Carb Heaters

[Cougar]

I have a stupid Qustion...

 

Why, for icing reasons do the carb heaters only turn

on at 68 degs? what would freeze at that temp?

-somthing to do with how cold fuel is?

 

And each one uses 15 watts to boot. I think I will disconect them. (60 total)

I could use them watts in other places.

 

The thermostat is calibrated to turn the heaters on at 68ºF and off at 78ºF. The purpose of the carb heaters is to eliminate the possibility of carb icing and to ensure proper performance under certain weather conditions.

[pegscraper]

No real answer, because you're right. That temperature is a little high. Several of us have unplugged them. My bike never had them to begin with. I've ridden in 20º temps many times and never had any trouble. They're just not real necessary. That 60W is much more useful elsewhere. Heated carbs or heated jacket for me? Hmmm. That's a toughie.

[boominup]

Carb heaters would be fine if I was cruising 15000 ft in the air and it said CESSNA on the side of my ride! Brian

[gunboat]

i have unpluged mine a year ago. see no reason for them down south texas. i use the extra watts to run my grip heaters when i need too, and thats not very often.

just my 2-cents

don c.

[Cougar]

Well, Heck I live in Iowa. and it gets down below -30 degs..

(Bike stays in garage until March)

 

I am not riding anyways. I ride when the weather is nice

out.. I am just not understanding this yet.. I guess they would

be fine if you road all the time when the temp was 30 degs out.

 

Nope not for me!

 

BUT the heaters still would not kick in yet.. SILLY TO ME!

Heck that is 60 watts for my extra lights on front.

[ToRide1]

I have not tried this my self! Its said there is a wire that runs up under the seat on the left hand side that go's to the carb heaters and some where just under the seat & tank there is a quick disconnect in the wire! You can instal a switch and mount it to the frame under the seat and all you would need is a switch, wire and some crimp on connectors to mach the connectors thats already there.

[Cougar]

Yep there is a connection under the tank just above the front

left of the carbs. (it will be the white connector)

[ATTACH]26918[/ATTACH]

OR

you can go on the right side of the bike

behind the cover and disconnect one of the

gray wires (tape it up when you do that) that

goes to the sensor.

Jeff

[jlh3rd]

it's not necessarily the outside air temp that causes carb ice...it's what happens to the air temp with the associated moisture as it travels through the venturi of the carb......this venturi effect can rapidly lower the the air temp, and since warmer air holds more moisture....this can freeze..............carb ice is more common in aircraft with relatively warmer air temps than cold........an air temp of , lets say, 20 degrees F has less moisture than 50, 60 degrees..........so the 60 degree air has a better chance of causing carb ice...............this is from my private pilot days......

[Cougar]

I also remember from my private pilot days that our aircraft fuel

was running at about 140 Octane as well, If my memory serves

me right.

 

I did think if that but with ALL the engine heat in

such a tiny area.. I still think they will never ice.

[jlh3rd]

you wouldn't think so......................how does 140 octane fuel figure into carb ice or no carb ice....and my a/c used 100 low lead

[OutKast]

I thought it would be good to have them switched to use just while warming the bike up. But I saw a post from V7goose the other day in which he stated the carb heaters are also only powered when the bike is in gear, not during a nuetral warmup. Guess I need to check a wiring schematic and verify he is right.

[V7Goose]

I thought it would be good to have them switched to use just while warming the bike up. But I saw a post from V7goose the other day in which he stated the carb heaters are also only powered when the bike is in gear, not during a nuetral warmup. Guess I need to check a wiring schematic and verify he is right.

I'm right, but you won't tell that from the schematic. I originally thought it ONLY came on in neutral, but another member set me straight. The only way you are gonna figure out the truth is to manually test the circuit. Not looking at the schematic right now, so hope my memory serves: The problem is that Yamahaha's stupid schematic does NOT tell you that the activation relay is a normally-closed relay instead of the more common normally-open. So the ground through the neutral switch OPENS the relay and shuts them off.

Goose

[KiteSquid]

For a good, quick, down and dirty definition on Carburetor Icing, read the article a Wikipedia HERE

 

Then click on the chart at the end of the article, and UNDERSAND that the chart is in degrees C, NOT F. 30C = 85F 20C = 68F

 

It is quite an eyeopener.

 

 

I will not be disconnecting my carburetor heaters as the Yamaha engineers did a good thing (But they could have added a dew point sensor)

[Squeeze]

I for one never ever heard of Carbs on V4 Motor being iced up.

 

I don't know why they put these Heater in the RSV, but the new VMAX hasn't Heater either. Probably it's because of the smaller 32mm Carbs producing a faster Airflow in the Venturi. If i had them on my Bike, i'd disconnect them the next Time i'm near the Connector. Makes no Sense.

[KiteSquid]

Side note: Carburetor icing is not as detrimental on an on-road vehicle compared to an aircraft.

 

We can pull over to the side of the road......they cant.

[SaltyDawg]

You can just pull the fuse for them. It's located in the lower right faring. Much easier than pulling the tank and disconnecting connectors.

[N3FOL]

For a good, quick, down and dirty definition on Carburetor Icing, read the article a Wikipedia HERE

 

Then click on the chart at the end of the article, and UNDERSAND that the chart is in degrees C, NOT F. 30C = 85F 20C = 68F

 

It is quite an eyeopener.

 

 

I will not be disconnecting my carburetor heaters as the Yamaha engineers did a good thing (But they could have added a dew point sensor)

 

 

I just had a feeling that there is a good reason why Yamaha designed to have the Carbs heated. My carbs will remain in tact and not disconnecting anything in there.

[pegscraper]

The factory must have had a good reason, eh? That's crummy logic for doing anything. That's putting way too much faith in Yamaha's decisions. Do you really believe that they never make any mistakes, they never do anything they shouldn't have done, or don't do something they should have done? I think we all know better than that.

[Squeeze]

The factory must have had a good reason, eh? That's crummy logic for doing anything. That's putting way too much faith in Yamaha's decisions. Do you really believe that they never make any mistakes, they never do anything they shouldn't have done, or don't do something they should have done? I think we all know better than that.

 

I second that.

 

There are so much Things which shouldn't happen or shouldn't have been designed the Way they are. Someone was afraid by the small Carb Diameter and made the Decision to bring the Heater in. Maybe it was Mikuni, when they designed the Carbs and found icing on one Occasion under specific Circumstances. They reported to Yamaha and somebody said, "Let's don't take any Chances here. We have a solid Reputaion to defend, that's why we stick to Cassette Deck. Icing of the Carbs shouldn't happen at all. Lets go with Heaters". Mikuni sure is happy when they can sell something extra.

[SaltyDawg]

No disrespect intended to anyone but I personally wouldn't use a service that allows "anybody" to edit it's content as a true source of information.

 

How many motorcycles have carb heaters? Has carb icing become such a problem that we need to worry about it?

 

The carb heaters are an un-needed power drain on the bike and are in fact "ON" when the temps drop below 63 regardless of whether the bike is in gear/motion or whatever. I have had a digital voltage meter on my bike through the winter and have seen the drain on the system while riding down the road. With the sorry amount of available power that these RSV's have I'm willing to take my chances to get the 5 amps back that these things are eating up. That allows me to have my electric gloves, socks, and grip warmers and not put an unnecessary drain on the charging system.

 

For the life of me I can't think of what Yamaha was thinking. I'm sure their target market for the RSV was not people like me who ride in everything except snow regardless of the temp.

[SteveW]

Hi Wayne

Is the carb heater fuse labled ?

I need to pull mine with the hack and extra lights I don't need the drain.

 

Thanks Steve

[SaltyDawg]

Yeah Steve it's marked on the inside of the fuse box cover. It's under the right lower faring. It's also in the maint book if you have one.

[V7Goose]

The fact is, the carb heaters are ONLY powered when the bike is NOT in neutral. The carb heater relay is normally closed, which connects power to the carb heater thermal switch any time it does NOT receive a ground from the neutral switch. When the bike is in neutral, the carb heater relay is activated, which shuts OFF the heaters.

 

The second fact is that the carb heater thermal switch turns ON (supplying power to the heaters) when the temperature drops to 20C (68F). At this point,the carb heater thermal switch remains ON until the ambient temperature behind the right battery cover reaches 26C (79F). I do not know what the thermal switch does if the bike is turned off when it has been switched on, but the outside temperature is still between 68 and 78. I suspect that when the bike is started again it will remain on, but I won't yet call this a fact.

 

The third fact is that I believe the easiest way to permanently disable the carb heaters is to simply unplug one of the leads to the thermal switch under the right side battery cover, or to unplug the carb heater relay in the same location. It is easier to pull the battery cover than the right lower fairing. If you want the option to just disable the carb heaters on demand when you need the extra juice (possibly if your battery is getting weak or you decide to plug in that heated snow suit), just install the cutout switch I describe in the tech library.

Goose

[OutKast]

Could I plug into the disconnected connector under the tank and power something else? Is 5 amps enough for a heated grips? Or passing lamps?

 

Or enough for an additional power outlet at the rear seat? Or is there already a connector for that?

[Guest retusn]

I will be putting new needle valves in my carbs this week and will have the tank off and obviously will have the connections already disconnected. Can I safely assume that living here in southern Nevada that leaving the plug disconnected will not be harmfull?