rmk800, if you can ride in several inches and maintain that 180-200 consistantly that is golden. regarding the bypass, on my yami with thermobob i installed a small 3/8 ball valve and ran it about half closed so not sure how that would relate to a drill hole. on my c3/ktm i run the bypass thru the bars. the c3 bypass thru the bars has ball valves as well and those push to connect lines are only about 3/16" id or smaller and they flow enough to get the bars hot. im surprised you dont have more temp swing with the bypass going full on thru the heat exchanger. your doing something right.
More tunnel cooler talk.
- Thread starter dooman92
- Start date
Thought I was doing good, but figured if there was room for improvement Id give it a shot. It will dip to 175 if I get into some really deep blower powder but always comes right back up to temp. Bike is plumbed as Selkirk recommends and it has performed flawlessly. I'll leave it be for the season. I do plan on ditching the rads next season and adding the C3 12" cooler to the tunnel, hopefully that will be a great combo.
Finally made some progress on my tunnel cooler on backup ride. Hopefully I attached photos properly. Tunnel cooler from summit cut down to 10x8". Had to make 3/4" aluminum tube tee bent at 90 to go behind frame from left to rt side of engine and connect expansion tank/ tube that fit in behind triple. Used some aluminum foil tape for heat reflection near exhaust and abrasion resistance at contact points.
blue hose looks Yamaha, I like that.
OK, you guys were correct. Exchanger size is just fine. I put the 190 stat in and covered the front of the head pipe and temps are perfect. The only thing I may need to do is uncover the engine in the late spring. About a quarter mile to the truck the road turned icy and I got over 200 easily. Air temp was about 32F and I was so close I didn't bother putting the ski scratcher down.
What is the OD on the spigots on your filler neck?
I am in the midst of changing over to tunnel cooler and deleting rads. Just wondering if I am going to need a reducer to 7/8" for the rest of my system.
I used 1" to 3/4" barbed brass reducers from amazon on my system.
pictures of my 580 arctic cat filler t that replaces my right / left side radiator, picture of hose size that fit bike and filler t.
Thanks ?
Like that aluminum guard you fabbed up there.
the material around the filler T is black race car plastic, once the radiator was gone my hoses seemed kind of vulnerable, so I cut and curved that piece, then my side covers over that are made of black truck tarp held on with bungee cords with ball ends, so far the best engine coverset up I've hand on my KTM.
I bought one of the cylindrical tranny coolers off ebay, modified the inlets and mounted it to my 300 aro. It seems to provide enough cooling with no radiators but I made the mistake of mounting it solid and the mounts broke after 3 rides. It is now secured with hose clamps. The bike doesn't get hot on long climbs in set up snow now, doesn't run cold in deep pow and I don't have to fool with radiator blockers.
I wish I would have switched to tunnel coolers years ago.
I wish I would have switched to tunnel coolers years ago.
Update : This tunnel is about twice too big for this application. As others have stated . In deep powder with no snow touching my engine I am running 155 F all other snow conditions it runs 162 F. Cooler is 16x8 so I will be cutting it to 8x8 soon. Want too see 185-200 in all snow conditions. Running a 194 thermostat does not help.
Assuming your thermostat is working you might just be revealing that you actually ARE getting snow on your motor.
(Backside is often the culprit)
An easy test is pinch a hose or add a valve to restrict flow through the cooler. (This is much easier than cutting and welding the cooler and potentially having the same results.)
I concur with sheetmetalfab, size of cooler ( too big ) will have no effect on engine temps. When the engine is sufficiently covered and protected from cold snow and wants to zoom right past 200 degrees, your 190 thermostat will start feeding cold coolant to the motor and maintain that 190 temp. Been there and been there. AS noted, until you cover the bottom and back of Ktm Or Yam, the system will not work. When you eliminate cold snow touching your aluminum engine, only then can the heat exchanger/thermostat take over and do its job. I can only vouch for KTM, but once running at 180 to 190 all day, clean oil, correct spark plug colors, no over fueling, can dump the hard starting yellow box program, didn't know my old slug had power until I completed the process several years ago.
It would seem to me that if you are running a 194 thermostat and your temps never even reached that, then you have not even engaged your tunnel cooler yet. Assuming your thermostat is working.
Thermostat has a bypass never really completely closed off. Should not dead head pump is what I have been told.
Ok but I will never stop all snow from getting in so I am trying to create a balance. Thank you for advice I do apreciate it and I am adding more snow blocking to my Selkirk kit.
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Yeah but the bypass, bypasses the tunnel cooler, correct?
Yes thank you for reminding me of that. I will be looking at Sealing my Selkirk kit up better.
I am not familiar with the Selkirk kit, but what I do know from tying to bomb proof our bikes and have them run reliably at 190 we have had to:
insulate bottom of the engine under the skid pan
built a flap to keep the track from throwing cold snow onto the back of the motor
covered the back of the motor
removed the radiators worked best for y ktm 500, one KTM riding partner still had his right side radiator but it is totally encased in closed cell foam and wrapped with silver aluminum tape
insulated the lines running to our coolant heated bars
cut down the bypass flow to just a dribble
run a felt like welding blanket cover over the top of our engines
Some shop fiddling for sure, but week by week as we added more engine protection our constant temps kept going up 10 or 15 degrees until we were always running 185 to 190. We run engine covers made of truck tarp, we have run silver closed cell foam directly on the motor and that worked ok too, we started with race car plastic and lots of stuffing foam in problem areas around the front of the bike, but it was too difficult to fit it tight enough to keep engine temps up. What we found though is attention to detail more important than material.
insulate bottom of the engine under the skid pan
built a flap to keep the track from throwing cold snow onto the back of the motor
covered the back of the motor
removed the radiators worked best for y ktm 500, one KTM riding partner still had his right side radiator but it is totally encased in closed cell foam and wrapped with silver aluminum tape
insulated the lines running to our coolant heated bars
cut down the bypass flow to just a dribble
run a felt like welding blanket cover over the top of our engines
Some shop fiddling for sure, but week by week as we added more engine protection our constant temps kept going up 10 or 15 degrees until we were always running 185 to 190. We run engine covers made of truck tarp, we have run silver closed cell foam directly on the motor and that worked ok too, we started with race car plastic and lots of stuffing foam in problem areas around the front of the bike, but it was too difficult to fit it tight enough to keep engine temps up. What we found though is attention to detail more important than material.
