KTM LC4 (640) Thread Index

Pull air +1

M.

Now I think about it if you put the fan on the front of the rad it should push air through the rad... :huh
Too much beer again...

What??????? No Ouzo or Retsina???

Cheers

Droptarotter,

So right!!






Just let me add.

KTM might be able to design a PD racer but sidestands and centerstands give them trouble.


bill

Hi there. I wanted to get my bike licensed today but when I took my bike for a ride the lower radiator hose popped off. I got it home, tightened the hose back on and added some distilled water. I leaned it over side to side, trying to get rid of any air pockets and then ran it with the radiator cap off for a while. Topped up the with a little more water until it just covered the fins. When I took it for a ride again the same hose in the same place popped off. Has anyone had this happen before or know what might be causing pressure to pop the hose off?

I want to get it right before I add good, expensive coolant again. Any advice would be much appreciated..

Two things out the top of my head, either the hose clamp does not apply enough force to hold the pipe in place and as pressure builds up it slides off or if the engine temp was above normal the radiator cap should open and let some water out to relief the pressure . If not then the system will fail at its weakest point which is probably in your case due to my first sentence this hose...

I would change hose clamp to begin with, fill it with distilled water, let it idle until the radiator fan pops in, then see what happens and proceed accordingly :huh

D.

Thanks to all those who have contributed, and continue to contribute and maintain this thread. I am new to Team Orange, having recently purchased a 2000 640 E, with a bunch of 640 A additions. I am prepping the bike for CO/UT TAT riding this June. I had the bike delivered while in Afghanistan, and have just a couple weeks now, and a few weeks when I get back to make sure everything is good to go before the trip. So thanks for this thread and all the great pictures and advice, they have helped out quite a bit already.

Kyle

The hose clamp in that area might be too long and bottoming out........it might look ok, but might just be a few twists short of proper tension.
Another thing that pops into my pointy head is if the rad cap is the correct pressure??
On these bikes coolant level should only be 10mm above rad core...........if topped up to bottom of filler neck..............they will puke the excess coolant out.

Cheers

Mine did the same in the middle of the forest during a dual sport. Overeating badly, the dash flashing, I limped it to lunch thinking I was abusing it on a hot day on single track.

Didn't find out til we stopped that I'd ridden 30 minutes+ with no fluids.

I had that happen. In my case, I was dealing with a faulty radiator cap and what I thought was a head gasket going out! Turns out the cylinder threads for the headbolts were going south. Pressure frome the compression was entering the cooling system and over pressurizing it!

The big sign I saw besides always running low on coolant was if it sat idling with the cap off it always had small air bubbles coming up to the top of the radiator!

It was obviously a snake you were using.

Mine vibrated loose. Loctite is your friend.

Thanks guys. I think it might be a similar case as low594 said. It was bubbling with the cap off. I have never had this happen before. I did try tighten the clamp as well as I could, thought it should have been tight enough. Sure hope it isn't a head gasket because I had that done with a new piston and cylinder less than 10k ago. I will find out more soon hopefully when I have free time. Cheers!

Dawggg,

Take a good look at your oil.
You wll get bubbles in the coolant if the waterpump seals are shot and the valve guide seals and guides are also shot.

Is your airbox dry or is it full of oil?
Is the engine oil turning milky?

Is there oil in the coolant?
bill

Hi Bill,

I've worked on quite a few bikes , cars, etc. Have a pretty fair working knowledge of how motors work but cannot figure out how bad valve guides/seals could continue to a bubbling radiator? Not questioning your knowledge just looking for some enlightenment.

Beek

Sent from my SCH-I535 using Tapatalk 2

Today I took off the carb from my 06 lc4A and saw something I had never noticed. Apparently there is s division in the middle of the intake to send separate currents od mixture to each admision valve. What bothers me is that the work doesn't seem as an original feature, it much more looks like a DIY version. Here is a picture of what you see when you look in the direction of the valves (valves appear as bright figures with a copper like color):


I also took down the left light, and noticed there is a spot where a bolt might go, but i am not sure if there should actually be something there. The left light actually has a threaded hole that matches the spot I signaled in red in the next picture:
,

Anyone has any opinions on these issues?

Split intake runner is normal.



... Maybe someone did some shad tree porting/polishing, though I've read that the porting and polishing from the factory looks poorly done.

My 2002 was exactly the same, the bolt was missing. I bought a second set of headlights on ebay and there is a vibration dampener there. This is the same dampener as the one used in the light support bracket.
I used to run the lights without this dampener and nothing weird happened, I have LED's now so :huh

D.

Thanks to both of you, I'll consider buying the dampener to give extra support for the lights.

"Looks" being the important word. There is no correlation between looks and flow. Some of the roughest porting generates great flow characteristics. Only the flow bench (or dyno) can tell you what is "beautiful".