Manufactured heat exchanger kit (Full radiator delete) for sale

[Chadx]

Sounds like this is the thread to be on. I'd worked through a bit of this on the thread https://www.snowest.com/forum/threads/yeti-tunnel-cooler.454418/page-2 and so reached out to Dave/XRT. He whipped up a coolant bottle for me with the site and angle fittings and neck angle I wanted. Received the bottle last week and will soon tackle my coolant system revamp.

Backstory: End of 2019, I built my third snowbike since 2013. This build was a 2020 YZ450F and 2020 Yeti 129. I wanted to do a tunnel cooler on the build which is part of what had me trying a Yeti (previous two rigs were KTM/Timbersled, Husaberg 501/CMX 129). When the 2020 Yeti hit the ground, everyone said the C3 tunnel coolers would no longer work due to the new aluminum bracing on the Yeti so I did the build without a tunnelcooler. Then, many people were successful installing the C3 tunnel cooler and simply drilled through the extra aluminum with no issue. Fast forward through 3 season; each of which had me, on certain points on nearly every ride, wishing for a tunnel cooler. This is the year. I ordered the tunnel cooler and associated parts this fall and started evaluating coolant bottle solutions so I could decide if I was going to do a radiator delete. In the other thread (linked above), Dr.Z mentioned the XRT solution. A few emails later and my custom coolant bottle was in the mail.

I run a Selkirk engine shroud and have a bib that I made to cover and uncover the radiators (it covers everything from the Selkirk engine cover all the way up and wraps back towards the intake cover (think gas tank on Non-Yamaha bikes); so full coverage. It really is like a bib that goes around my bikes "neck" so does a really good job blocking all snow/cold including any that would enter from the top. Foam insert between the frame rails under the motor held in by Selkirk skidplate. Same foam around rear if engine. I have the Selkirk heat exchanger plumped on the thermostat-open circuit. (Selkirk always recommended it go on the bypass circuit, but only wanted it on the thermostat-open circuit). This setup works quite well, though I do still have to put the radiator bib off and on; Off for the trail ride in and then on (most of the time) when we reach the pow. Selkirk heat exchange and coolant-heated bars are plenty most of the time with occasionally needing to uncover the top part of the radiators depending on snow conditions. Running a C3 90C/194F thermostat, C3 intake, etc. Main issues with getting hot is when doing long, WOT but slow over-the-ground speed, uphill pulls in deep pow. Also in spring snow when riding slow (not enough air over the uncovered radiators). I also ran Evans waterless coolant last season and found that I now prefer it over typical coolant as I don't boil over if temps get away from me on a long pull. I'll run it again in the revamped system.

For this cooling system revamp, I'll pull out the Selkirk heat exchanger and related plumbing, but keep the Selkirk engine surround which I love. I am removing the Bulletproof brand radiator guards and replacing with Unabiker since they will better support the XRT coolant bottle and the bikes plastic shrouds. C3 sold me a smaller diameter thermostat nipple for my existing C3 thermostat. The stock Yamaha hose is a very large diameter that feeds the radiators. The tunnel cooler lines are 5/8". This smaller thermostat nipple will let me stretch a 5/8" silicone coolant hose over it, run directly back to the tunnel cooler, then forward to XRT coolant bottle which will be mounted to the Unabiker radiator guards (with no radiators). Dave put a 5/8" coolant bottle return line nipple and angled it back 45degrees for me. So 5/8" tunnel cooler return line goes in the side of coolant bottle then 5/8" out the bottom of the coolant bottle and into one leg of my stock Y collector going into the water pump. I currently have a C3 hose on the other leg of that Y collector that combines a line from the left radiator and heated handlebars. C3 sold me a new fitting to replace that; a simple stubbed silicone hose with only one adapter on it; for the C3 handlebars inlet.

So in short, my thermostat bypass circuit will come off the thermostat, through the heated bars, into one leg of the waterpump Y collector. The thermostat-open leg will come out of thermostat, back to tunnel cooler, forward to the XRT coolant bottle, then down to the other leg of the waterpump Y collector. Will really clean things up compared to the current Selkirk heat exchanger, heated bar, and radiator setup. I plan to run the bib fulltime now, but will have the option to remove it if I ever get into a situation (boiler plate trail on the way in in the spring) where tunnel cooler isn't getting enough snowdust. Removing the bib will let air hit not only the coolant bottle, but all that air will push into the engine bay and out the side. Not like having radiators, but will be at least an option to get a tiny bit more cooling in those rare trail situations where the tunnel cooler will struggle. I'll be thinking through a scratcher solution as well (rails? Or more likely, on the rear pf the ski).

Build pictures to come in the next few weeks (in this or a separate thread).

 

[AllHatNoCattle]

Chadx: Thanks for the write up. I just installed most of the XRT cooler on my motor, and I used the diagrams on the XRT website.

He recommends using the coolant bottle different than what you are suggesting. Here is how he suggests it goes:

Hot Coolant output > Thermostat > Thermostat Bypass > Heated Bars > Coolant Bottle > Cold Coolant into Motor

Then on a separate loop:
Hot Coolant output > Thermostat > Exchanger > Cold Coolant into Motor

What are your thoughts on this? Just wondering why you are doing it differently.

Here are some pictures of my bike as it sits right now. I am waiting for a new kit to show up, so I have only done the motor part so far (and haven't fully completed it with a hose clamps and coolant catch bottle). So it is not complete, but the pictures might be worth discussing.

 

[Chadx]

Chadx:
He recommends using the coolant bottle different than what you are suggesting.
...
What are your thoughts on this? Just wondering why you are doing it differently.

I was aware that Dave recommends doing only the tunnel cooler on the thermostat-open circuit and recommends his coolant bottle on the handlebar/bypass circuit. In my opinion, it really doesn't matter and so for me, I'm plumbing the coolant bottle into the thermostat-open circuit and keeping the bypass circuit dedicated to the handlebar circuit. A large part of that is just that layout of the plumbing working better for a YZ450F with the wrap around header pipe. I'm going back to the tunnel cooler and then, as I route the return forward from that, can to up into the coolant bottle inlet, then out the bottom of the coolant bottle down to the waterpump collector. That keeps me from having to loop and secure the return up and around the exhaust and then down to the collector; routing to the coolant bottle first makes that routing naturally. This also keeps me from having to shorten/trim/reroute my existing handlebar coolant return line which current runs all the way down to the waterpump collector. I'd need to shorten/reroute it up into the side of the coolant bottle if I plumbed like that. Either way, I'm not concerned about cooling because the 30" tunnel cooler I'm using on my Yeti has a good history of more than adequate cooling so I don't think there is an advantage to either routing for my particular bike and tunnel cooler. C3 says the 12" cooler works for 98% of riders so the 30" will surely suffice (I chose the 30" simply because it mounts easier and is overkill for those boiler plate, spring trails and because I was doing a radiator delete and have no backup cooling in those situations).

So long story short, I think routing either way will work equally well for my setup (and for most people) and so whichever routing works best for a persons bike and snowbike kit setup is the way to go.

I started on my install Sunday. Only worked on it a few hours. Removed the kit from the bike, drilled the tunnel cooler holes, but then got sidetracked into removing both shock assemblies and pulling everything apart to lube. Also pulled apart and re-greased the Yeti assembly for tightening the chain. And, I'm taking pictures of everything which slows me down. I'll end up starting a new thread with all that detail since the Yeti tunnel cooler, etc. is unrelated to this thread, but I'll at least post the coolant bottle mount in this thread when I get there. Might be a week or two before I get to that. No rush to get this done as we are over a month away from adequate snow and I have a long list of other chores to get done before then.

 

[mumur]

I'll buy a CMX one once you have it up on the site.

 

[Chadx]

I finished installing the tunnel cooler, put the kit back on the bike then removed the radiators, Selkirk heat exchanger and all related plumbing, and removed old radiator guards. I temporarily installed the unabiker radiator guards and that is where I left off. Waiting on some plumbing parts/adapters to arrive before I do the final phase (replace C3 thermostat nipple with smaller size, attach XRT coolant bottle to Unabiker radiator guards, hook up final plumbing, and refill with Evans waterless).

 

[AllHatNoCattle]

My install is complete. Now to test it out....

 

[XRTEngineered]

My install is complete. Now to test it out....

Very clean install!! Hats off to you!

Only thing Im concerned about is the hoses from heat exchanger going up past your exhaust, that seems like a long span of hoses that are not supported. Those hoses will be bouncing and flying around alot if left like that! potentially ripping out of a connection or fraying at a connection or elsewhere.

 

[XRTEngineered]

I'll buy a CMX one once you have it up on the site.

Working on it!

 

[AllHatNoCattle]

Very clean install!! Hats off to you!

Only thing Im concerned about is the hoses from heat exchanger going up past your exhaust, that seems like a long span of hoses that are not supported. Those hoses will be bouncing and flying around alot if left like that! potentially ripping out of a connection or fraying at a connection or elsewhere.

Fair point - I really was not sure the best way to route the hoses through that section. My concern was that with the TSS the track would be moving around a lot and if I pulled the hoses down to the skid and secured them then with each movement they would push the lines up into the engine area or something, Creating friction points.

I have the lines secured just behind the shock mount (see below picture) and then they are tied together with zip ties along the span to the connections. I also cut the lines the right length that this is where they naturally want to sit without the zipties holding them together.

Do you think I should come up with some sort of support in the middle of the span?

 

[XRTEngineered]

If it was my bike with a TSS, I would have ran the lines along the skid frame rails to the swing arm mount which is the pivot point and zip tie it there. That pivot point has the least amount of movement and wont be an issue at all, your hoses will be secured to the frame rails, and from there you can send it any way you like. If you want to keep the routing how it is around the engine, then a few 90° elbows to send it up and forward.

 

[XRTEngineered]

Its hard to say if you need to add in a support as is, I dont know how stiff it is with the hoses you are using.

 

[Chadx]

I finished plumbing my C3 tunnel cooler, radiator delete and XRT coolant bottle yesterday on my 2020 YZ450F/2020 Yeti 129. Filled it up and circulated to test everything. Works great. Very happy. As mentioned, I plumbed mine with bypass circuit routed only through heated handlebars (not coolant bottle) and then to waterpump Y collector because that was easier routing for my application. I plumbed the thermostat-open circuit back to tunnel cooler, via a 180degree bend silicon hose, through the tunnel cooler, back forward and up to the XRT coolant bottle, then straight down to the other leg of the waterpump Y collector. XRT coolant bottle is mounted to Unabiker radiator guard. I love the Selkirk engine surround and will keep that (minus the selkirk heat exchanger). I'll typically run with entire front of bike covered with my radiator bib that wraps from top of the Selkirk all the way up around the top of the (former) radiators and meets behind the bar mounts (over Yamaha airbox) which give complete coverage, but I'll be able to remove the bib if I ever get into the rare trail situation where the tunnel cooler isn't cooling enough. This will push air across coolant bottle and push air across the engine/header.

I'll do a separate thread for the entire build once I'm done. I run Evans waterless and so my leak test was done with some leftover evans prep fluid I had. Next work will be draining and refilling with Evans waterless and then adding coolant hose protection, securing hoses, piecing back together the shrouds and Selkirk engine surround.

---------------------------

XRT bottle bolted to Unabiker radiator guard.




I had the XRT neck welded straight up rather than angled. Also had the inlet nipple upsized to 5/8" and angled 45 degrees since I was using it on the thermostat-open circuit.





Used 5 bolts. Top two I went through both first and second coolant bottle tabs and used loctited nuts against inside and outside.



Test fits showed the potential for some rub areas. I dremeled and sanded all the sharp corners on the XRT coolant bottle. I also had some grey trim molding from another project and fitted that to many places on the Unabiker radiator guard and coolant bottle (this shows only one section. I did several more).





Bottle from the front of bike.





Bottle from rear of bike. Still have to finalize hose protection and secure them, but this was a successful heat cycle and leak test.
You can see one of the additional pieces of trim added to the outside edge of the unabiker guard to cover that edge.

 

[CB_Rob]

My install is complete. Now to test it out....


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Will it matter that the left side cold water return will have much cooler water than the return on the right side that is just going through the bottle?
Do the both of the two cold inlets need to be flowing?

 

[AllHatNoCattle]

Will it matter that the left side cold water return will have much cooler water than the return on the right side that is just going through the bottle?
Do the both of the two cold inlets need to be flowing?

I dont think so. Inside the motor they are blending together anyhow.

 

[AllHatNoCattle]

Quick update, I had one ride on this setup, which isn't enough to form a full opinion yet, but I do have some first impressions:

1. Rode with early season conditions (less than a meter of base), but it had about 2-3 feet of powder on top. Cold temps (-15celcius, 5 degrees Fahrenheit)
2. Noticed that the bike takes a lot longer to warm up when just sitting. This makes sense since there is so much more hose I guess
3. Temps were very consistent in the snow. In the blower it was 130-150f pretty much the whole day.
4. Up the trail the temps would get 180-190 and I would pop off into the sides and it would cool down quickly
5. Going down the trail at the end of the day I forgot I had a heat exchanger and didn't look at the temps. Noticed my clutch felt funny and looked at the temps: 222f...!!! It is very important to remember that you have a heat exchanger, as I am used to just bombing down the trail at the end of the day without thinking about temps or hitting the snow on the sides.
6. I might try to seal my motor better - too much snow gets in the top and creates steam and ice. It was really deep snow though, so I will try a few more rides before I do anything.
7. My bottle still holds enough heat on the radiator guard to create ice. If you are doing a build you may want to give more space between the bottle and the radiator guard to prevent this
8. I still had ice around the bottom of the motor, but not near as much
9. Now I had ice on my tunnel, near the heat exchanger. So I am not convinced that I am saving much in ice weight (one the main things that attracted me to the heat exchanger)


Once I have some more rides, I will report back if anything else jumps out at me.

 

[Dr._Z]

You need to cover the engine better for sure. Yesterday, mine kept above 170 in the powder all day, even with the heated bars on full.

 

[00Tundra]

Secret is to seal front and back of engine. This will keep more even temp. My YZ with modded selkirk kit ,heat exchanger with no radiators never drops below 160.

 

[AllHatNoCattle]

Secret is to seal front and back of engine. This will keep more even temp. My YZ with modded selkirk kit ,heat exchanger with no radiators never drops below 160.

I've got the front, sides and back pretty well sealed (some small holes do exist). My problem was snow coming over the top of the radiator guards and falling down into the motor area. I think anyways...

 

[Chadx]

I've got the front, sides and back pretty well sealed (some small holes do exist). My problem was snow coming over the top of the radiator guards and falling down into the motor area. I think anyways...

You probably remember it from the thread we were on a couple years ago, but for a refresher, see my post here https://www.snowest.com/forum/threads/selkirk-engine-armor.452323/page-2#post-4341728 regarding the material and layout I use for a big radiator bib. Since then, for even more coverage, I updated it so the ears run all the way back over the electrical connections and gap in the shrouds. Added two grommets on the ears and they meet on the back side (rider'side) of the forks. Just like a person wearing a bib that ties behind the neck. Even on blower powder days, it keeps the snow out along with the selkirk surround, and gym mat foam that I have under the engine and behind the engine (there are pics and descriptions of that some where in that same thread).

 

[dooman92]

Allhatnocattle, good looking setup. FWIW, I had better luck with heat exchanger and no rads on a fx conversion primarily because with only one inlet for coolant (cold return) to the engine I could eliminate uncontrolled heat exchange from convection that is more difficult with the two inlet ktm. That hose from your aluminum bottle to the engine case allows for unregulated convection with will allow the warm coolant to rise and cooled coolant to fall in that hose and make the aluminum bottle work effectively as a radiator. No coolant flow is necessary. If that bottle is cold it will cool the engine, if the engine is warmer it will transfer heat to the coolant in the bottle and warm the aluminum which makes a good radiator. probably adds a bit to warmup times as it acts like a radiator. It stays warm and melts snow because of the convection effect. Insulating shielding the bottle from snow will help. I attemped to make an aluminum pipe with a trap to stop convection on that line on my attempted ktm conversion. Just not enough room and gave up. On my fx conversion, I teed the bottom bottle hose into the return line from the exchanger it worked great with consistent temps. But, same deal, watch temps on icy or low snow trail.

Appreciate the photos, makes me think about tackling that ktm again. On one of my ktms I installed a two thermostat system from C-3 with stock radiators which works better than stock but still suffers a bit from convection on that same hose as yours. Good luck.