Sputtering Whizzers

peter nap

Local time
1:31 PM
Mar 4, 2008
My son and I took a ride today. I had my 07 and he had my wifes 08.

We went about 10 miles, stopped for a while and came home. No problems
It was hot today, about 102. We stayed at home about 10 minutes and got back on, The both started hard (very unusual).

Got about a quarter mile to the stop light and when it turned green, both bikes sputtered so badly, I thought they were going to cut off. They both did this for another quarter mile and then ran the way they normally do. Went 3 miles more, stopped and got a drink and then went home with no problems.

Could the heat have caused this?

Plenty of gas and oil. Hers has about 70 miles on it and mine has 400.
Howdy Yes the heat can cause this ..things to check .float level , plug burn lean or rich,fuel cap vent ,do you still have heat isolater plate on intake.fuel line routing.these are all things that can cause this problem.. hope this helps Bill Green
Thanks Bill. I haven't checked the float level. What should I be looking for?

I'm running your favorite Iridium plug and it looks a neutral as any I've seen. Gas line routing looks good and yes, the isolator shields are on both bikes.

The caps are a constant problem on both bikes. I had driilled mine but the dealer insisted (As per Dave) that I keep a new unaltered cap omn to keep the warranty in force.

I did open the cap several times during the ride. It did seem it was building pressure quicker than normal. The engine seemed hotter today even I kept a moderate pace (mostly open road).

It may just be that today was hot and the brief time sitting let the carb get really hot...It's pretty disconcerting though. Those engines have always run perfectly.
the gas was probably boiling and did until the float bowl filled back up. the carb isolator is suppossed to keep this from happening.
Hi peter I would agree with stude13, If they always run great but this one time with it real hot your fuel was more than likly turning in A vaper in the carb .Ive had this happen to me once and it had no power from stop until I was running around 20 to 25 mph.then it got enough fuel to cool it. ...Dont know of good fix for this one . maybe Quenton has the fix .. SORRY Bill
Thanks !
I feel a little better. This is extreme weather for here so I doubt any solution is needed. It's supposed to be the same today so I'll see if it repeats.

Sure do love those things.
Hi peter IM going to send out two manifolds to be hot jetted then check temp. difference . Trying to get carb temp down.. Will post results later.. Bill Green
My 99 has done that on a hot day also, I saw bubbles in the fuel filter. Then it went ok after a mile. I've been thinking about putting a coil of fuel line and a pancake fan mounted under the tank, blowing down onto the fuel line and head. The fan would only be used on these hot rides.
Hi all I got back coated intake manifold It looks good and should work well aslong as I put factory isolator between head and manifold .Im still waiting for my cylinder from the machine shop getting bigger piston custom made valves , guide, port word ,all custom and blue printed.. Bill Green