Water pump and/or linkage failure

[Maddog Reynolds]

This is the third 2016 bike I have come across with the water pump related problem, all within the first 300km. Mine has only 200km on it. Really poor build quality I must say


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By the way Streetfighter, my 2015 bike recommends OAT coolant, Motorex 3.0, which is pink, so I guess your 2016 does as well. Apparently, a lot of bikes came with ethylene glycol-silicate coolant. And from the colour yours did too.

Could that be causing the pump seals to fail early? Because I have an idea that a lot of gasket failures are caused by low coolant level (caused by water pump seals leaking).

 

[Seth]

I should start bringing bags of burning shit every time that I visit my dealer now.

Ha ha lol that one made me laugh!!

 

[streetfighter]

By the way Streetfighter, my 2015 bike recommends OAT coolant, Motorex 3.0, which is pink, so I guess your 2016 does as well. Apparently, a lot of bikes came with ethylene glycol-silicate coolant. And from the colour yours did too.

Could that be causing the pump seals to fail early? Because I have an idea that a lot of gasket failures are caused by low coolant level (caused by water pump seals leaking).

I don't know. Since I use my RC on the track only, my dealer was supposed to fill the radiator with water instead. The mechanics must have forgotten. Water will be used from now until winter storage


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[Deleted member 452]

Ha ha lol that one made me laugh!!

My work here is done.

 

[streetfighter]

My work here is done.

[emoji106][emoji106][emoji106]


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[Maddog Reynolds]

Water will be used from now until winter storage

I must confess I don't understand that. Water and hot aluminium alloy react, and you get electrolytic corrosion if there is any different metal (such as a steel bolt head) in contact with the alloy. I'd want corrosion inhibitors In there all the time, hot or cold.

I know truly distilled water will reduce the rate (most "distilled" water I see isn't, it's only de-ionised) but there is always some reaction.

 

[streetfighter]

I must confess I don't understand that. Water and hot aluminium alloy react, and you get electrolytic corrosion if there is any different metal (such as a steel bolt head) in contact with the alloy. I'd want corrosion inhibitors In there all the time, hot or cold.

I know truly distilled water will reduce the rate (most "distilled" water I see isn't, it's only de-ionised) but there is always some reaction.

Unfortunately that's the rule from the race series I am in. I don't have a choice


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[Maddog Reynolds]

Correction, I was thinking of the other KTM, LC8 water pump rebuild.

The inner seal is in the engine case. so yes it is pull the engine and split cases.

View attachment 4142

I am sorry to keep asking questions, but is there any difference between the two seals, or the way they are fitted? Or is it just "belt and braces", that coolant has to leak past 2 seals to get into the crankcase?

I have a friend in an engineering company who is looking for a tougher seal, but I can't have my bike off the road for long, which I will if I take it apart for inspection before I have new spares.

I'll start a new thread if he finds anything really good.

 

[Fasteddy]

The seals are the same part, they are installed in opposite direction of each other so one is containing oil in crank case and the other coolant, From what I can tell they are a low grade seal and not a higher temp rated one like that used on my LC8 SuperDuke, 212deg. F vs 700 deg F, I think mine is slowly leaking now and I started searching for a 12X24X5,5 seal of higher temp rating but they all seem to be 12X24X6 or 12X24X7, the last number is how thick it is so until I have it apart and can see what kind of clearance there is I an not sure what can be made to work / substituted.
Another point is that there is a removable collar / sleeve called out as #9 on the diagram and included with the rebuild kit, on other KTM's including the LC8 a common issue is the shaft being worn where the seal rides on it. The design of the 390 engine seems to have the sleeve incorporated so that it can be replaced as the seal wears on it.

FWIW, this is the seal used on the LC8 which is a Teflon spring high pressure / temperature.

0760123073 SHAFT SEAL RING 12X30X7 PTFE DOUBLE-LIP

 

[Maddog Reynolds]

The seals are the same part, they are installed in opposite direction of each other so one is containing oil in crank case and the other coolant

I've ordered the proper repair kit.

Looking at the exploded diagrams, I can't be sure but it seems that the flat sides of the two seals are facing together, with the hollow sides facing out. Others have said the *flat* side of the outer seal faces out (they don't say which way they expect the inner seal to be) and I have seen a rushed YouTube vid of a 200 Duke being fixed that way.


Perhaps the repair kit will give clear instructions.

edit: In my humble opinion, 212°F is pants. The cooling system gets close to that idling before the fan turns on and it can get a lot higher with recommended coolant and pressure cap

 

[Fasteddy]

Your exploded view is very interesting as it calls out the bushing and mandates its replacement which makes sense, Does it call for a different part number?
Do you have the URL for that exploded diagram?

Yes the flat sides of the seals face each other. the side of the seal that contains the pressure / fluid is the side with the spring around the lip, this is confirmed in the service manual, same on LC8 and numerous data sources from seal manufactures.

 

[Maddog Reynolds]

That's what I expected, with up to 20 psi cooling system pressure. It makes sense to have the pressure hold the seal lip against the shaft. But others have told me it's the other way around. Weird.

The pics I found in Google images searching for:
KTM RC 390 water pump

https://www.google.co.uk/search?q=KTM+RC+390+water+pump

I can't find the same link now!
edit: I may have posted the wrong image above, not a 390. Sorry.

 

[Fasteddy]

I may have posted the wrong image above, not a 390. Sorry.

No, actually that image is very telling in that it points out changing the sleeve that the seal rides on. On the LC8 water pump there is a revised hardened shaft and seal and even at least one after market shaft and seal kit.
I have an industrial parts distributer working on sourcing a more appropriate replacement seal.

 

[Maddog Reynolds]

For completeness, this is the repair kit I ordered, which includes the seal sleeve and an O-ring. I can't visualise how the O-ring seals the sleeve, but I'll see soon enough when the parts arrive.

 

[Michelle]

Where did you buy the repair kit from Maddog ?... Does the outer part of that sleeve turn like a bearing ?, because from that picture it looks like there is an inner part...
I could not get mine off , it was stuck..

 

[Fasteddy]

Here is the part number listed in PartsFinder for the US RC390....

90135055010WATER PUMP REP. KIT DUKE

 

[Michelle]

I have ordered one from my local KTM dealer.. Be here Friday....

 

[Maddog Reynolds]

I ordered from Fowlers (same as you did for the seals, I think). Hundreds of miles south from here, but I used to visit their shop years ago

 

[Michelle]

Yeah I did Fowlers , I must of missed that kit M..... How much did you pay for yours ? , I have paid £31 for mine... And I looked at my pictures ,, that sleeve bit looks like its fixed and not bearing type...

 

[Maddog Reynolds]

I haven't taken mine apart yet, but I'm expecting the seal sleeve to come off with a bit of persuasion. I'll report back if I have any surprises

Yes I paid £31 and some pennies, plus P&P. I also ordered spare seals, so I have a couple to show engineering supply people and/or as spare parts ready for next time

Also I'll be flushing with distilled water and filling with recommended Motorex M3.0 (OAT) coolant, unless anyone can see a problem with it? I ride in a temperate climate (northern UK) and overheating has never been a problem. But I may fit a manual fan switch, so I can do the last 1/2 mile with a cooler radiator and reduce system pressure when I switch off.