Picco tuning/temp issues

[Fritz]

I installed a Picco .26 in my Revo at the beginning of the year. Since I got it over the winter I sealed it and mounted it prior to the weather cooperating. After about 10 tanks of brake in, I got the itch and took it off the beaten path for a little bashing. The temps skyrocketed to way over 300 degrees. I found a leak in the cooling head and a semi stuck brake so I decided to start over. Now, I have it running ok at best. Still not as responsive at take of as I'd like and barely shifting to 2nd gear. The temps are running around 290 already. Any suggestions or ideas would be greatly appreciated. I am running 20% O'Donnell fuel and a Traxxas Resonator pipe.

 

[olds97_lss]

You may want to take the carb off, tear it completely apart, clean everything with DA and a q-tip, then reseal the neck/cinch bolt along with putting a bead of silicone around the silver part the the HSN goes into where the composite meets the aluminum.

 

[Fritz]

So you are thinking I still have an air leak. I did clean and seal it before mounting it. Worth a shot.. Where do Picco's normally run temp wise?? I was thinking 230 - 260 with it tuned to rip it up..

 

[olds97_lss]

Depends on the gearing and how far it's broken in. Picco's generally take about a gallon of fuel before you should really lean on them as their pinch is pretty excessive. After a gallon, the temps should calm down and power should perk up to it's peak.

I would bet that 10 tanks is just scratching the surface of break-in for a picco, especially since it's on a maxx which has a 125cc tank. I know my LRP's took about 12 tanks before they were runnable and about 20 before I felt I could rip on them some. Mine were 150cc tanks.

1 gallon is roughly 25 150cc tanks.
for a 125cc tank, 30 tanks to a gallon.

So... 10 is just barely getting it worn in. Until it's fully broken in, the pinch is excessive causing many issues. Drag, friction, heat, blowby (due to lack of good seal), low power, finicky tune...

Hopefully hitting 300+ you didn't damage it. I'd take it easy until you get around a gallon through it and then see how it does in rough terrain/taller gearing.

 

[Fritz]

Mine is just barely getting there then. I've put about 18 tanks thorugh it now. Have put the last eight or so since the initial temp run away. Should I just keep an eye on it and let it be sluggish for awhile until I put more tanks through it? What do you think about the 290? Too high? Could richen it up and put a few more hours on it then try again.

 

[olds97_lss]

290 is high in my book, especially with an engine that has that much power in a truck that is that light. I mean, if it was the TRX2.5, then 290 would be normal! lol
But I'd expect you to be able to keep it around 250 without too much issue.

You may also want to check for drag, like bad bearings on any of the axles or something.

Which resonator pipe are you running? If it's the dual chamber, it's pretty much the same as a stock pipe... I made the mistake of buying that one on ebay... The single chamber one breaths better, especially for a BB.

 

[Fritz]

Will check on the resonator. I think it is a single but can't remember. I checked for drag issues when the temps went which is how I found the brake hanging so I'm pretty sure I'm good there. Will give it the once over before I take it for a spin hopefully tomorrow. I have a 3.3 that I rebuilt for my brother in law that I need to start breaking in for him too. Trying to get things squared away for the weekend. Don't want to dig out the minor leaguers unless I have too. I have 2 other Revo's that were bought for parts that have turned into friends and family can run them if they want to play.. I am a firm believer in the more trucks the more stupid things than can and will happen..