This post is for any P650/700 owner who is interested in disconnecting their carb heater lines for cooler carbs and gas.

Check it out if interested. Click on My 650 photos then click on Carb Heaterhose Mod. I also did the airbox mod if anyone is interested in that also.

 

K.O.D. ... not trying to diminish your web site, but I have a differing opinion on the carb coolant lines...some one posted this here on CONNECTION, before... there was a guy on there, that used an infrared thermometer ( the kind you point the gun at something, & it tells you the temps... ) he found out that his carbs were actually hotter with the lines disconnected, than with them hooked up... I would suspect that most people assume that the coolant lines are for cold weather ( & I think I remember reading in the Kawi info, that it is to prevent carb icing ), but it appearently serves a few purposes... in K.O.D.'s situation, it may actually help, because he has wrapped his exhaust with header wrap, & we can all agree that the exhaust is a major component of adding heat under the quad... I think further study is needed, to determine if the carb temps are predominately the result of heat transfer ( heat directly transfered to the carbs, from the combustion chamber through the intake tubes, that bolt between the carb & the engine ), or weather it is radiated heat ( heat obsorbed by the carb, from sources like the exhaust, radiator, & outer engine cases )... if it is radiated heat, then the exhaust wrap will likely be the best way to cool the carbs, & IMO, only then, would it be even possible for the carbs to run cooler with the coolant lines disconnected... but we are likely to find, that even with the exhaust wrapped, that there is still too much heat obsorbed by the carb, probably both from transferance, & radiated heat, to benifit from disconnecting the coolant lines...

 

I have a Yamaha FZ1 motorcycle and a lot of guys do the coolant by pass too. I have read articiles saying you can ice your carbs at up to 80 degrees outside. On 2-wheels I dont want any surprises, so I wouldnt tinker with this. To make our bikes run cooler we use watter-wetter or somthing like that.

.02c

 

I guess its not for everyone. Im going to run mine like this and a lot of GNCC racers run like this also. One GNCC racer told me even the Kawi rep told him to do this as it wasnt needed in most conditions. I guess if I lived up north in Minnesota I wouldnt remove them. Down here in NC we rarely ever get temps below 20-25 and most of the time even if it is that cold its only for a day or two at the most.

 

The coolant lines allow the carb to remain at a constant temp. This helps ensure that the jetting remains good, regardless of the temperature of air entering the carb (within reason). Cold gas doesn't vaporize well, so it also helps in cold temps (aka freezing and below) to ensure the fuel will vaporize, versus puddle in the carbs.

Without the lines, in cold temps you'll need to jet up, and in hot temps, jet it back down. It'll give you a bunch more power for things like racing, but be prepared to jet before the run. For average riding at different temps, it'll never be jetted that great.

 

Wires, do you think I should hook them back up?

 

You will get more power with them off, but you will find that the carb will be more finicky with temperature changes. The idea is to pre-heat the incoming air (which loses HP), but basically keeps the incoming air at the same temp.

Changing it back is entirely up to you. I'd try it, and if you find that it causes issues during temperature swings, then change it back.

Where I ride it can be 40 degrees in the morning and then hit 90 by afternoon, so it would never work for me.

 

Well if thats the case in your area does other atvs that dont have the carb heater hose have problems? Why dont all atvs have carb heater hoses? Just curious?

 

Not sure. I thought all water cooled had them.

I'm not saying you'll have problems, it's just your jetting won't always be optimum, that's all. I had an '82 Pontiac Parisienne (big boat), with a slightly modified motor. In those cars, the air snorkel had a valve that regulated the intake air so that it either sucked over the exhaust manifold or cold air. I took it off, but then I had to jet everytime the weather changed, so I put it back.

It may be more to help the fuel evaporate before the engine fully warms up.

Like I said, run it, if you find that it's really rich when it's hot out, or running lean when cold, then put it back.

 

Well the P650/700 and V-Force have them "not sure about the BF" It probably does also. NO other atv water cooled or not, has carb coolant lines. I think it will run fine without them. It has so far but its only been 8 miles here in the yard. Many other people have done this a long time ago with no adverse effects Im aware of.

I think the cooler carbs with cooler gas will help promote more power "it cant hurt". Im sure the carbs will be cooler without the lines than with it. If coolant lines were needed for constant optimum jetting then nothing, water cooled or not, should run good Im thinking.

I forgot to ask about borrowing the Raytek temp gun today at work. Hopefully I wont forget tomorrow. I hope to collect data on this.