Author Topic: What Do You Plug The Radiator's Smaller Tube With?  (Read 3488 times)

PilotSniper

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What Do You Plug The Radiator's Smaller Tube With?
« on: October 11, 2004, 05:31:18 PM »
The stock Keihin 32mm carburetor comes with a coolant path so that radiator coolant can flow through it in order to warm it up in cold conditions. The coolant flows from the smaller tube in the stock cylinder head, then through the carburetor's coolant path, then out to the smaller tube at the top of the radiator.

First, by eliminating the stock cylinder head and using and aftermarket one (K-fab Head), the smaller tube on the cylinder head is eliminated, so that takes care of one side of the equation.

Next, by eliminating the stock carburetor and replacing it with a Keihin PWK 39mm carburetor, the coolant path is eliminated altogether, so that takes care of the middle of the equation.

Finally, I'm left with the smaller tube at the top of the radiator. This smaller tube needs to be plugged so that I can complete the total elimination of this secondary coolant path.

My questions are as follows: What do you use to plug this smaller tube? Is there a rubber cap that can be clamped here? If so, where does one find this animal?

Thank you in advance for your time and efforts!
I started out with nothing and I still have most of it left!  :shock:

odykid

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What Do You Plug The Radiator's Smaller Tube With?
« Reply #1 on: October 11, 2004, 05:48:52 PM »
You got mail (AOHELL voice)....lol :D


Odykid :wink:

ludedude

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What Do You Plug The Radiator's Smaller Tube With?
« Reply #2 on: October 11, 2004, 06:03:43 PM »
I just used a clamp and a bolt that fit snugly in there. A shoulder bolt of the correct size would be even better sealing.

PilotSniper

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Solution!
« Reply #3 on: October 12, 2004, 03:48:43 PM »
Well, thank you for your input guys, but I concocted my own solution. It was easier than I thought, once I got the right items in hand. I doubled-up on two sizes of PCV valve caps (one fits nicely inside the other) and then used the OEM clamp to hold it on the radiator's small tube. It looks like it was made for this!!!

Case closed!  :)
I started out with nothing and I still have most of it left!  :shock:

Moskito

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What Do You Plug The Radiator's Smaller Tube With?
« Reply #4 on: October 12, 2004, 03:54:36 PM »
Go to Honda and get the little drain plug on the end of the clear tube that comes out of an XR50's air box.

Small brass (?) plug that's shaped like a shouldered bullet.  Cool little piece.

Partsfische lists it as:
17370-GCF-A20 PLUG, BREATHER TUBE -  A whopping $.99
Get the clamp that goes with it too:
95002-50000    CLIP, TUBE (C9) -  $.99 also.

I'm about 90% it fits - seems like it's what I used on the FS.
Moskito - Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming \'WOW-What a Ride!\'

PilotSniper

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What Do You Plug The Radiator's Smaller Tube With?
« Reply #5 on: October 12, 2004, 04:30:55 PM »
Skeeter, thank you for the tip! I'm going to stick with what I've done until such time that it fails (which I hope it doesn't). Either way, if the time ever come where I do need to replace what I've done, I'll get the information you've provided and run with it.

Thanks again for the tip!!!
I started out with nothing and I still have most of it left!  :shock:

Bucked

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What Do You Plug The Radiator's Smaller Tube With?
« Reply #6 on: October 14, 2004, 11:02:30 AM »
I suggest keeping the line intact. You can use new hose or get a brass union from the hardware store and connect the leftover segments. I think it is better to keep the amount of coolant transferred by that line flowing. It might look like an insignificant amount of volume but it could easily be 20% of the total coolant flowing from the head.

ludedude

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What Do You Plug The Radiator's Smaller Tube With?
« Reply #7 on: October 14, 2004, 05:00:48 PM »
The K-Fab heads (and others I've seen) do not have the spigot on the head for this line...so it needs to be removed. I had previoulsy blocked it off with my stock head and I've have not seen any ill effects in water temperatures....I monitor them with the Digatron gauge and do not remember any differences before or after this mod.

Moskito

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What Do You Plug The Radiator's Smaller Tube With?
« Reply #8 on: October 15, 2004, 09:30:24 AM »
Quote from: "Bucked"
I suggest keeping the line intact. You can use new hose or get a brass union from the hardware store and connect the leftover segments. I think it is better to keep the amount of coolant transferred by that line flowing. It might look like an insignificant amount of volume but it could easily be 20% of the total coolant flowing from the head.


Now how do you get a 20% number?  Inquiring minds wanna know.... :shock:

The whole idea of that pain in the arse setup is for carb heating in the winter - and to drive people that remove the stock stuff insane because it wants to piss all over your feet.  :D

Show me more than a couple (because I can't come up with any) examples of other carb heated rides (other than sleds, if they do it), if you will.

I wonder how common it is to do that?  The Pilot's the only setup like that that I know of.
Moskito - Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming \'WOW-What a Ride!\'

dhjunkie

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carb heating
« Reply #9 on: October 15, 2004, 04:47:28 PM »
I can come up with vehicle references for you :)
On cars the heated units are primarily there for deicing properties.  Generally they draw air with such velocity that it ices up the throttle body butterflies at the most inoportune time. WHOA Nelly!!!!!!!!

Bucked

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What Do You Plug The Radiator's Smaller Tube With?
« Reply #10 on: October 17, 2004, 06:07:09 AM »
Quote from: "Moskito"
Quote from: "Bucked"
I suggest keeping the line intact. You can use new hose or get a brass union from the hardware store and connect the leftover segments. I think it is better to keep the amount of coolant transferred by that line flowing. It might look like an insignificant amount of volume but it could easily be 20% of the total coolant flowing from the head.


Now how do you get a 20% number?  Inquiring minds wanna know.... :shock:

The whole idea of that pain in the arse setup is for carb heating in the winter - and to drive people that remove the stock stuff insane because it wants to piss all over your feet.  :D

Show me more than a couple (because I can't come up with any) examples of other carb heated rides (other than sleds, if they do it), if you will.

I wonder how common it is to do that?  The Pilot's the only setup like that that I know of.


Sniper said he was installing a PWK39 and I didn't know he had one of your heads. I was presuming the stock head was still in play. If I had one of those fabulous K-Fab heads I probably wouldn't have been thinking that way.  :wink:

 I wasn't suggesting anything about heating of the carb. I was just suggesting that with the stock head, connecting the smaller hose directly from the head to the radiator will help with coolant flow. The larger hose (16mm dia) has a cross sectional area of ~201.06mm. The smaller hose is ~6.5mm with a cross sectional area of ~33.18mm, which is a little over 16.5% of the main radiator hose and 14% of the total of both hoses together.

 My guess is that the heated carb was a lawyer inspired design intended to prevent icing in the throttle body that might cause the throttle to get stuck in an open position. Electrically heated carbs are common in aviation but the intent there is to prevent engine shutdown. That reminds me that I need to go fly some time soon.  :lol:

PilotSniper

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What Do You Plug The Radiator's Smaller Tube With?
« Reply #11 on: October 17, 2004, 08:25:16 AM »
Quote from: "Bucked"
Sniper said he was installing a PWK39 and I didn't know he had one of your heads. I was presuming the stock head was still in play. If I had one of those fabulous K-Fab heads I probably wouldn't have been thinking that way.  :wink:


Bucked, had I been running the OEM head as you assumed, I would have definitely taken your advice and kept the coolant flow going between the head and the radiator. Simple oversight. No harm done.

Thanks for all of the input guys!
I started out with nothing and I still have most of it left!  :shock:

Ramjet

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What Do You Plug The Radiator's Smaller Tube With?
« Reply #12 on: October 17, 2004, 03:08:54 PM »
Quote from: "Bucked"


 My guess is that the heated carb was a lawyer inspired design intended to prevent icing in the throttle body that might cause the throttle to get stuck in an open position. Electrically heated carbs are common in aviation but the intent there is to prevent engine shutdown. That reminds me that I need to go fly some time soon.  :lol:


Carb ice can form just about in any conditions. It plagues aircooled engines like the Lycomings I had in my plane. It can appear in summer but most of my experience has been in Spring when you have cold, moist air. It's not fun when you start to build ice and you drop in carb heat to remove it with heat from the exhaust. Your RPM's drop. If you're too late, you can make matters much worse and stave the engine of fuel.

For those not familiar with Carb ice. All it is is very fast air moving with moisture so fast on a metal surface that it forms ice. In an airplane, it can ruin your day.

The same is true of cars and trucks. Most throttle bodies are warmed from the coolant of the radiator. I never really thought about the Pilot and carb ice. Honda plumb it for a reason but I don't think the lawyers were involved.  Carb ice would just choke the engine and make you walk back to camp.  :?

Moskito

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What Do You Plug The Radiator's Smaller Tube With?
« Reply #13 on: October 17, 2004, 07:07:16 PM »
Quote from: "Ramjet"
Carb ice would just choke the engine and make you walk back to camp.  :?


I just hate it when I have to walk back to camp... :shock:

Can we use the ice in the carb to keep a brewski cold while we wait for help instead?

Wait!

Let's kill two birds with one stone:  Put the bottle directly in the intake air path and then use the air flow around the bottle to produce a cooling effect of the bottle's contents! :P   That would remove the coldness out of the air, thus acting like a carb heater.  Heat Osmosis?  Yea, yea, Heat Osmosis!

Okay, so I'm grabbing at straws...

May as well try to be at least a little constructive, eh?  :wink:

Anyone else seem to think I've been sitting in front of a CNC machine for too many hours now?   All I'm seeing is G-code!  It's taking over!!!  RUN!!!
Moskito - Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming \'WOW-What a Ride!\'

Ramjet

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What Do You Plug The Radiator's Smaller Tube With?
« Reply #14 on: October 17, 2004, 07:35:10 PM »
Quote from: "Moskito"
Quote from: "Ramjet"
Carb ice would just choke the engine and make you walk back to camp.  :?


I just hate it when I have to walk back to camp... :shock:

Can we use the ice in the carb to keep a brewski cold while we wait for help instead?

Wait!

Let's kill two birds with one stone:  Put the bottle directly in the intake air path and then use the air flow around the bottle to produce a cooling effect of the bottle's contents! :P   That would remove the coldness out of the air, thus acting like a carb heater.  Heat Osmosis?  Yea, yea, Heat Osmosis!

Okay, so I'm grabbing at straws...

May as well try to be at least a little constructive, eh?  :wink:

Anyone else seem to think I've been sitting in front of a CNC machine for too many hours now?   All I'm seeing is G-code!  It's taking over!!!  RUN!!!


I like your thinking!  Instead of poofkaboom, it would be kinkpfffftsss?  :wink: