Raptor cranks for 30 secs, fires up & revs super high & makes horrible sound

[bstein333]

I need help!  I have searched & searched with no luck.

We were out with my 07 raptor over the weekend, and it ran solid the whole time.  Then I was going to move the bike closer to our toy hauler to lock it up for the night, and it wouldn't start.  I kept cranking it, and after about 20-30 seconds, it fired up, and revved like crazy to a super high idle.  It wasn't bouncing off the rev limiter, but it was really, really high.  While it was running, it was making a loud noise, as if the exhaust gasket had blown out or something (hard to describe the sound).  Kind of like a super loud whistle.  So I turned the bike off immediately.

Everything looks normal from the outside of the engine, nothing appears broken or loose.  Within the last few months, I have adjusted the TPS to within spec, changed the spark plug, cleaned & oiled the air filter, and the engine oil has always been changed after long rides.  The valves were last adjusted about a year ago.

I can't think of what could possibly be the problem!?!?!?!  Could the valves have suddenly gone waaaay out of spec?? 

Has anyone seen or heard of this?

Thanks for your help!!

The only mod to the bike is a pro design intake.

[Spartan]

It almost sounds like a timing issue but it being stock it shouldn't be...My first check would be setting the motor to TDC and making sure the cam and crank timing marks are lined up. Then check your valves. They could've tightened up a lot...Also are you running a fuel controller?

[Colorado700R]

the super high idle almost sounds like an intake leak...check both the head/TB boot, and TB/intake runner connections.  unwanted Extra air will make it rev up.

Aaron

[Peelz]

I would say intake leak as well. Exhaust leak maybe also.

[Spartan]

Drr yeah I forgot all about that...Mine did the same thing after my TB to airbox boot came off...If you took the intake tube off the TB make sure the bottom lip is seated over the TB.

[bstein333]

Drr yeah I forgot all about that...Mine did the same thing after my TB to airbox boot came off...If you took the intake tube off the TB make sure the bottom lip is seated over the TB.

oh snap...good call, maybe I forgot to tighten the boot back up after adjusting my TPS and it worked its way loose after riding a while.

I'm going to take a look on Saturday, hopefully it's that simple.  The motor is due for some valve adjustment, so I'll probably go in there too.

Thank you all for the advice!! I'll keep the thread updated with what happens.

[Spartan]

Sorry total brain fart on that...I took my tube off not long ago to check the operation of the TB and when I put it back on, the lower lip of the hose folded over and wouldn't seal on it...so when I fired it up it did the same thing when I revved it.

[bstein333]

You were right, the intake boot had separated forward of the throttle body.  Shoved it back in & tightened, and the bike fired right up like new!  I owe you guys large quantities of beer if you're ever in san diego!

Thanks Again Everyone.

[Colorado700R]

[Peelz]

You were right, the intake boot had separated forward of the throttle body.  Shoved it back in & tightened, and the bike fired right up like new!  I owe you guys large quantities of beer if you're ever in san diego!

Thanks Again Everyone.

I hope to be there soon.