how returning the oil faster is going to prevent the breather puke problem. For me I see the problem as too much oil getting up into the umbrella cavity. This has two problems if this is the case. The drain hole can't remove the excess oil fast enough, and the umbrella valve is to close to the drain thus acts as a drain itself when the oil builds up significantly in the umbrella vale area.

I'm still after all these years not entirely sure how the check valve and its opening pressure in the oil filter housing has a relationship to the oil pressure and quantity delivered into the rocker housing, so is this a cause of too much oil delivered to the rocker area for the breather system to be involved with?

Rocket
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