waterpump bearings and seal placement

My 84 wr400 leaks trans fluid out the weep hole under the water pump. I had the sealed bearing in first and the open bearing in last. My thinking was trans oil gets to the open bearing for lubrication and the sealed bearing keeps the trans fluid in the case. Which way do the bearings go in? The case looks good so I don't think the fluid is getting around the bearings.

Does the seal for the water pump go with the numbers facing the crank or out facing the impeller?

Also, does anyone know the minimum measurement for the clutch fibers?
My clutch slips in higher gears.

mine does too, i clean it off every so often. mine isn't much of a weep and I don't worry as long as the coolant doesn't mix with the gearbox oil...so far so good.
do you have a parts / wkshop manual? good sources. I use ATF - F which helped the clutch a lot as it used to slip (its knackered) it was well soaked in coolant when I got it and I scrubbed it (plates) with wet and dry in petrol. I have also had good results (less slipping) with Briggs and Stratton 20 wt oil

So far no coolant mixing with the trans. I use type F also. I don't know the history of the bike, I just picked it up last fall. I just found the correct parts list on Halls web site. It looks like I had the bearings in correct. I don't have a repair manual. It only leaks while on the side stand. Thanks Suprize.

It helps to have one you have not taken apart yet. I bought those bearings from a husky supplier so they came with part numbers. ( had this discussion with Halls at the time I ordered the bearings and whatever else was on my shopping list, I may or may not have followed the comments) My thinking at this time would be that the seal is to keep the water in the right place. The circular spring in the seal would go towards the water. I would think the open bearing is closest to the crank, I think I pried off one seal on the other and packed it with water proof grease and put the seal back. It is not really a seal with a spring of course. The idea of just removing the seal towards the crank did cross my mind. The oil does not seem to come out if the level is a bit lower or the side stand is not used or maybe used with a block under it. Just from memory. I seem to notice the impeller wearing against the water pump housing. even though it is spinning at crank speed not less like the modern stuff the size is so small as not to come close to compensating. Then with wear, it must be like $200 for an impeller and housing by now......I think someone made metal housings at one point, for more $ than a new water pump for the hauler.....


fran

For amusement I will discuss that shaft the impeller attaches to and goes through the bearings and slots into the crankshaft at the threads. Of all the engines (I have apart) that are water cooled one has that shaft that gets thin, like the diameter of lead in a wood pencil perhaps and that goes into a pocket in the housing. I wanted another new one like that but apparently that was only on the first ones and has been superceded by the one I have lots of but in varying states of less than ideal. Another (a new one from the proper parts supply chain) shaft that is the size of a five or six inch long common nail but shorter was $60 at the time.

This case is a newer aluminum case. The original for the bike did have the longer shaft that extended into the outer water pump housing. It also had only one bearing. The mag case is in pretty bad shape. It was badly corroded at the pump and also broken and repaired by the kick starter.

Just because the 87...88 cover has the larger clutch cavity and inserts at the shift and kick spots does not make the material aluminum. I have no aluminum covers.

slip in the higher gears as opposed to slipping at lower speeds and initial engagement is usually a "holding power" issue, i.e. springs...

The cover I have is not magnesium, the original cover is. What would it be if not aluminum?

A spring loaded carbon seal is far superior to a radial rubber seal for water. Once you understand how it works and what it needs to function . All decent jet units for boats are carbon seals and I think they have a bit more risk involved than a bike water pump

My copy of the workshop manual says the fiber disk is 3mm thick. Hope that helps!

thanks Brad

I can not tell you that long distance. I do the file a bit and then wave a tiny oxy fuel flame over the chips and see if they catch fire test to verify magnesium. I am not saying your cover is not aluminum or more accurately an alloy of aluminum. Just seems pretty common assumption on here the later origional covers were aluminum or aluminum alloy. Perhaps they did change the alloy or casting method or use a different supplier. I know a guy with an 1985 ktm that had horrible corrosion and I believe he stated he got replacement cases under warranaty. Perhaps like the clean air compliance attempts that ended up with the butter head label around 1965 for BMW bikes and the vw heads around that era cracked between the spark plug and a valve seat recess. There may have been aluminum replacements in the Cagiva era, just I have no covers that fail to test as magnesium alloy using my method. Have an 87-88 one that is corroded in the water pump area as well. Today's anti freeze may well have better additives then back then.

As I have mentioned before, I have concrete tools outside under the porch bull float and screed that do not corrode but the welding rod for cast magnesium gets white deposits on it inside the house.