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#331937 - 09/06/10 7:26 am Cracked scavenge tube and wet sumping...  
Joined: Jun 2007
Posts: 95
BSA-KC Offline
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BSA-KC  Offline
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Joined: Jun 2007
Posts: 95
Dallas, TX
My 1968 A-65 Lightning motor suddenly started to wet sump. Not the “It only sat for two weeks and all the oil in the tank was gone” kind. Mine happened while riding and gave everything behind the breather a nice dripping coat of oil, including the rear tire. Some friends helped me get it home and I drained what was left in the sump, re-filled the tank and took it around the block and then had a look in the oil tank and sure enough it went from full to half full. The strange thing was that I could see oil WAS returning to the tank, just not fast enough. I figured this would be the perfect excuse to install the cast iron oil pump I had recently rebuilt. The pump was re-assembled with great care and is tight but turns. I removed all the oil lines for inspection and to be replaced. No problems there. Once I got into the inner timing case I expected to find a loose oil pump stud or something but EVERYTHING checked out fine. After checking the cases for any obstruction, I could not find anything that would have caused the wet sumping. I installed the new pump, new lines, made sure nothing was restricted, plumbed the top end feed after the spin on oil filter, thoroughly cleaned out the oil tank, got it all back together and figured everything would be good to go. I even replaced the stainless OPRV I obtained from Brit-cycle with an SRM one that I had for another project just to be sure. On the test ride around the block… The same thing happened, only this time MUCH faster. Then I tried everything I could think of… Re-plum the oil lines, change the filter again, check the scavenge pipe ball AGAIN etc…After spending hours on the forum going over all the advice on Redmans oil issues from about a year ago I was getting ready to plug a vacuum gauge on to the scavenge pipe when I grabbed an oil can and pushed the tip up to the scavenge pipe and gave it a couple of squirts just to see what would happen and each squirt immediately came back down into my hand. I grabbed a flashlight and a mirror and tried it again and the oil was coming right back out the top of the scavenge tube. My only guess is it was poorly brazed and developed a crack??? I guess this could cause it to wet sump like it did because as I said, oil was returning to the tank, just not as fast as it should and obviously not faster than it was being fed to the motor. I would think that it would not make that much of a difference, if the crack in the tube was submerged in oil wouldn’t it still be sucking it in and sending it back to the tank just the same? I’m hoping I have gotten to the bottom of this because after double and triple checking everything I feared an internal crack in the cases that couldn’t be seen might be the problem.

So, could this be a cause of wet sumping or at least decreased return flow leading to wet sumping?
Has anyone ever successfully replaced the scavenge tube with the motor in the frame?
Hope So…
Thanks for any advice in advance.
Casey


Thanks y'all.

1968 BSA Lightning Hard Tail
1972 BSA Thunderbolt

www.caseykinney.com
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#332006 - 09/06/10 3:53 pm Re: Cracked scavenge tube and wet sumping... [Re: BSA-KC]  
Joined: Jan 2004
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DMadigan Offline
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ca, us
If the pickup tube was cracked you would have more oil than normal in the sump. High enough to reach the flywheel and it will throw it around the case so more than static level will be in there but it should still come to an equilibrium.
You could put a large catch pan under the motor with the sump plate off, idle the motor and check there is suction on the end of the pickup. Just do not stick your finger into the crank. Or else push a piece of clear plastic hose over the pickup and put the other end in a jar with oil, see if the pump pulls the oil up the tube.
The oil pump should not be tight. It has clearances on the shafts and gear faces and should turn freely.
Try replacing the top end oil line with a clear one and see how much oil is going that way. Could one of the rocker shaft end bolts be missing?

#332117 - 09/06/10 11:23 pm Re: Cracked scavenge tube and wet sumping... [Re: BSA-KC]  
Joined: Oct 2008
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DavidP Offline
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Gnashville
Originally Posted By: BSA-KC

Has anyone ever successfully replaced the scavenge tube with the motor in the frame?
Hope So…
Thanks for any advice in advance.
Casey


I've done it, no fun, lying on your back with a torch in one hand and some vicegrips you get the old one out.
The real fun is installing the new one and getting it to line up with the hole in the sump screen.


Stepping on others doesn't make you stand tall.

71 A65L "Zelda"
92 BMW K100rs "Gustav"
#332142 - 09/07/10 2:01 am Re: Cracked scavenge tube and wet sumping... [Re: BSA-KC]  
Joined: Aug 2001
Posts: 3,871
Mr Mike Offline
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Mr Mike  Offline
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Posts: 3,871
Cape Carteret, NC
Here's a couple of suggestions: (1) drop the sump plate and put a rubber hose on the pickup. Blow on it to see if you can here air hissing out anywhere. If there are no leaks it will be hard to blow thru the pump gears back to the tank. If there is leak yo may be able to find it. (2) if you don't find a leak, do as D madigan suggests and put a big catch pan under the sump. Hook up one of those squirt oil containers that gear oil comes in. Fill the container, and hook it up to the hose on the pickup tube and find a way to hold it at about the same level as the bottom of the pickup tube. Gear pumps don't generate a lot of suction so you don't want to have to lift the oil four or five extra inches. Crank your motor and see if it sucks the oil from your container. Have extra oil ready to add if the level drops in the tank. If you use clean containers the oil can all be reused. (3) I have replaced pickup tubes with the engine in the bike. Have to lay it over on its side and use a torch and vicegrips. It is pressed in not brazed.

In my opinion the BSA dry sump design has a less than desireable feature. Inlets to the gear pumps should be gravity or pressure fed. The pressure side is gravity fed but the scavenge side requires the gears to lift the oil...... something they are not well suited to do. But this system is on lots of dry sump BSA bikes and dry sumping is a common problem. In fact the entire lubrication system on BSA's has always been a weak point intheir designs.

Good luck,
Mr Mike

#332182 - 09/07/10 7:57 am Re: Cracked scavenge tube and wet sumping... [Re: BSA-KC]  
Joined: Jun 2007
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BSA-KC Offline
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Dallas, TX
Hi Dmadigan, DavidP and Mr Mike
Thank you all for your reply's. I have confirmed that there is a crack in the top of the scavenge pipe.
When I had the mirror and flashlight under there and squirted oil into the pickup tube the oil just poured back out the top of the tube right where it is brazed to the horizontal part of the scavenge pipe coming out of the case, above the ball. I stuck the rubber nozzle of my air hose up to the pipe as well and air came shooting out the top so I am sure there is a crack up there I just cant figure how it would really matter or cause such a reduction in return flow as to cause it to wet sump so fast. As I said before I am getting return flow to the tank, but normally just a drizzle down the return pipe in the tank, sometimes with bubbles and sometimes without. It seems to keep up and slowly start to refill the tank at idle, but as soon as I take it around the block again the same thing happens.
I hooked up an empty gear oil bottle with 20/50 and a 3/8 hose connected to the pickup and just as I figured, as soon as I turned it upside down to let the oil flow to the pickup tube it started pouring out the crack and back down into the aluminum baking pan I had folded up around the lower end. I started the bike and ran it for less than one min. as there was almost no return. The feed side was certainly working though, what a mess. The level of oil in the gear bottle fell very little and I can only assume that the crack might have been sucking air/oil mist and not letting the tube do its job of just picking up oil. The only thing is, If the sump plate were on, the cases would have and do fill to a level above the crack so at this point, there would be oil at the bottom of the pickup tube and above the crack so then it would only be sucking oil …….. OK, so I just realized that basically raises the suction point in the pickup tube from where the ball sits (where it was designed to be) up to just underneath the spinning crank…
I just seems that if its filled with oil, the pump should still be able to remove it to at least the level of the crack right?
Oh, and regarding the pump, when I said “tight but turns” I meant the tolerances were tight and I can still turn it with my thumb. I can actually feel the gears engaging one another so I’m confident the pump is not the problem. I used a “britgasket” and took great care when mounting it to the cases.
As much as I hope this crack in the pickup tube is the cause of my wet sumping, I just don’t see how it could allow the cases to fill with oil. There has got to be something else I'm missing but the tube needs to be replaced regardless.
A few of the normal suppliers show the tube in their price lists so I imagine it shouldn’t be too hard to get a hold of one. I’ve also got a set of damaged cases I could remove it from and the part number is the same in the ’68 and ’71 books.
Lay the bike on it’s side huh?… Man… My girlfriend’s gonna be real mad when she sees what I’ve done with the couch cushions and all our pillows. Probably even madder than last time...
Thanks again guys, I'll let you know how it goes and I welcome any further advice,
Casey


Thanks y'all.

1968 BSA Lightning Hard Tail
1972 BSA Thunderbolt

www.caseykinney.com
#332217 - 09/07/10 12:45 pm Re: Cracked scavenge tube and wet sumping... [Re: ]  
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Mr Mike Offline
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Cape Carteret, NC
You are on track. AS i mentioned in my post, the scavenge side is marginal to start with as it must lift the ball and does not have a steady stream of solid oil to make good suction so if anything is wrong the system fails. I used a lot of gear pumps in intustry and we ALWAYS either immersed the inlet in the fluid being pumped or pressure fed the inlet with a relif bypass. 99% of all engines have a wet sump where all the oil sits below the engine and never causes a problem unless you over fill it. The dry sump like on our BSA's allows the designer to have clearance under the engine....something needed on a motorcycle esopecially those that go off road.

Practice taking one of those pickup tubes out of a spare case. You can do it. Did you use your girlfriends baking pan too?

Mr Mike

#332381 - 09/08/10 8:20 am Re: Cracked scavenge tube and wet sumping... [Re: BSA-KC]  
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BSA-KC Offline
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Dallas, TX
Oh no Mr Mike, I may be dumb but I’m not crazy.
Actually a lot of the “$1.00” stores around here sell those REAL heavy duty aluminum foil baking pans in stacks of three for a buck. They are big enough to fit a turkey and therefore make the perfect drip pan for the entire lower end. They are also perfect for opening up either side to drain the oil because they’re about 3-4” deep and you can kind of fold one of the corners into a pour spout for emptying into an oil container for later recycling.
Anyway, I got the scavenge tube out of my spare set of cases and it didn’t take much effort but it did take a good amount of heat. I had the vice grips on hand just in case but I was a little weary of damaging it while trying to remove it(everything I touch with vice grips turns to scrap, maybe I just need more practice) and a 1/4in. drive – 11mm deep well socket fit the outer diameter of the tube with almost no play at all so I used that on the end of a hand held socket driver to wiggle it back and fourth and eventually right out with little effort. I just kept one hand on the torch and one hand on the socket driver and as soon as I got it to start twisting a bit I put the torch down and slowly wiggled it on out. There’s a lot of meat around that thing so I tried to spread the heat around as much… and as little as possible because when I get to the other one I’m going to have a lot more than just a stripped down set of cases to deal with. Looks like the OPRV will come out and the oil manifold with the new quatro rings will come off. I’m a little concerned about the O ring on the gearbox drain plug but I figure with the bike on its side I could just take the drain plug out and put it back when I’m done.
What about the inner timing cover though??? And now that I think about it, the oil pump too??? I used grease to shine the pump gasket and thin smear of hylomar on the cover gasket. I’ll have to look up how much heat hylomar can take.
That thing was in there pretty good so I now understand what DavidP is talking about when he said
“The real fun is installing the new one and getting it to line up with the hole in the sump screen.” I better come up with some new swear words before I get started not to mention some type of crazy shaped drift that won’t cause similar damage upon re-installation.
I had first imagined laying it on the drive side but it looks like laying it on the timing side will make it easier to re-install.
Hey DavidP, did you remove your inner timing cover when you did this?
I guess I could also take a couple of those aluminum baking trays and at least try to shield some of the surroundings from the direct heat of the flame…
Again, thanks guys for your suggestions and I welcome further advice.
Casey


Thanks y'all.

1968 BSA Lightning Hard Tail
1972 BSA Thunderbolt

www.caseykinney.com
#332383 - 09/08/10 8:44 am Re: Cracked scavenge tube and wet sumping... [Re: BSA-KC]  
Joined: Jun 2007
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BSA-KC Offline
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BSA-KC  Offline
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Joined: Jun 2007
Posts: 95
Dallas, TX
Hey overandout,
Thanks for the words of encouragement. Yep I’d say around my block is around ¼ mile, give or take and on a couple of test runs that would pump over a quart out of the tank. I consider myself lucky because when this first happened my destination was very close to home but at the same time, when I arrived my rear tire looked like it had been dipped in a big vat of oil. It could have been a lot worse for me and my bike. I hope your friend had the same luck that I had that day.
Casey


Thanks y'all.

1968 BSA Lightning Hard Tail
1972 BSA Thunderbolt

www.caseykinney.com
#332500 - 09/08/10 10:05 pm Re: Cracked scavenge tube and wet sumping... [Re: BSA-KC]  
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DavidP Offline
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DavidP  Offline

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Gnashville
"Hey DavidP, did you remove your inner timing cover when you did this?"

No, KC I did this after the first oil change when I noticed the old pipe had torn the screen and didn't line up with the hole in the new screen.
I got it out with the bike upright. After that struggle, I leaned the bike over to install the new one.

BTW: The pipe still doesn't quite align with the hole in the screen. I wonder if it ever did.


Stepping on others doesn't make you stand tall.

71 A65L "Zelda"
92 BMW K100rs "Gustav"
#332537 - 09/09/10 12:40 am Re: Cracked scavenge tube and wet sumping... [Re: BSA-KC]  
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Mr Mike Offline
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Mr Mike  Offline
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Cape Carteret, NC
KC,
It has been a while since I put one of those pickup tubes in and the details I have forgotten, but i seen to remember that I fashioned something to tap it back in and it when without a lot of heat. The key is getting the right agnle to tap on it twisting it so the hole line up with the hole inthe screen. It seemed to go easier than I expected....something that is rare for me.
Hey one time I was working on my bike engine in the dead of winter up in Massachusetts. It was bitter cold and I had no workshop. My wife was going shopping with some friends so I took apart my motor on the kitchen table and had it back together and cleaned up before she got back. I was also babysitting my year old son in the process.

Something is not right with us guys that work on these old bikes.

Mr Mike

#332573 - 09/09/10 8:13 am Re: Cracked scavenge tube and wet sumping... [Re: BSA-KC]  
Joined: Jun 2007
Posts: 95
BSA-KC Offline
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BSA-KC  Offline
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Joined: Jun 2007
Posts: 95
Dallas, TX
Mr Mike,
Haaaaaa! That’s awesome. I needed that! My neighbors are probably dialing up the looney bin right now because I just topped off a marathon of obsenities (while removing the damaged pickup tube) with histerical laughter.
I got the scavenge tube in question out of the cases and it was not as easy as the other one. The top of the tube that the ball sits in had not been compleetly brazed all the way around to seal it shut so it looked like if you took a can opener to a can and only went about 1/3 of the way around and then pried the lid open a little bit so it was leaking at that point although I’m not sure if “leak” is the right word for what was going on down there. That pipe was really stuck in there though and I will surely have to come up with something to assist in drifting the new one back in. I still have the origional sump plate that came on the motor and it is the kind that has the big mesh screen soldered to the inside of the cover so if I can’t get this other one to go all the way back in I could use that sump plate as you can kind of move the mesh screen around a bit to make it fit. I’m going to try my best to get it in there though because I brazed a ½-20 nut to the sump plate I’ve had on there and have a magnetic drain plug that I don’t want to lose the use of.
DavidP,
I too got it out with the bike upright, and now I know why you went to the trouble of leaning the bike over to install the new one. I thought I had been doing a good job of keeping the floor of my new shop clean… Now that I’ve been down there for a while, it looks like I need to try a little harder.
Overandout,
Good, yer buddy got lucky just like me and it makes you feel even luckier to have buddies that will come help you haul your “bucket O’ bolts” home doesen’t it.(at least that’s what they said to me but hey, they ride “harlies”)

I’ll let y’all know what happens next and thanks again for all the help and advice.
Casey


Thanks y'all.

1968 BSA Lightning Hard Tail
1972 BSA Thunderbolt

www.caseykinney.com
#332880 - 09/11/10 1:41 am Re: Cracked scavenge tube and wet sumping... [Re: BSA-KC]  
Joined: Jun 2007
Posts: 95
BSA-KC Offline
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BSA-KC  Offline
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Joined: Jun 2007
Posts: 95
Dallas, TX
SUCCESS !!!
I Last night I installed the scavenge tube donated by my set of damaged cases. Upon doing so I was met with good news and bad news. The good news was the tube went in without having to heat the cases again. The bad news was the tube went in without having to heat the cases….. When I test fitted it with the help of that 11mm deep well socket I was able to wiggle it almost all the way in. It wasn’t real easy but it certainly wasn’t too hard. Then I really got under there to inspect the hole I found that there was a lip in there to stop it right where it needed to be and I wasn’t quite there on the test fit. I took a rat tail file to a cheap harbor freight ½” brass punch and made the end concave at the same angle as the tube that goes into the cases so I could hit it straight without it slipping to the side and damaging the gasket surface down there. Then I cleaned the hole with some mineral spirits and sprayed some locktite activator on a Q-tip and swabbed the hole. After reinserting the scavenge tube, tapping it all the way home and checking it’s position with a new sump screen, I applied some of that green capillary action loctite with a new and clean tiny artists brush and buttoned the sump back up. Today when I got home from work it was time for the test ride. I have found that an easy way to get some oil down there to prime the return after re-fitting a clean and dry sump plate is to just sit on the bike and lean it a little to the left for a couple seconds. This lets some of the oil that's sitting in the timing case spill over into the sump. I started it up and was a bit disappointed at first because I only saw the same drizzle as before when all of the sudden oil started to shoot out of the return line like it never had before. So I hopped on and took it around the block, pulled back into the driveway to check it with a flashlight and THERE WAS STILL OIL IN THE TANK. So I hopped on and took it around 2 blocks and checked again and THERE WAS STILL OIL IN THE TANK!!! So I took it out for a mile or so and checked again and THERE WAS STILL OIL IN THE TANK!!!
I just got home from a nice evening ride and wanted to sit down and let you guys know how things turned out and thank you all for your help and support. I’ll post some picks of the old scavenge tube as soon as I get them up on photobucket so you all can see what caused all this trouble to begin with. I sure do appreciate the help you guys gave me and I hope that sometime soon I can return the favor.
Until then, thanks again,
Casey


Thanks y'all.

1968 BSA Lightning Hard Tail
1972 BSA Thunderbolt

www.caseykinney.com
#332915 - 09/11/10 11:59 am Re: Cracked scavenge tube and wet sumping... [Re: BSA-KC]  
Joined: Aug 2001
Posts: 3,871
Mr Mike Offline
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Mr Mike  Offline
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Cape Carteret, NC
Good for you! Enjoyed your sense of humor completing a task that is not so easy while never being sure it would cure your problem. In my book the BSA lubrication system is somewhat marginal and one must have everything in good shape to have a sound motor. If I ever have to do my motor over again, I will have the best oil pump I can find,a working and go thru the lube system in every detail.

Mr Mike

#333199 - 09/12/10 10:50 pm Re: Cracked scavenge tube and wet sumping... [Re: BSA-KC]  
Joined: Jun 2007
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BSA-KC Offline
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BSA-KC  Offline
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Posts: 95
Dallas, TX
Thanks a bunch Mike for your help.
I’ve realized that a good sense of humor when it comes to this old bike is just as important as any tool in the shop. You are right too, I wasn’t 100% sure replacing the scavenge tube would solve the problem but it was the only thing I could find that could have been the problem short of an internal crack in the cases that could not be seen. I still don’t understand exactly how or why it would still not have been able to remove the oil from the crank case at least to the level of the top of the tube but I guess all that matters is that the problem is fixed.
This is the tube that came out of my bike. I had to use a clamp to help pull it out as I twisted and it came in contact with the top of the tube in the process. I suspect that the top was open a bit more than what can be seen in the pic. It is clear though that it was poorly brazed from the factory. Only about ¼ of the top had been sealed when it was brazed.

This is the one from the spare set of cases and it's what the other one should have looked like.


Now I’m ready to return to the 72’ Thunderbolt that has been put on hold so many times. Right before the 68’ developed it’s wet sumping problem, I had just put the cylinders on and was getting ready to bolt on the cylinder head when I got side tracked. Time to get back at it.
Thanks again for all your help,
Casey


Thanks y'all.

1968 BSA Lightning Hard Tail
1972 BSA Thunderbolt

www.caseykinney.com
#349018 - 12/20/10 10:09 am Re: Cracked scavenge tube and wet sumping... [Re: BSA-KC]  
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Mark Parker Offline
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Bega NSW Australia
Hey KC, it needs suction in the pickup tube to lift the ball, that crack in the brazing isn't big enough to take all the oil out of the sump, but it would decrease the suction in the pipe and maybe not lift the ball enough to open the pipe. Wonder if thats whats wrong with Redmans?


mark
#349361 - 12/22/10 4:33 am Re: Cracked scavenge tube and wet sumping... [Re: BSA-KC]  
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BSA-KC Offline
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BSA-KC  Offline
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Dallas, TX
Hi Mark,
Good point. The more I think about that the more I think that had something to do with it.
You know, I just re-read Redman's thread from 10-19-09 (over a year ago, is he still having the same problem? Maybe I'm not using the Search function correctly?)
http://www.britbike.com/forums/ubbthread...true#Post280132
I think what made the problem so elusive was the fact that I was still getting oil return to the tank, just like Redman said he was in his post but it's difficult, at least for me to judge the volume of the stream coming back into the tank just by looking. I remember reading Redman's thread when my problem first began but at the time I had not started to investigate exactly what was going on. I just knew it had wet-sumped while riding and soaked everything behind the motor. After re-reading his thread it looks like I was experiencing the exact same symptoms Just like Redman, at idle everything appeared fine and I even watched the oil level in the tank rise back up to its normal level while idling in the driveway right before the first test run after installing the cast iron pump(I purposely put a little over half a quart in the sump before the first startup with the rebuilt pump because I wanted to see that the cast iron pump was working). One lap around my block and back into the driveway to check the level in the tank and it was almost empty again, HOWEVER, oil was still flowing out the return line back into the tank AND now that I was back in the driveway with the engine at idle I again watched as the oil tank slowly started to fill the tank back up. As I watched it start to slowly fill back up I remember very distinctly that I gave the throttle a couple short twists with the expectation that I would briefly see a small increase in the return flow but instead what I saw was the flow drop to almost nothing for about 3 seconds directly after the motor settled back to it’s idle after the short rev’s. At this point I shut it down for fear of overheating from idling in the driveway for too long but I should have paid more attention to what I had just seen. At that moment I was very disappointed though and all sorts of things were going through my head as to what could be wrong. After all I had just installed a very carefully rebuilt (not to mention expensive) cast iron pump as well as an SRM OPRV and replaced all the oil lines, gaskets and filter after having checked all pathways in the cases for blockage etc… this was supposed to be the test ride that ended with the satisfaction of a job well done. In my frustration I briefly traded concentration and attention to detail for swear words and buyers remorse over the few hundred dollars I had just seemingly flushed.
Going back to your comment, it seems like the crack in the top of the tube could have caused just enough of a drop in suction that at idle the return side would still have some flow back to the tank but would just barely be able to keep up and over come the feed side and that would give the appearance that the return side was working fine. Then as the throttle opened and rpm’s increased , the flow from the feed side would have increased while the suction in the return would probably still be struggling with the same reduced rate of flow it had at idle and as a result would quickly be overwhelmed.
As for the reduction in the return flow when the engine is revved a little, I don’t know… The top of the pickup tube looks to be about 3/16” directly below the rotating flywheel. Maybe as the rpm suddenly increases causing a just as sudden increase in vibration, turbulence and pressure inside the cases, the increased velocity of the flywheel could have been whipping the oil up and away from the top of the pickup tube allowing the crack to briefly suck air/oil mist causing the pump to lose prime until the rpm’s slow a bit and allow enough oil to settle for the pump to prime itself again, of course with the crack also still affecting suction.
Regardless of what was technically happening, a new pickup tube cured ALL symptoms and mine were almost identical to the ones described by Redman in the thread at the link I posted above so if anyone is in contact with him and he is still having the same issues tell him to squirt some oil up into the pickup tube for no other reason than to rule out a crack as a possible cause of his trouble. It's probably a long shot as I doubt a large number of these bikes left the factory with poorly brazed pickup tubes but I’ll bet mine wasn’t the only one.

“WHAT? Charlie’s out sick today??? This is the third time this month !!! Aww HECK! Well.. Hmmmm… Let’s see now… Hey YOU,.. yes YOU, with the BROOM. Come over here. Are you familiar with Brazing? Yes, B-R-A-Z-I.. Ya’ know what, It’s not important… You see the four boxes of little parts over there by the TORCH?

Thank you for the input and by the way, your "Overhaul" thread on the Members project board has got to be the coolest BSA thread in all of the world wide web. I look forward to future updates!

Casey


Thanks y'all.

1968 BSA Lightning Hard Tail
1972 BSA Thunderbolt

www.caseykinney.com
#349428 - 12/22/10 3:16 pm Re: Cracked scavenge tube and wet sumping... [Re: BSA-KC]  
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Posts: 3,871
Mr Mike Offline
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Mr Mike  Offline
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Joined: Aug 2001
Posts: 3,871
Cape Carteret, NC
KC,
Gear pumps are positive displacement pumps that when deadheaded can develop very high pressures and therefore we must use a pressure relief. The suction side of a gear pump, however, is its weak point. Unlike a rubber impeller pump or a diaphragm or piston pumps, a gear pump does not generate a lot of suction. In industry I used a lot of gear pumps and we always designed it so the inlet side was immersed in the fluid we were pumping or we mounted the gear pump to the bottom of the tank where gravity helped the suction side....just like the feed side of the pump where the oil is gravity fed to the inlet. It does not surprise me that a crack in a pickup tube or a sitcking non return ball can easily be the culprit in wetsumping.

Your posts have helped a lot of folks understand this.

Mr Mike

#375061 - 05/24/11 8:19 pm Re: Cracked scavenge tube and wet sumping... [Re: BSA-KC]  
Joined: Oct 2004
Posts: 1,058
Redman Offline
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Redman  Offline
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Joined: Oct 2004
Posts: 1,058
San Francisco
WOW, am I glad I came in here again!!!!! Hi guys, I was soooo pissed off at Buster after all the trials and fixes and tests with no results (regarding the wetsumping issue) that I retired him to the selfhealing area for a couple of years. I bought and rode and then sold, a Hda Superchicken 1000 twin, a Hda CBR1000RR (brand new 2008 and wow, what a rocketship), and finally a 2004 R1100S Bimmer. They have all been sold and it was time to resurrect Buster. I started with a peace offering of rebuilding the front forks completely. Then came a careful washing and complete polishing. Then, the new gas and battery. Then, after I had a thought of the one way breather valve overwhelming the return side of the pump, I took it out and test rides of increasing length were made. Longer and longer rides, stopping every mile, then 2 miles, then 5 miles, to check oil level in tank, showed everything to be normal. I was just getting to the joyful YAY part when....
Test ride up 5 miles of freeway speed produced no problem. Bike is fully warmed. Check tank...good. Up mountain for about 5 miles and pull over at the EXACT same spot at which all the other previous test rides showed glossy rear of bike and almost empty tank and.......@#$%^&*() same exact thing again. So, I've wracking my brain again trying to sort this shite out and dipped back in here to look for an OPRV flow diagram and found this thread. May not have time today but....the sump pick-up pipe is now the object of my scrutiny. Please BSA God make it be so....
I was sooo looking forward to riding Buster again...and sooooo disappointed when he did it to me again.
My theories are as follows:
No breather one way valve allowed for much slower build up of oil in CC. Perhaps the leanings of the mountain ride somehow sloshed the oil in CC around so as to create air intake to the PU tube...who knows. I'll report back in a few days when I have inspected/removed the PU pipe.
My fingers are soooo crossed.


Life is short but very wide.
#375072 - 05/24/11 9:04 pm Re: Cracked scavenge tube and wet sumping... [Re: BSA-KC]  
Joined: Oct 2004
Posts: 1,058
Redman Offline
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Redman  Offline
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Joined: Oct 2004
Posts: 1,058
San Francisco
I couldn't resist, so I went right out and drained the 2-3 qts from the CC from the last ride a few days ago. The PU pipe is not loose. The ball bearing lifts off with no pressure at all. I put a rubber tube over the end of the pick up and blew....I could get some air into it and hear some slight hissing at first but not now??? I'm getting grey hair from this....


Life is short but very wide.
#375081 - 05/24/11 10:00 pm Re: Cracked scavenge tube and wet sumping... [Re: BSA-KC]  
Joined: Oct 2004
Posts: 1,058
Redman Offline
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Redman  Offline
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Joined: Oct 2004
Posts: 1,058
San Francisco
And now...after further blowing; steady high mouth pressure, I can hear it gurgling from the crankcase/sump opening. That is not supposed to happen correct? If at all...it should be blowing out the oil in the line thru the pump and all the way back to the tank before escaping as air right? The fact that it took some steady blowing and then the sound was a gurgling, has me believing that the "leak" is not right there at the sump pick up tube. The supply and return flows of the pump are independent no? That means it is not possible that I am now blowing air up the pipe, thru the pump and out the stuck OPRV, correct?


Life is short but very wide.
#375287 - 05/25/11 9:11 pm Re: Cracked scavenge tube and wet sumping... [Re: BSA-KC]  
Joined: Oct 2004
Posts: 1,058
Redman Offline
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Redman  Offline
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San Francisco
Still tryin to get a read on this .....bump!


Life is short but very wide.
#375383 - 05/26/11 8:06 am Re: Cracked scavenge tube and wet sumping... [Re: BSA-KC]  
Joined: Jun 2007
Posts: 95
BSA-KC Offline
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BSA-KC  Offline
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Posts: 95
Dallas, TX
Redman,
I heard the same gurgling sound when I forced air into the pickup tube but I did it with compressed air. The sound really didn’t tell me anything. Try squirting oil up through the pickup tube. My tube was not loose and the ball was not stuck. The only way to find out if your pickup tube is cracked or suffers from poor brazing is to take an oil can with a flexible hose, hold the nozzle firmly up against the hole in the pickup tube and give it a couple swift squirts of oil. If oil immediately comes back down all over your hand and continues to with each squirt I would say you may have found your problem.(or at the very least part of it). After going back over the BSA board from the first post again I found two references to the EXACT same problem I had with the pickup tube but the threads lost focus and never came to any conclusion however they did confirm my believe that mine was not the only one to have left the factory with a poorly brazed sump tube. I saved the links to those posts and probably made the entire threads into PDF’s but I’m not sure where they are right now and its late where I am and have to be at work early. I’ll find them and post them ASAP.
Glad to see you’re letting Buster out of detention .
You’ll get’em fixed.
Casey


Thanks y'all.

1968 BSA Lightning Hard Tail
1972 BSA Thunderbolt

www.caseykinney.com
#375442 - 05/26/11 4:28 pm Re: Cracked scavenge tube and wet sumping... [Re: BSA-KC]  
Joined: Sep 2004
Posts: 269
EWebster Offline
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EWebster  Offline
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Joined: Sep 2004
Posts: 269
Red, did you ever do the vacuum gauge test on the pickup tube? It tells everything you need to know about the integrity of that part of the system. Hot engine, drop sump plate, rubber tubing, vacuum guage and fire her up over a dip pan..done. Too nice of a machine to not enjoy.

#375449 - 05/26/11 5:00 pm Re: Cracked scavenge tube and wet sumping... [Re: BSA-KC]  
Joined: Oct 2004
Posts: 1,058
Redman Offline
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Redman  Offline
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Posts: 1,058
San Francisco
OK gents...I'll do oil can (if I can find something like that) and then guage, if oil does not comes drooling down right away. Report back in a day or so...thanks for chiming in. I too want to be riding him again...I've got him set up pretty well ....


Life is short but very wide.
#542140 - 05/08/14 7:08 pm Re: Cracked scavenge tube and wet sumping... [Re: Redman]  
Joined: Oct 2004
Posts: 1,058
Redman Offline
BritBike Forum member
Redman  Offline
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Joined: Oct 2004
Posts: 1,058
San Francisco
OK friends...I have returned. I never did get it figured out, then moved to a place where bikes are no fun to ride, then back to the beautiful northbay where the 51st Rally has been held all this week. That did it...I'm now going to fix it or get a whole new engine.

Here's the latest. After driving over (on 4 wheels )the the camp where all the gents are, and talking to a handful about this problem...I'm back to Casey's fix. First I put on a vacuum gauge and it wouldn't budge. Guess that sump pick up ball works. Then I cobbed together a bicycle pump and hoses/fittings/etc, and removed return line hose at banjo, plugged with thumb, and pumped some air pressure in. After first seeing that my apparatus worked by pumping all the oil out of the line into the tank, gentle pressure with thumb on tube and after a moment a slight hissing from up in the crankcase.
The noise comes from deep up in the CC, NOT from near the sump pick up tube end. The pipe itself is rock solid in the case. I guess it might be solid but be leaking down the side of the pipe where it seats into the case?
Anyone want to chime in before I mangle the pipe getting it out and have to split the cases to repair it all?
Looking for light at the end of a multi year tunnel...
Kevin


Life is short but very wide.
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