[LeDude]

I think my 650 has decided to break down every Saturday, at least this time it happened at home.

I started the scoot in anticipation of running a few errands and I knew right away that something wasn't right as
I could smell the faint smell of engine oil. Bent down to check and yup was greeted by a small pool of oil.

Shut the engine off and started scratching my head, what now?

I thought that my replacement oil level sensor was leaking but I think I was wrong as I can see how the oil would
drip its way down and pool around the oil level sensor giving one the false sense that it was leaking.

Had to remove the muffler so I could get a better look at where the leak was, am getting pretty good at dropping that thing.

A few pics to show where the source of the leak and a video.

Haven't hit the service manual yet as I have to leave to run these errands.

Would appreciate any thoughts, suggestions, diagnosis from the experts on the forum.

Thanks.....

The leak seems to be coming from where the water pump is, but I could be wrong.

[youtube:3f1n0f19]i2ixThaUXyw[/youtube:3f1n0f19]

 

[cyclechamp1982]

I'm curious...any update on the problem? Sounds like something "unusual".

 

[Buffalo]

It's probably leaking from the seal on the engine side of the water pump. Robin's did that on a ride a few years back.

The water pump has two seals on the shaft. One is on the pump side and it keeps water from going into the crankcase. The other is on the crankcase side and it keeps oil from getting into the coolant. Between the two seals is a small chamber and there is a hole drilled into the bottom of it. If either oil or water gets past their respective seal they will run out through that hole.

On the good side it's a quick and simple job to pull the water pump. It's possible to take the pump apart and replace the seals and shaft if it is worn. Robin just elected to put a new pump in her's and I helped her swap it out with the bike up on the lift in my shop. I've still got the old pump in a box on the shelf in my shop. I intended to get the parts and rebuild it but never got around to doing it.

 

[TwoWheelTim]

I think Buffalo nailed it. I had the same thing happen on another scooter, but it wasn't leaking as quickly as yours. Emergency fix is to ram a strip of silicone tube into the weep hole to stop the leak. It will get you home, I know because it worked for me for over a week.

So sorry to hear of your continuing trials.

 

[ErikDK]

I thought LeDude had given his scoot the name "Rip" :lol:

 

[TheReaper]

If it means any thing I feel for ya . good luck !

TheReaper!

 

[LeDude]

It's probably leaking from the seal on the engine side of the water pump. Robin's did that on a ride a few years back.

The water pump has two seals on the shaft. One is on the pump side and it keeps water from going into the crankcase. The other is on the crankcase side and it keeps oil from getting into the coolant. Between the two seals is a small chamber and there is a hole drilled into the bottom of it. If either oil or water gets past their respective seal they will run out through that hole.

On the good side it's a quick and simple job to pull the water pump. It's possible to take the pump apart and replace the seals and shaft if it is worn. Robin just elected to put a new pump in her's and I helped her swap it out with the bike up on the lift in my shop. I've still got the old pump in a box on the shelf in my shop. I intended to get the parts and rebuild it but never got around to doing it.

Thanks Craig, appreciate the input, was hoping you would chime in on this one as I know you know just about every seal and o-ring on the 650.
Quite encouraging to know what needs to be replaced, I was suspecting a seal of sorts that had gone bad. Looking at the parts microfiche, your
explanation makes perfect sense.

I didn't know about Robin's failure, poor thing seems to have suffered every possible failure on her 650.

I did remember a few water pumps leaking coolant but could not remember an instance where oil leaked.

Was a bit worried about having to remove the frame to get the pump out as it sits right next to it, but based on your experience, I may be able to
get it out without having to take the scoot apart again.

Will be a day or two before I can get to it, step one would be to take the pump out for inspection.

A new one costs about $170.00. Replacement parts will cost about $30-50.00. I am thinking about replacing all the O-rings on it.
I will know more once I take it out and can make a determination as to the state of the other components of the water pump.

I took a quick look at the service manual but haven't memorized it and committed to memory yet.

Does one have to remove the bearings in order to replace those seals, coolant and oil.
What would your recommendation be, replace it or rebuild it?

thanks a bunch as usual.

Thanks to all others for commiserating with me, the price one pays for keeping a older ride.

 

[Buffalo]

When we pulled Robin's waterpump the only thing we had to take off was the lower frame cover. We did take the bolts that hold the floorboards to the brackets loose so we could push them up a little to get more clearance. You have to wiggle the pump a little to clear the frame but not to much.

As for replacing the seals, I'm not sure exactly what the procedure is as I never got around to rebuilding Robin's old one. I remember that when we pulled it out I couldn't tell just by looking it exactly how you would get the water pump side seal out to gain access to the oil side seal behind it. I'm thinking that you would have to pull the bearings out and work at it from the back side.

 

[MJR]

Like Buffalo said, simple fix, though it just seems like another thing gone wrong, once fixed the joy of the Burgh shall return.

 

[needtoride62]

LeDude,

Sorry to see this happen to any Burgman owner. Maybe it's just your scooter, asking for even more attention than normal. I can see that you have added
some thermal protection to a coolant line. I think he/she is spoiled. This oil leak looks like it could be a very time consuming project. We will be
reading this forum to see how you make out.

Alan

 

[Buffalo]

LeDude,
This oil leak looks like it could be a very time consuming project. We will be
reading this forum to see how you make out.

Alan

If he just elects to replace the pump with a new one then less than an hour job. Of course that will be split by a wait for the new water pump to arrive between pulling the old one and installing the new one.

 

[MJR]

As for replacing the seals, I'm not sure exactly what the procedure is as I never got around to rebuilding Robin's old one. I remember that when we pulled it out I couldn't tell just by looking it exactly how you would get the water pump side seal out to gain access to the oil side seal behind it. I'm thinking that you would have to pull the bearings out and work at it from the back side.

It seems to me if he is not getting and mixing of coolant and oil he should only have to remove the housing (similiar to a car distributor) from the engine case and clean/change the o-ring or gasket between it and the engine case right?

I can see that you have added some thermal protection to a coolant line.

As far as I know they all should have the heat shielding on the hose to shield it a bit from the exhaust.

 

[Buffalo]

It seems to me if he is not getting and mixing of coolant and oil he should only have to remove the housing from the engine case and clean/change the o-ring or gasket between it and the engine case right?

Given the amount of oil he is seeing I'm pretty sure the leak is occurring on the seal on the shaft that drives the waterpump impeller. I don't think a leak on the o'ring that goes around the outside of the pump housing would leak that bad. He can tell for sure by looking under the bike up at the bottom of the pump and watching the weep hole in the pump housing when he starts the bike.

Oil and water won't mix because anything that leaks past the oil seal or water seal drains out the weep hole in the housing between them. You have to take the pump apart to get to the seal. If you look at this fiche the oil seal is number 7 and the water seal is number 5. http://www.partshark.com/fiche_section_ ... fveh=10159

 

[MJR]

Possible too. Since it has to be pulled out either way it could be inspected then and at that point since your in there either replace or rebuild it all, won't get a better time.

 

[Buffalo]

I went out and found Robin's old pump and took a couple of pictures to show you what I mean. As usual the pictures are not perfect as my camera doesn't have a close up lens.

In this photo you can see the weep hole from the outside. It is that little dot on the shaft housing between the black o'ring and the back of the impeller housing. When the pump slides up into the crankcase it doesn't fit up tight to the crankcase so the hole is left exposed.

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I went ahead and pried the water seal out so you could see it from the inside. Right behind my thumb you are seeing the back of the oil seal. If you look closely you can see a black dot through the housing in line with the end of my thumb. The water side seal ends before you get to the hole. There is a gap about 3/16 inch wide between the back of the water seal and the back of the oil seal.

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[Buffalo]

Looking at the impeller shaft on this pump there is quite a bite of scaring on the shaft where it fits through the oil seal. I don't think it would seal right even with a new oil seal installed so a new impeller would be required too. As I remember back when we added up the cost of replacing all the seals and the impeller we were looking at $80. The manual also calls for a special tool to get the water side seal out that I didn't have. We tried just prying it out without much success. I think that was the point that Robin just decided to go ahead and get a new pump.

The special tool is just a small bearing puller so if you have one of those you should be able to get it out. Since at this point I'm not real interested in rebuilding this pump I just used a bunch of brute force to pry the seal out. Destroyed the old seal and scratched the housing a little but I think I could dress it up with some emery cloth and install a new seal in it with success.

 

[Buffalo]

The only other place it could be leaking oil around the water pump is that large o'ring you can see around the shaft housing in my first picture. It's about 5/8 inch out from the back of the impeller housing.

As I mentioned above, the best way to determine which place it is leaking is to get you head up under the bike where you can see the weep hole then wipe all the oil off and have someone start the bike. If it's coming out of the weep hole you will see it right away. As near as I can tell looking at the lubrication schematic in the manual oil flows up through the shaft bearings under pressure. There is another hole up in the small part of the shaft housing to let the pressurized oil drain back to the crankcase. So if that seal leaks you get a lot of oil out past it. When Robin's started leaking it pumped about a quart of oil out in a couple of miles. It doesn't look like the area around the o'ring would be under pressure so I don't think it would leak like that.

 

[TwoWheelTim]

Yep, that is how they work, good write up Buffalo. My pump design is almost identical. There are two seals one for water and one for oil. That is why my temporary remedy worked quite well. I think you would at a minimum need to replace items 3,5,7 and all the other O rings shown on the fiche. I didn't want to mess with pulling the tiny seals in aluminum so I acquired a new pump for my scooter.

Although $170.00 for that pump is just ridiculous expensive, so I might be tempted to disassemble first and order parts later.

Best of luck.

 

[TwoWheelTim]

Here is the hole, on my other scooter.

 

[LeDude]

Thanks one and all for your thoughts and input.

Very special thanks to Buffalo for all his insights and perfect understanding of all things 650.
Greatly appreciate you taking the time to take your spare water pump assembly apart and provide the great
explanations and pics.

The oil leak seems to emanate from where the water pump comes into contact with the engine casing.
I am guessing that either the seal or o-ring got brittle for sitting for close to a year without any oil in the engine.
I had to dump the engine oil as it kept leaking like a sieve.

I spent some time going over the service manual to educate myself about this particular assembly and all its parts.

I also crunched some numbers and put everything into a spreadsheet to see the pros and cons of rebuilding the assembly
vs buying a new one.

A new pump assembly costs anywhere between $150-170.00 average online, and I am sure my local dealer will match those prices.

Parts for a rebuild could be anywhere from $30-100.00 depending on whether one replaces the bearings. I personally would
replace everyting, all the o-rings, bearings, the mechanical and oil seals.

From what I have been able to understand thus far from the service manual, you don't have to remove the bearings to swap out
the oil and mechanical seals. The oil seal sits goes on top of the outer bearing and the mechanical seal goes over the oil seal.

I put together my preliminary DIY on how to remove and service the water pump, I base all my DIYs on the service manual steps
and expand on it if necessary. You can check it here:

DIY - Water Pump Maintenance

-- Water pump housing

the weep hole is very visible in the housing picture.

-- Inner bearing

-- Oil Seal

-- Mechanical Seal

-- Impeller

- O-Rings

- Cover O-ring

I am off to the hardware store to buy some supplies to build a flat bed/platform for my HF Motorcycle lift, getting tired of crawling on the floor to work
on stuff under the scoot.

Will post my decision on whether I am going to rebuild the water pump with new parts or buy a new one.
The special tool for removing and installing the bearings seem manageable and one could come up with some DIY Tools.