Sled seizes, wait 2-5 min, then runs again!

dirtjumper895

dirtjumper895

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Suffolk, VA
Sled is a 06 IQ440.


You can run the sled, easy or hard for varried amounts of time. All of a sudden, the motor will seize, and can not be pulled over. However, if you wait for about 5 min, it will be unlocked, and you can ride it again. Its happened twice now. After the first time, we pulled the head/cylinders off, everything looks perfect. No scratching, and can still see crosshatching. No telltale signs of damage.


My only idea is that the sled could be like vapor locking, but not sure if its possible. Any ideas????


It sure is weird.
 
Had me worried Jeff when i saw the post title. I was thinking the worst about yours, after you told me it was running good. Is this the sled that hooked up to the strap at the gas station Friday?
 
my uncles doo did this with under 500 miles. cruisin down the side of the road when it locked up solid and he got rear ended. dealer couldn't find any problem and never did give him a diagnosis. crank bearing went out at 2000 miles.
 
Drew-

Nope that was a different IQ with a 660 in it.... He ran out of gas. Is there anyways to check crank bearings? When we had it apart, we tried to feel for any slop between the primary and the pistons, and didn't feel anything. He does have the center bearing lubed with a manual primer knob, and he keeps it lubed frequenly while riding.


As for rocking the primary when its locked, we haven't checked that. Once it locks again, we will.
 
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my doo - 2000 700 twin - 2026 miles ...... you got it! Crank Bearing.

It died, ran again, died, ran again and then died - lock up good that time!

that's why I got back on the Yammies!!!
 
dirtjumper895 said:
Sled is a 06 IQ440.


You can run the sled, easy or hard for varried amounts of time. All of a sudden, the motor will seize, and can not be pulled over. However, if you wait for about 5 min, it will be unlocked, and you can ride it again. Its happened twice now. After the first time, we pulled the head/cylinders off, everything looks perfect. No scratching, and can still see crosshatching. No telltale signs of damage.


My only idea is that the sled could be like vapor locking, but not sure if its possible. Any ideas????


It sure is weird.
Click to expand...

Two things may cause this...
1) improper piston to wall clearance, needs to warm up well before getting on it (common with race engines & aftermarket pistons)
2)Is it extremely harder on fuel this year...if so was the carbs serviced...if not, then its loading up on fuel & creating a hydraulic lock & frees up after the fuel evaporates or pressure is equalized...
When cold take plugs out & belt off, use a stethoscope & listen to the lower end you will hear a defined noise & compare it to identical engine for comparison...is this a one owner sled? How many miles on it? was it recently purchased from a private sale?
Just trying to help here...keep us posted...
 
the sled is an 06, however it was purchased in September new from a private seller. The motor only has maybe 300 miles on it max. As for warming the sled up, it is always warmed up before ridden, so i do not think it improper clearance. The carbs were recently serviced, just to swap out jets for the climate he rides in. (the U.P.)
 
I just talked to him. He says he is still running quite fat in the mid range on the needles, and that has been at the throttle position in which it has been locking up. Needles are the 02 PRO-X needles, so a lot of fuel is being dumped in. Going to go tomorrow and get some shims, to lean the needles by half sizes... Will report back.
 
Does the moter have drain plugs for the crankcase.Front side under pipe?If it does pull them out when it happens for a check.
 
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