2012+ WRs: fuel "percolating" when hot ?

Ya know what, I buy it. I'm glad mine doesn't do it. Next time I take my tank off I might look to see how feasible it is to add a little insulation just as a preventative measure. 

Yeah, I'm astounded that this is even a topic of discussion.

If you ride in really tough terrain on a hot humid day, the gas boils on certain bikes that run hot. 

Usually bikes with stock exhaust lean jetting/mapping, where the heat just does not escape properly.

 

It was so common on the old XR600's with oversize tanks that it would freak people out that the tank was going to 'explode'.....

It has nothing to do with FI or fuel pumps.

It's all about heat. 

The WR has a large motor in a compact frame, so nothing transfers heat away very well.

 

Never had overheating issues with my '13 WR before I sold it.  I had 80 hrs on it, all singletrack and some quad trails. (FMF exhaust, rich mapping, CO level adjusted richer.)  However, I never ran the bike in hot weather.

 

I ended up with a 2009 YZ450 and although it has not boiled over yet, I don't want to take that chance.  No coolant overflow tank but I intend to add one.   I did some searching and found a Boyesen Supercooler that replaces the oem empeller and cover.  All the reviews were positive, most people claiming it solved there overheating problems.  One of the reviews was from a 2012 WR450 owner.  This is his review:

 

"Before installing the bike would operate at 210-215 degrees F, after installing it runs at 170. I really doubted a new impeller would lower temps much but it absolutely works."

 

I ordered one this week.  They are expensive but it appears that it is very effective based on what I've read.  Do a search for Boyesen Supercooler on Rockymountainatv and read the reviews. 

Edited by Navaho6

Moving more water will do nothing unless you are moving more air

The YZ needs it because it has tiny radiators

The WR's have huge radiators; they don't need more water flow.

 

I challenge anyone to measure their temp at 170 at race pace on a steep hill.....that's not realistic.

Apparently it does a lot more than nothing.  Many reviewers reported that the overheating issues were solved by moving more water, several of them racers in race situations.  Zip Ty Racing used them in their desert bikes.  The slightest drop in temp reported was 10 degrees.  I'll take that.

Apparently it does a lot more than nothing.  Many reviewers reported that the overheating issues were solved by moving more water, several of them racers in race situations.  Zip Ty Racing used them in their desert bikes.  The slightest drop in temp reported was 10 degrees.  I'll take that.

 

Yes, on the YZ.  Not needed on the WR. 

If I had any motorcycle that was boiling the fuel, I would be looking for ways to reduce heat.  I would start with a fan because that's what most manufacturers use to fight the problem.  If that doesn't suffice, then the Supercooler would be next.   I can't put a fan on my YZ without having to mess with added batteries, so that's why I got the Supercooler.  Either option will work and both cost about the same.  

 

It is a scientific fact that increasing coolant flow rate will improve cooling as long as you don't go overboard to where it causes aeration and foaming.

Edited by Navaho6
I can't put a fan on my YZ without having to mess with added batteries, so that's why I got the Supercooler. 

 

I suspect your YZ has enough power to run 1 or more PC type fans.  Some of the 92mm variety are rated at ~ 50CFM and at higher pressures.  They draw almost nothing and weigh about 1/2 pound.  I'm going to try one on my (battery-less) WR.

Moving more water will do nothing unless you are moving more air

The YZ needs it because it has tiny radiators

The WR's have huge radiators; they don't need more water flow.

 

I challenge anyone to measure their temp at 170 at race pace on a steep hill.....that's not realistic.

What if you had the larger impeller on a YZ and then decided to add oversized rads?  Would you put the stock impeller back in?

No.  I read several reviews where the rider used both the Supercooler and oversized Fluidyne radiators for fighting the extremes of riding sand dunes in the middle of the Summer.  A lot of guys using Engine Ice too but I will stick with Water Wetter and Ethyene Glycol/water mix.  If I do boil over or puncture a hole in the radiator, I can nurse it back to the truck by refilling with water from my Camelback, which I've done before.

I suspect your YZ has enough power to run 1 or more PC type fans.  Some of the 92mm variety are rated at ~ 50CFM and at higher pressures.  They draw almost nothing and weigh about 1/2 pound.  I'm going to try one on my (battery-less) WR.

 

That's good to know.  I have a fan on my '07 KTM 450 EXC and it still overheats quite easily in the warmer months.  A fan by itself may not cure overheating.  A fan and a higher flow rate (Supercooler) helps solve both problems.   

Edited by Navaho6

3 rides (10+ hours), no more fuel percolating.

 

I made 2 significant changes.

 

1) 08 YZ exhaust cam

2) I covered the bottom of my fuel tank with aluminum duct (HVAC) tape, used to seal joints on ducting.

 

I hope this helps someone.

3 rides (10+ hours), no more fuel percolating.

 

I made 2 significant changes.

 

1) 08 YZ exhaust cam

2) I covered the bottom of my fuel tank with aluminum duct (HVAC) tape, used to seal joints on ducting.

 

I hope this helps someone.

 

 

perhaps you are improving as a rider and can now ride in other gears other than 1st.  that is another possible explanation for what fixed your problem, without any real data there is no real way to tell;  it's just guesswork and my guess is just as reasonable as yours.

perhaps you are improving as a rider and can now ride in other gears other than 1st.  that is another possible explanation for what fixed your problem, without any real data there is no real way to tell;  it's just guesswork and my guess is just as reasonable as yours.

 

OK then.  Must be coincidence that the fuel boiled on every ride before and none since.

OK then.  Must be coincidence that the fuel boiled on every ride before and none since.

 

precisely.

My '12 makes the same noise, never really thought much of it as the weather has been hot/I've been riding hard in the month or so I've had it. I'm about to put YZ cams in it and will also use some kind of heat deflection under the tank. In the mean time I'll check if my tank pressurizes/fuel heats up. Love your thread on weight reduction too, looking forward to losing some kg's.

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