Heating up and idle problem?

[bagherra]

Hi all,
I've read some of the threads regarding hot Vmaxs. I'm looking into doing the fan switch mod. I just took it out tonight and in stop-go traffic it got up to about 3/4 - higher than 1/2, but not yet getting red. My overflow tank cap needs to be replaced (it's cracked) so I wonder if that may be part of the problem. I replaced the old coolant with Engine Ice over the winter. I completely flushed it so I know the coolant is fresh.

Since it wasn't hitting red yet, the heat didn't concern me as much as the idle. As it heated up the idle got below 1000 and the bike stalled twice. It started right up, but I wonder if I need to tweak the carbs somewhat for the warmer weather. It runs great once I'm out of traffic.

What do you guys think? :ummm:

 

[vmaxcruzer]

I would check for air leaks around the carbs first. Probably wouldn't hurt to go through them with a good cleaning if its been awhile. If you've never been into them then just seeing what jets are there could help diagnose problems. Definitely need an over flow tank, if it belches out this summer your balls will pay the price. Good coolant, properly operating components like the thermostat and fan are all you need. A fan over ride switch is a good idea to combat early heat rise in traffic and its simple to install with little money and time.

 

[Rhoy Carter]

Check your charging system. My 85 would do the same thing when it heated up and it turned out that at idle when hot it was not charging like it should. Low voltage will cause your problem. Some people are using the r-1 R R and the late modle with the ground wire works fine for me.

 

[bagherra]

Thanks guys. I'll replace the cap for sure. Hot coolant won't be good for my balls. The carbs were cleaned when I changed the jets with Sean's jet kit. I should have mentioned they were jetted. They're using the 157.5s.

Everything is good until it heats up. No problems at all until it went beyond 1/2. It was perfect this Winter...I rode it in the 20s,30s,40s, and it rode great.

I'll check the charging system. What do you mean by R R? Sorry for the newbness.

 

[Jdk203]

I want to do add a fan switch myself but I've tried searching for a how to guide on it and came up empty handed. Is there one somewhere or is everyone using a kit to do the mod?

 

[Jdk203]

Got to thinking about it and I answered my own question.Should just need to wire a switched jumper in across the sensor and should work fine for over riding the sensor. Guess Ill do that.

 

[Rhoy Carter]

Under the right scoop the 2 wire sender on the coolant (jump these 2 wires with the switch

 

[gamorg02]

jdk, basically splice the two wires coming out of the thermostat together with a switch inline.

 

[Rhoy Carter]

R R = regulator / rectifier

 

[RaWarrior]

I dunno if there are "kits" for the fan switch. You just wire the aux switch in parallel with the thermostat's switch. That way either one can kick the fan on.

There's wiring diagrams in the service manual, which is on Vmaxoutlaw for free. I'm sure somebody here knows exactly which wires to do it with.

I dunno about the Vmax, but on my Yamaha snowmobile the thermostat turns "on" by completing a circuit to ground. That whole sled is kinda backwards....switches are on the ground side rather than hot, so are the fuses.

I think the aluminum fan helps too, though some people don't. With the aluminum fan blade and fan switch, my temperature has never risen above half way up the gauge, ever. The fan is a bit slower with the metal blade, so it definitely seems like it's moving more air. It certainly can't hurt.

I also don't really subscribe to the "engine ice" stuff. To improve the cooling ability of the liquid in your system, you'd want it to have the lowest specific heat possible. The higher the specific heat, the longer it takes to absorb and release heat, or more specifically how much energy can be absorbed without changing temperature. The faster the liquid can release heat, the more effective your radiator is. Water is rated at 1. A 50/50 mix of water/ethylene glycol coolant is rated at about 0.81, whereas 100% eth. glycol is rated at .59.

Now for the kicker: if you go to the official Engine Ice website, they publish that their product has a specific heat of .92---significantly worse than the typical 50/50 green stuff. Their base is proplyne glycol, aka the environmentally friendly stuff. Like all "green" stuff, it doesn't work as well, a 50/50 mix of that is rated at .85. So somehow Engine Ice made it worse as a coolant with all their "miracle" additives, probably to raise it's boiling point. The 50/50 stock they start with boils at 222, considerably lower than conventional 50/50.

If your cooling system is working properly, you don't need any gimmicks. I don't know why motorcycles don't run fans all the time, or at least have them come on at much lower temps. Cars don't wait until the needle hits the red to turn on the electric fans, I don't know why bikes do.

 

[yukonerdave]

If you are interested in the R1 R/R upgrade, I've just finished wiring mine in. I was going to wait until I can check to make sure it is functioning as it is supposed to, but then I will post a step-by-step write up in the "How To" section. If you aren't as green as I am with electrical stuff, there is probably already enough information about it on the site.

 

[gamorg02]

I dunno if there are "kits" for the fan switch. You just wire the aux switch in parallel with the thermostat's switch. That way either one can kick the fan on.

http://www.pythonmotorsports.com/vmax/vmax_products/fanoveride.htm

 

[bagherra]

http://www.pythonmotorsports.com/vmax/vmax_products/fanoveride.htm

Thanks for the link. Got one.

 

[richwrench]

My idle used to go to hell when hot & it turned out to be one of the new ngk spark plugs cutting out - threw a new set of champs in it & it's been perfect ever since - just sayin...