KTM thermostat ?'s

[jmics19067]

Dear KTM riders,

I am hoping someone could help me out here. I am finishing up a project bike and I was curious about setting it up with a thermostat. I have heard some KTM's came with them and I was wondering if you thought they where worth it. Here are my questions.

How are they set up ? are they inline on the radiator hoses? If they are inline on the hose are they 3/4 " lines? Do they regulate all the coolant coming out of the head with a bypass hose to the water pump or do they just shut off one radiator? About how big are they for mounting space and ball park on what they would cost. Has anybody experienced any issues with them?

A picture would be worth a thousand words on how they look and are piped and any comments would be greatly appreciated. Please help me decide if it is a waste or a good idea

thanks
Jim

 

[MrLuckey]

If you dont get all your questions by tonight I can take some good pics for you after work. I have my radiators laying on the bench so I can get some good ones for you.

 

[jmics19067]

:worship: :thumb:

 

[KDXfile]

I think if you ride in cold weather, it would be a good idea. I noticed last winter when it got down in the 20's my bike warmed up good and ran fine so the system works well. From looking at the setup, it shuts off flow to the right side radiator. Also the right radiator has 3 pipes and the left has 2.

 

[biglou]

I posted a hand-drawn diagram of the setup on my MXC a while back for someone else. It looks like the thermostat only shuts off flow to the right radiator on my bike. Could be different on others, I'm not sure.

 

[jmics19067]

Yes I do remember this topic some time ago but I couldn't find in a search.
Probably lookin in the wrong place but.....

I have converted some straight KTM rads to fit my bike< larger core area plus a lot stronger looking than my stock twisted up/leaking Japanese rads>. I had to rearrange the ports a bit to get them to fit my bike< large fuel tank and expansion pipe crash clearances>.

The setup I have is out of the head<3/4> to a Y pipe to the top of both rads<5/8>. The bottom left rad transfers to the right bottom<5/8>. At the very bottom right a large port straight down to the water pump<7/8?>.

Had to close off the bypass<?> port and add a large draw port on the ktm right bottom .

So now I have larger ports on the returns and transfer hoses<3/4" KTM compared to 5/8" Japanese> with a 7/8" draw port<water pump inlet size>. Actual hose size is only a guesstimate by sliding on 5/8 3/4 and 1 " heater hose. I am just taking a wild guess that pump cavitation will not be an issue with intended use because of the help of the larger ports if I close off 1 rad. I am now curious, if the KTM thermostat inline a 3/4" hose. And its physical outside dimensions.

1/2 of my questions are basicly answered< closes off 1 rad>. Now I just need to figure out if it feasible due to space limitations and lack of bypass hose. Thank you ! :worship:

 

[MrLuckey]

Link to pic of radiators: http://home.earthlink.net/~drnspode/images/RADIATORS002.jpg

The top hose of each radiator appears to go above the thermostat and are open all the time.

If sitting on the bike, left radiator bottom connection goes to bottom of water pump where I presume is the infeed of the water pump.

Out of the top of the water pump housing is the hose going to the bottom left of the thermostat. (Open only to the smaller 1/2" hose to the bottom left side of the right radiator when cold).

All three ports of right radiator are free flowing in all directions.

Bottom of right radiator is connected to right side of engine. (opposite side as waterpump).

All hoses are 3/4" except the bottom right output of thermostat housing to bottom left of right side of radiator) 1/2"

Dang, I hope that all makes sense....

From what Lou and I have discussed, his 250 and my 400 are very different in the way they are piped......

 

[jmics19067]

Mr. Luckey, Big Lou,

does it sound like that the hot water coming out of the right side engine goes into the bottom of the right rad ,thru the hoses on the top, to the left rad back down to the water pump. With the small diameter hose short circuiting the water past the radiators back to the water pump when the thermostat is cold? Are you not truly shutting off 1 radiator but only allowing some water to bypass the radiators

Is the water temp on the top<2 hoses on the top of the rads> what signals the thermostat to bypass or not <opening closing the 1/2 " hose>?

dang I wish I had a KTM dealer nearby , sorry if I am being a pain in the butt with my questions

Thanks again
Jim

 

[MrLuckey]

Looking at my 02 400SX setup more closely, it definitely cuts off flow to both radiators until the thremostat opens. Lou's 2-stroke setup is definitely mucho different.

Water flows into the bottom portion of the thermostat (3/4"), while the thermostat is closed it flows out the 1/2" connection to the bottom of right radiator where it goes out the bottom 3/4" to the cylinder, head waterpump and back to the thermostat.

Once the thermostat opens, water goes up to the top of both radiators, flows down through them and then back to the waterpump.

 

[jmics19067]

ahhh now that makes sense to me . great thank you!!!!!!!!! :worship:

 

[old#48]

jmics19067, if you want, send me an email and I will send you a pic of a thermostat in place on a '00 300 exc. [email protected]

 

[jmics19067]

I think I have an idea on what it can and I can't do. space was more than a problem than I previously expected . Going from the 5/8 hose to the 3/4 actually warranted having to use a metal tube to replace most of the rubber hose for clearances<smaller outside diameter> to prevent possible chafing problems. Unless I rerouted the hoses so I couldn't take out the spark plug.

Thanks anyway though but I am going to set the thermostat idea on the back burner for now. I am going to wait to see if what I have done so far is going to cause any problems before I make a new set :eek: