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KTM Thumper Discussion

2008 450 EXC. No fan installed. Bike is motarded.

While riding on Sunday I saw antifreeze here(see pics). Not a lot of it, but certainly enough to notice.
How concerned should I be? It was before noon, so not the hottest part of the day. We had been riding at elevated speeds and earlier in the day I had to sit at a light and thought I could smell antifreeze.

The water pump casting, where your leak is, on your bike has a "weep hole". Anti freeze will leak out of the hole whenever the water pump seal fails. Most likely your outer WP seal has failed. It is a fairly common occurrence of your model of KTM. It is not a difficult repair if you know how to extract a seal and drive a new one in properly without damaging the new one.

Your bike does not hold much antifreeze to start with. Even a small leak like what you have can cause you to be short on coolant in a short time period. These motors are pretty tough but heat abuse will take its toll.

In your last picture, you can actually see the indentation of the weep hole from the side. It is right in front of that bottom bolt. You can do an easy visual inspection, but since you posted nice clear close ups, I would say from my view 350 miles away that you need to replace your outer WP seal.
 
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Not hard to do:

08-11 KTM 450-530 Water Pump Seal Replacement How-To
https://advrider.com/index.php?threads/08-11-ktm-450-530-water-pump-seal-replacement-how-to.769378/

Lots of pics with detailed descriptions.

There is an upgraded impeller for the water pump as well. If you are going to be replacing the seal, you might as well do the upgrade while you are in there. It gives you more flow capacity. Here is the one I used for my 530 EXC,

https://shop.cyclezone.com/ktm-sxs-water-pump-kit-detail.htm?productId=24971836

The impeller is taller than the stock, so that orange ring piece fits between the engine case and the pump cover to give more room. After installing this pump, I did notice that my fan tends not to come on as often or for as long as it did before.
 
The water pump casting, where your leak is, on your bike has a "weep hole". Anti freeze will leak out of the hole whenever the water pump seal fails. Most likely your outer WP seal has failed. It is a fairly common occurrence of your model of KTM. It is not a difficult repair if you know how to extract a seal and drive a new one in properly without damaging the new one.

Your bike does not hold much antifreeze to start with. Even a small leak like what you have can cause you to be short on coolant in a short time period. These motors are pretty tough but heat abuse will take its toll.

In your last picture, you can actually see the indentation of the weep hole from the side. It is right in front of that bottom bolt. You can do an easy visual inspection, but since you posted nice clear close ups, I would say from my view 350 miles away that you need to replace your outer WP seal.

I suspected that would be the case, thanks for the quick reply!
 
Not hard to do:

08-11 KTM 450-530 Water Pump Seal Replacement How-To
https://advrider.com/index.php?threads/08-11-ktm-450-530-water-pump-seal-replacement-how-to.769378/

Lots of pics with detailed descriptions.

There is an upgraded impeller for the water pump as well. If you are going to be replacing the seal, you might as well do the upgrade while you are in there. It gives you more flow capacity. Here is the one I used for my 530 EXC,

https://shop.cyclezone.com/ktm-sxs-water-pump-kit-detail.htm?productId=24971836

The impeller is taller than the stock, so that orange ring piece fits between the engine case and the pump cover to give more room. After installing this pump, I did notice that my fan tends not to come on as often or for as long as it did before.

Thanks for the links!
 
Let the build begin:

IMG_1795_zps6pyalr6o.jpg

Easy man, this is a family site. That picture is pretty racy....

Figured I'd better say *something* on TWT since I'm hanging out in Bastrop this week. Holy crap how do you guys ride down here? It's like walking around in a blast furnace with water injection out there....
 
Easy man, this is a family site. That picture is pretty racy....

Figured I'd better say *something* on TWT since I'm hanging out in Bastrop this week. Holy crap how do you guys ride down here? It's like walking around in a blast furnace with water injection out there....

Bastrop huh.... and you didn't ping Rusty or me to get together? How long you in town for? Brew stuff?
 
Down here for my contract gig work. It's a total man camp - I eat, sleep, and work on the facility and I don't have any transportation, so my visiting is limited. I might have to catch you guys next time, I fly out on Saturday.

J
 
Howdy. Glad you still keep an eye out for us. You're right about the heat.
 
Holy crap how do you guys ride down here? It's like walking around in a blast furnace with water injection out there....

Come on over here to East Texas. Instead of the blast furnace, its like sitting in a crock pot with a wet wool blanket over your head... :-P

It will just make you appreciate Wyoming all the more... until it is 20 below back home :eek2:
 
Check your FB Messenger.... WoodButcher and I would be happy to run down to Bastrop this evening for a burger and beer if you're up to it. :eat: :chug:
 
So this can’t be good...

67eeea32cf7259e492c6917d7ff67eb3.jpg


I thought I might get lucky and sneak in a ride between thunderstorms today. The bike has been sitting sine the end of July after I returned from a trip to Ouray. It ran like a dream during the trip! So today, I turned on the gas, cranked it a few times, and it fired right up. I let it idle for a few minutes while I ran inside to put my boots on. I came back out to see a puddle of oil on the concrete under it, all down the side of the engine, and in the bash plate. I immediately shut it down. It was hissing and bubbling right at the valve cover gasket on the left side (shown in pic). It has about 12K miles on it and has been trouble free.

I am hoping it is just a bad gasket and a new one will take care of it.

Thoughts?
 
After sitting it then begins leaking that much at idle? From the valve cover? How much oil is left in the motor?

If it were me, I'd wash it thoroughly, fill it with oil, start it and verify where the leak is.

That just looks like a lot of oil for a simple leak after 10 minutes of run time and from a valve cover gasket. The top end is lubed from squirters and splash as I understand it ... it's not under any oil pressure.
 
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With it running on the side stand oil will puddle up at the valve cover seal so it could loose a good amount in a short time.
The odd part would be the sudden failure of the seal. I would check the crankcase breather and make sure it is not pinched or obstructed in anyway. In the event that it is not venting it will make a vent of its own.
 
Where is the breather locate? Valve cover?

something has to be pushing the oil out
 
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You need a bigger car

Sent from my SM-G900V using Tapatalk
 
This worked out good. Averaged about 28+ mpg. Our old Tahoe might have done .5 of that
 
Gonzales, coushatta ,Harvest Alabama to get the bike ,Nashville, Memphis, coushatta , back home tomorrow .
 
Where is the breather locate? Valve cover?

something has to be pushing the oil out

The breather is on the crank case, but if not venting it could blow the valve cover gasket. The swept volume on any of the KTM 5** series bikes is large compared to the free space in the case. When the bike is upright you might not notice as it might be minimal as the oil is draining back properly and only a little mist will come out of the valve cover, but on the sidestand oil will pool above the gasket line and the crank case pressure will then push a flow of liquid.
 
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The breather is on the crank case, but if not venting it could blow the valve cover gasket. The swept volume on any of the KTM 5** series bikes is large compared to the free space in the case. When the bike is upright you might not notice as it might be minimal as the oil is draining back properly and only a little mist will come out of the valve cover, but on the sidestand oil will pool above the gasket line and the crank case pressure will then push a flow of liquid.

May not have time to mess with it until I get back from the TWT Ark rally. Leaving early Wednesday and will be back Sunday night. I will let you know what I find.
 
Here is mini me ...

Installed:

Probend
Seat Concepts
EE skid plate and rad braces


Need to get out and shake it down a bit.
Plan on Big Bend this winter

Undecided on the small case out back.

Also can't decide if I want to get a larger gas tank
a7a3c8885ec9c9daa78672bd6dc11525.jpg


Sent from my SM-G900V using Tapatalk
 
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