New camshaft to fix waterpump seal leak????

on my 01 mxc400 , I had a complete set of new seals installed last fiday and the pump appeared to be nice and dry? While sitting at the starting line for the district 37 grand prix last Saturday with the bike idling, I looked down and fluid started spitting out of the weep hole??

I turned off the motor and it eventually stopped leaking.

I went ahead and raced and it leaked a small amount more

throughout the day??? Any ideas?? other than maybe it was a bad seal? or a bad installation from my local shop??

:)

The O-ring is probably leaking around the seal carrier and not the seal and they didn't install it properly.

James is probably right. The stock o-rings KTM sells for the carrier are 2-3 sizes smaller than they should be. I bought a bag of the corect (IMHO) o-rings. When you stretch an o-ring it gets thinner, the further you stretch it the thinner it gets until it breaks. Since the o-ring is stretched thinner on the carrier it is not compressed properly it looses some of it sealing surface and can't hold the pressure as well. I think this is the reason most of the newly replaces water pump seals leak. That's why it will start leaking as the motor heats up and will continue to leak until the motor cools off and the pressure is gone from the cooling system. To test this warm the motor up and note how long it takes before the coolant starts leaking. Let the bike cool and then remove the radiator cap and warm the engine up if there's no leak then the o-rings are probably bad if it starts leaking then the seals are more likely the problem.

You had three bros do it right? Take it back to them.

PS. That race is always one of the dustiest of the series.

This happened to me on my last seal replacement and I squirted a little contact cleaner in the weep hole followed by a lubricating spray. I then LOWERED the coolant level in my radiators to just above the fins and its held for the past 700miles. :)

Cheers

Clark

To test this warm the motor up and note how long it takes before the coolant starts leaking. Let the bike cool and then remove the radiator cap and warm the engine up if there's no leak then the o-rings are probably bad if it starts leaking then the seals are more likely the problem.

While I'm not saying the problem isn't bad orings, I'd think the outside seal would also be more likely to pass fluid under pressure than not, so I'm not sure this test is a very definitive one for telling if you have an oring or seal leak. It wouldn't matter much to me, anyway. I always replace the whole carrier assembly with new orings and seals anytime I have a leak there. Travis, do you know the dimensions of the thicker orings? Did you get them at an auto parts store?

Looks like the dealer screwed something up. It should not leak once fixed. Take it back.

I took it back to 3 bros and now they are saying it needs a new camshaft :) they want another $250 to replace the camshaft and all of the seals.. thats on top of the $125

that I paid on friday. I called Zracing to check on the price of the camshaft and they said that 3 bros used the wrong seal and that its highly unlikely that it needs a

new camshaft.. :D :D Im beginning to think that there is partially one correct word and that is "SHAFT"

It's highly unlikely you need a camshaft. I'd ask them how they determined it was bad. Then post there answer so that we can all understand.

For everyones information, KTM had the o-rings specifically made for them. You cannot buy them anywhere except from KTM.

I work on KTMs all day, and yes the water pump on the RFS are the touchest component of the bike. Most leaks occur from too high of a coolant level coupled with air still in the system, which causes the pump to cavitate and either blow the seal or fry it. So, I use the correct o-rings called out in the parts manual(for the model year) and use locktite on the outside of the shaft seals. I always remove the valve cover as I apply sealant to the o-rings just in case. If you just pull the seal carrier out, you run the risk of insuficent sealing arount the seal carrier. After coolant is poured in I lay the bike on the right side several times to let all the air out, then I bleed the system, engine off, to get the remaining air out. This works everytime! Also, while the valve cover is off, check the valve clearances!

Good luck gang.

Here is my suggestion (I did this myself)-

1)remove the waterpump cover

2)remove the circlip that holds the impeller on and remove the impeller (10 minute job up to this point!)

3)lean the bike over on it's side with the pump cavity partially filled with water/coolant

4)blow compressed air into the weep hole, not too much pressure is needed!

5)Look for bubbles coming from the outside of the seal carrier at the juntion of the rocker cover and head. There is a "T" junction on both sides where it is susceptible and prone to leakage. The 2 castings don't always get sealed well there and the O-ring is all there is around the carrier.

If it leaks around the seals, they may be right about the cam bearings. If it leaks around the carrier, they did a poor job cleaning and assembling it.

----------

At this point, if the carrier is leaking you might use contact cleaner to get it as clean as possible. Then force some high quality sealant (KTM suggests Loctite 515) on the junction and let it set overnight before reassembling. If it works you will save a few hundred dollars and a win the arguement with the dealer. If it fails, you're out a few hours messing with it.

My $.02

James

I agree with OldStroker and Z racing. VERY unlikely that you need a new camshaft. I GUESS what they're trying to say is that if you've eaten two seals that quickly, you could have a bad cam bearing. If a cam bearing is loose, it will allow the camshaft to wobble a bit and take seals out. That is a possible problem but it could just as easily be that the dealer screwed up the install.

In either case, it's unlikely you'll need a camshaft unless the bearing was to completely let go and cause some collateral damage to the shaft. It has not done that at this point or you would know about it. It's accompanied by much loud knocking and banging noises.

Try EVANS NPG+ waterless coolant. It boils at 375+ deg @ 0 PSI. No pressure, no leaks. The hoses are soft even at full operating temp, its amazing. Helped solve my Cannondale heating problems in the woods, great stuff.

Old_Stroker, For everyones information, KTM had the o-rings specifically made for them. You cannot buy them anywhere except from KTM.

Old Stroker's knowledge of KTM's is impressive and for the most part he's always on the money with his KTM assessments but I have to disagree with you on the specially made for KTM only o-ring statement.

The o-rings in question are a standard Buna-N .070 o-ring (or 1/16th inch). O-rings have what's called a dash standard the one KTM uses is a -020 (.8750" id x 1" od). In my opinion the one that should be used is a -023 (1.0625" id x 1.1875" od) or an -024 depending on how tight a fit your comfortable with. You can purchase these at almost any bearing supply house. I bought a pack of 100 for $5. I'll send a set to anybody that wants a set if you'll send me a SASE then you can compare the difference in fit for yourself. With the correct fitting o-rings you can do a carrier change without removing the head.

Travis,

KTM lists 2 different O-rings for the inner and outer sides of the carrier. The diameters are not the same. One is a smaller diameter with a fatter O-ring that needs a little stretching to install on the carrier.

Are you suggesting to match the thicker of the 2, or something different?

I don't sense that anything will correct a slight mis-match between the head and rocker cover other than a sealant, in addition to the O-ring.

James, I just read what I posted and can see where it's a confusing I made it sound like I was using one size o-ring. The larger o-ring is a -024 which is put in before the carrier is installed it will work for both but the -023 will give a better fit for the impeller side of the carrier. I have both and use a -023 for the impeller side and a -24 for the bearing side of the carrier.

Travis,

Email me, please. Address in sig.

BTW, am I missing something? Where'd the PM stuff go?

Travis Wrote:

"Old Stroker's knowledge of KTM's is impressive and for the most part he's always on the money with his KTM assessments but I have to disagree with you on the specially made for KTM only o-ring statement.

The o-rings in question are a standard Buna-N .070 o-ring (or 1/16th inch). O-rings have what's called a dash standard the one KTM uses is a -020 (.8750" id x 1" od). In my opinion the one that should be used is a -023 (1.0625" id x 1.1875" od) or an -024 depending on how tight a fit your comfortable with."

Travis, if you review the part manual for 2001 RFS page 10 you will see that KTM specs the O ring as 25.12 X 1.78, if you convert to English and subtract for the ID you will see that the nominal O ring you suggest is close, but not exact, KTM's is .988 od X .848 ID X .070, yours will stretch and maybe work, but our math told us to purchase the stock KTM parts.

We did some checking tonight, we placed a small and large KTM O ring on a 2003 carrier and measured the final OD and believe it or not, stretching the small O ring over only has a .001 change in final OD. Look like either oring would work in either case ?

Bob

Travis, if you review the part manual for 2001 RFS page 10 you will see that KTM specs the O ring as 25.12 X 1.78, if you convert to English and subtract for the ID you will see that the nominal O ring you suggest is close, but not exact, KTM's is .988 od X .848 ID X .070, yours will stretch and maybe work, but our math told us to purchase the stock KTM parts.

Stroker, metric O-rings are measured by width (1.78) by Id (25.12). There is no true metric o-ring with those measurements. The standard for o-rings is set by Aerospace Standard AS568a and are designated by dash numbers i.e. -20 which is what KTM used. Their measurement of 1.78 x 25.12 is converted from the dash standard specified .988 od X .848 ID X .070 and is the exact AS568a measurement for a -020. It make sense that an o-ring would have a slightly smaller ID than the shaft it is used on. Thus a .988 ID would be used to seal a 1" shaft. For general use purposes o-ring measurements have been rounded up or down for ease of description.

yours will stretch and maybe work, but our math told us to purchase the stock KTM parts.

This doesn't make sense when you consider KTM calls for a 25mm ID o-ring and then stretches it 20% around a 29.38mm groove (which is what the o-ring slot of the carrier measures). The proper o-ring would actually be a -023 (ID 1.125" or 28.58mm), which is a lot closer to the carrier’s actual size. I have been confused by KTM's reason for using and o-ring thats too small in the first place.

When you over stretch o-rings and then subject them to high tempature applications they will have a higher failure rate than an o-ring that is properly sized.

Bottom line is either o-ring will work and we've both spent way to much time on this.

What ever o'ring siezes you decide on Try the ones made out of flurocarbon,known as Viton.(usually brown in color). They have a higher heat rating 400+deg. as buna is 240deg.Don't use urethane,they are not compatible with water/antifreeze. They are availble at a hydraulic shop or bearing supply.

forfun.jpg

Travis, Yes we agree, way too much time....

Travis is right, the whole idea of an oring sealing is to have an interferance fit or crush as it is known, therefore the oring needs to be selected to fit the shaft WITHOUT excessive stretching in order for it to seal on the periphery!

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