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Oil Sight Glass


Rx_Mich

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A word to the wise on an older bike..... REPLACE this thing! I have a 1996 R1100RT. Due to heat cycles over the years, the plasticisers in the rubber can cause shrinkage and out it pops on its own. In BMW's wisdom, there is nothing that keep the rubber plugged window in place other than friction. There is no retainer ring locking the plug in place. I lost mine on I-75 at 80 mph and dumped 4 quarts of oil in 1 mile. Got the bike stopped along the side of the road and kept it upright even though the rear tire was drenched in oil. The only indication something was wrong is I could hear louder engine sounds through the site glass hole.

 

It could make for a really bad day when your rear tire gets drenched in synthetic oil at high speed.

 

https://www.flickr.com/photos/20370927@N03/albums/72157658499692379

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Morning Rex_Mich

 

Did you do an engine warm-up before riding this morning (I see it was around 50° in your area this morning?)

 

Running an (in place) engine warm-up is a good way to have a sight glass fall out as that hot exhaust pipe really heats the sight glass area with no air flowing over the engine.

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I saw two sight glass windows fail at one rally within an hour of one another. Like dirtrider said, it was a cold morning and they both did a warm up. 200 yards from camp they puked out.

My sight glass window began to 'weep' at about 82K, so I had it replaced. I am anal about not having my bike idle at warm up whether I'm on it or not. My bike jumped off the center stand all by itself on a slight down slope dirt surface one day whilst I was over at a picnic table putting on all my protective gear. Besides, too easy to walk off and end up leaving it run much too long (oldtimer syndrome).

I understand the replacement windows are a new and improved design over original equipment and should last a lifetime.

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I understand the replacement windows are a new and improved design over original equipment and should last a lifetime.

 

Afternoon Red

 

I have seen a few of the new design sight glasses pop out just like the old ones.

 

The new design has a real glass lens so they don't yellow & discolor like the old plastic lens sight glass but that brings on it's own issues.

 

The new design sight glass is VERY EASY to break the glass lens during installation without proper fitting tools so the tendency is to use too much, or the incorrect, lube to install (without using lube there is great risk in breaking the glass at install). Incorrect lube, or remaining lube, on the sight glass can cause them to pop out while riding.

 

Best lube to use on the new design sight glass is Brake Clean but that stuff evaporates so fast that good (re proper) fitting installation tools are need to get the glass in & fully seated before the Brake Clean evaporates.

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Dirtrider,

 

Do you have a picture of an istallation tool? Would like to make one. I also have a new one that I carry with me incase the old one pops out.

 

Evening SAS

 

I have a picture but no dimensions. You will have to size the OD to the sight glass OD & make sure the ID CAN NOT CONTACT THE GLASS in the window. Some use a socket that matches the sight glass OD but trust me, those glass lens sight glasses crack very easily & you can end up with glass shards in your crankcase.

 

As to carrying a new sight glass--very difficult to install on the roadside but if you carry an expandable freeze plug those work great in a quick roadside install.

 

Seal%20Installer_zpsspxnaxyr.jpg

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As to carrying a new sight glass--very difficult to install on the roadside

 

I carry a new sight glass, but it's one of the good old plastic lens units. Actually so is the one on the bike, it's never been changed.

 

My RT is 14 years old (soon to be 15). The sight glass is still clear. Why do some stay clear forever and some get so bad you can't see the oil inside the engine?

 

Stan

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Why do some stay clear forever and some get so bad you can't see the oil inside the engine?

 

Evening Stan

 

Heat, oil varnish, & oil additives can discolor the sight glass lens.

 

My RT's stay nice & clear but my GS's get pretty brown looking after a couple of times getting stuck in 2' deep sand washes & pegging the oil temp getting them out.

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I am going to do three things....

 

1. Put the new sight glass in the freezer for a couple of hours before the install. That should shrink it a bit and make it slide in easier.

 

2. Make a small drill hole in the oil pan cooling fin and run aviation safety wire diagonally across the window. There is a sensor base above the sight glass in the 2 o'clock position and the drill hole in the fin will be in the 8 o'clock. The worst it can do is weep not gush. BMW should do this for critical parts just like aviation does. (are you listening BMW???)

 

3. Carry a 1.5 inch expandable rubber boat plug in my saddle bag.

 

I warmed up the engine for about 2 minutes only long enough for the rpm to stabilize to 1000 at idle but that makes a difference is riding in a 42 degree rain. It's cooling down the sight glass and the engine heat is expanding the metal.

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The glass fell out 1.5 hours into the ride (110 miles from my starting point) but like I said... was raining and could easily be cooling the glass while the engine is dramatically warmer.

 

@Dirtrider: Heating up the glass would secure it in place better not worse. The plug expanding would make a tighter seal. Cooling down the glass would make it looser.... as I mentioned, I will put the sight glass in the freezer before install. They do a similar method to change valve seats and guides in cylinder heads. The valve guide and valve seats are cooled down in liquid Nitrogen to shrink them before installing and it takes a small tap to set them in place...otherwise it would never go into the hole.

 

Probably the best lubrication for insertion either brake cleaner or fluid... or even plain old dish soap but the key I think will be making sure it cannot just roll away like Johnny Applecake and safety wire it down. :)

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...@Dirtrider: Heating up the glass would secure it in place better not worse. The plug expanding would make a tighter seal.....

 

Not so.

The whole bike is 'cold soaked' overnight. So everything in that area would have shrunk. On start up, the aluminium or metalic parts will warm MUCH quicker than the window (whether it is plastic or glass). It is exacerbated because the window is sealed against the engine with a rubber cup which insulates it. So the engine expands and the window lags somewhat. This then allows maximum tolerance differential. If a window is going to pop out, these conditions lend itself to it. Yours however didn't fail this way....or did it? Maybe it all started to move little by little at the start up phase???

 

Question. Once the window has popped out. The oil starts to dump. What is the first thing (for all of you who have experienced this) that makes you realise you have a problem.

You lose a lot of oil. Has the bike seized?

 

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The glass fell out 1.5 hours into the ride (110 miles from my starting point) but like I said... was raining and could easily be cooling the glass while the engine is dramatically warmer.

 

@Dirtrider: Heating up the glass would secure it in place better not worse. The plug expanding would make a tighter seal. Cooling down the glass would make it looser.... as I mentioned, I will put the sight glass in the freezer before install. They do a similar method to change valve seats and guides in cylinder heads. The valve guide and valve seats are cooled down in liquid Nitrogen to shrink them before installing and it takes a small tap to set them in place...otherwise it would never go into the hole.

 

Probably the best lubrication for insertion either brake cleaner or fluid... or even plain old dish soap but the key I think will be making sure it cannot just roll away like Johnny Applecake and safety wire it down. :)

 

Morning Rx_Mich

 

It doesn't work that way, the rubber around the central lens gets softer as the rubber heats so heat make them come out easier. Most seem to come out on the ride following a morning pre-ride engine warm up. I used to see a number of sight glasses come out on first cold days of fall due to engine pre-ride warm up.

 

Same with installing--not enough rubber contraction from freezing to make any difference but freezing makes the rubber harder so it more difficult to drive in.

 

Don't use brake fluid to install as that will effect the rubber surrounding the lens.

 

Best (completely evaporating) lube is brake clean/also per a BMW service bulletin)-- We used to use Windex as that is a great rubber lube but even that leaves a slick film for a long time.

 

The new sight glass is real glass so be very careful on installation or you will have a crankcase with glass in it. The lens runs up under the rubber edge slightly & it doesn't take much contact from the driver to break the glass.

 

BMW did address the sight window retention in the newer boxers (1200 engine) by adding a circlip slot so a circlip can be installed over the sight glass. In fact your new seal will probably have a large circlip in the box, there just isn't enough real-estate in the 1100/1150 engine to cut a slot & install it.

 

On our old off-road GS boxers (pre-circlip) we used to drill 3 small holes 120° apart in the boss around the sight glass then install 3 very small screws & tiny washers to hold the sight glass in.

 

 

 

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@ Ansy S: The first thing I noticed was the engine sounded louder with a muffled sound coming through the now open port hole in the side of my engine.... almost like I had a small gap between the exhaust seat and the engine. I looked in the mirror and saw I was creating a smoke from oil hitting the pipes and muffler. I evenly pulled the clutch, hit the kill switch and let the bike coast to a stop.

 

I didn't want to touch the rear brake at all because if I was losing oil the rear tire could be as slippery as snot. I am glad I did. I probably had 1 quart + remaining in the engine and filter. The engine oil light never came on with the cylinders firing. After 300 mile trip on a trailer home with the port open There was still 3/4ths quart drained. The engine turns over easily so I am optimistic it is still ok. I will need to run it for a while to make sure the bearings are all good. Splitting the filter and inspecting the filter element shows no metal fragments.

 

 

 

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@Dirtrider,

Thanks for the install tips. I saw a pic that someone made an external circlip-like horseshoe and attached it with a 4 mm screw. I am leary of his approach drilling into the case near the sight glass but the front of the case has a couple of bolts that such an arrangement would work have the clip attach there and removing the flat washers or using longer bolts. I will make up my mind which is best after I see how firmly using safety wire will line up along the top of the sight glass.

 

I feel more comfortable drilling a small hole in the cooling fin than the crankcase itself for the remedy.

 

My gut is telling me the sight glass rubber just hardens since the bike spends more time in a cold state versus running so the sight glass eventually will not expand when the oil sump does.

 

My whole point on this post was to advise people to replace this item pre-emptively to prevent being stuck in the middle of no where and risk an engine failure. Few people are aware that there is no safety retention by design. Better to have been forewarned than to react to it afterwards.

 

I guess BMW service is expensive enough as it is for things requiring annual and semi-annual attention. My experience at the dealer is that if it ain't broke don't fix it. There should be enough experience with these old bikes that they are fully aware of things that should be replaced to avoid problems and bring them to the owner's attention as an option to replace. At least you were made aware that failure is possible.

 

 

This the second time this summer, I got caught by a BMW gotcha. The earlier in the season was the bike dying in the rain. Requiring the Hall Effect Sensor to be replaced. $400 part cost at the dealer.... a little more than half of that online. It seems that Bosch that makes the part uses flimsy insulation on the lead wires. Because it gets heat from the engine, the insulation begins to get brittle and crack under the black sheath causing moisture to short out the power and or signal leads. Without knowing where top dead center is, the spark plugs will not fire.

 

The key identifier that this was happening was trying to start the bike, the tachometer was fluctuating wildly. It would cost Bosch and extra $4 to use Tefzel insulated wire which is quite stable to 500 degrees F. They are still using the same insulated wire on their replacements. I kept the old one and will re-wire it with Tefzel wire to keep in the saddle bag. (This is the third HES sensor on the bike so plan on worrying every 35- 45K miles) The more heat cycles and rainy weather you go through increases the likelihood of a failure.)

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The last one was replaced in 2010 and lasted to 2015. Inspection of the leads to the coupling looks like the same insulation and my fingernail will indent the insulation the same as the old. Teflon insulation your fingernail will not be able to do that.

 

I think I will rebuild the old one as a backup just the same. I would still be down for most of the day making a repair but I wouldn't be waiting a week for the new part to arrive. :)

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On our old off-road GS boxers (pre-circlip) we used to drill 3 small holes 120° apart in the boss around the sight glass then install 3 very small screws & tiny washers to hold the sight glass in.

 

DR, how deep did you drill the holes? This is a great idea and one I think I'll do when I'm back home (out of town for a while after a move).

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On our old off-road GS boxers (pre-circlip) we used to drill 3 small holes 120° apart in the boss around the sight glass then install 3 very small screws & tiny washers to hold the sight glass in.

 

DR, how deep did you drill the holes? This is a great idea and one I think I'll do when I'm back home (out of town for a while after a move).

 

Morning Tom

 

Not very deep, I didn't measure the hole depths but used very short screws & just drilled deep enough so the screws didn't bottom out & twist off.

 

 

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When I get the new glass in, I will take a photo of the repair and how I will secure the sight glass in. Yesterday I went to production tool and purchased some 35 thousandths drill bits.

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This the second time this summer, I got caught by a BMW gotcha.

 

So you've had two of the three problems that are sudden, unexpected failures. The other is sudden failure of the in-tank fuel hoses. Since the fuel pump is rated for 3 times the volume needed at full power there can be multiple leaks before sudden failure. The remedy is to replace all of them if they haven't been lately.

 

Others will say that brake lines fail suddenly as well, making a fourth surprise item.

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I have replaced both brake lines in the front. I still need to do the rear. If you feel that your brakes are spongy and it is not air bubbles then check the rubber hoses and you will see that they are soft. When you hit the brakes, part of the fluid is expanding the hose rather than the callipers.

 

Fuel hoses I still need to do as well. I want to see if I can replace the outer lines with stainless braided teflon Aeroquip hose since I have about 20 feet of 3/8ths and put real AN fittings on rather than rely on radiator clamps as the present system uses. If not then new Goodyear rubber lines for sure. I was unaware of hoses inside the tank....thanks for the heads-up.

 

That's what is nice about the forum is to exchange information like this for "preventative" maintenance.... it's far easier to do in your garage than along side the road without proper tools to do the job.

 

I picked up the new sight glass this morning and will make an install tool out of some 1-1/4 inch black pipe. I can lathe it down to make contact with the rubber evenly and not the glass as well as pick up some brake cleaner and fresh oil.

 

Already drilled through the cooling fin below the sight glass and tested some safety wire around the oil pressure sensor on a diagonal to the cooling fin. 30 thousandths stainless wire will prevent a recurrence of this issue. It may weep but no wholesale loss of oil.

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Fuel hoses I still need to do as well. I want to see if I can replace the outer lines with stainless braided teflon Aeroquip hose since I have about 20 feet of 3/8ths and put real AN fittings on rather than rely on radiator clamps as the present system uses. If not then new Goodyear rubber lines for sure. I was unaware of hoses inside the tank....thanks for the heads-up.

 

Afternoon Rx_Mich

 

I would be real surprised if you can find a good way to install braided stainless lines as there just isn't that much room under the tank to install any adapters on the pump pass through then install the stiff lines & route them out. Even then I don't see the gain as they will hook to plastic lines going to the pressure regulator.

 

Remember, inside the tank you must use submersible rated fuel hoses (those cost about as much as braided lines) but the runs are short & the U hose has a very tight bend.

 

No radiator calmps used as you should use special high pressure fuel injection rated clamps, or Oetiker clamps, with a proper tool to crimp them.

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Are these the hoses in question?

 

OEM Parts

 

Will have this done at the dealer since it makes no sense to purchase a $400.00 to crimp two hoses on one bike and not a stable of bikes but at least I am sure the correct hoses are being attended to. :)

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Afternoon Rx_Mich

 

Yes, if you are pre-buying the parts you should probably also get a new strainer (12) & a new vibration dampener (8) as you will probably find the strainer all brown & starting to fall apart.

 

Might as well put a new filter in as long as you are in there.

 

There are also other hoses that run inside the tank that should be replaced --both the tank vent hose & the fuel ring water drain hose run through the inside of the tank (those also need to be fuel submersible & they are an odd size so are very difficult to source outside of BMW (BMW sells in bulk sizes but again expensive)

 

 

You don't need a $400.00 tool as you have other options (shop around the crimp tool isn't that expensive, or with common sense & a good feel you can even use tile cutters.

 

Or you can use special high pressure (full surround) FI hose clamps that have screws on them (these are NOT worm gear clamps or radiator clamps)

1150%20fuel%20pump%20hose%20replacement_zpsefzyzgmx.jpg

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I have updated the photos to show the simplest method and less clumsy looking.

 

 

 

Safety Wire Sight Glass

 

Dirt Rider,

Has anyone in the group made a kit with all the parts to complete the fuel filter change and hose replacement with all the hose clamps? I know sometimes people have done their research and found the parts through suppliers that are equal or better than OEM at a fair price.

 

Also ... I did purchase a Harbor Freight pair of Nibblers and I can grind the sharp edge off to make nice crimpers out of them for $6.00 :)

 

Thanks for the suggestion. :)

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Has anyone in the group made a kit with all the parts to complete the fuel filter change and hose replacement with all the hose clamps? I know sometimes people have done their research and found the parts through suppliers that are equal or better than OEM at a fair price.

 

 

Morning Rx_Mich

 

No one here that I know of but BeemerBoneyard has a sort-of kit but it doesn't contain the vent or water drain hoses (those are difficult to source outside of BMW & come in bulk lengths) that unfortunately one bulk line isn't quite long enough to replace both hoses.

 

That 5mm submersible hose is very expensive so even sourcing outside of BMW is expensive.

 

 

 

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