Problems 30 mins into break in on 07 WR450F

I finally got to ride my new 07 WR450 today, I rode it in a field/parking lot for approx. 30 minutes (10 miles), it ran fine, then I heard a loud bang/pop/backfire, then the exhuast sounded thinner, it started popping on decel, and I lost a little power. I rode it back to the truck (.4 miles) and let it cool for 30 mins. I started it again rode about .4 miles and the same results.

Engine mods consist of: Dealer installed GYT-R AIS removal as per instructions which includes: grey wire, snorkel removal, yz throttle screw, and exhaust baffle removal, etc.., also air filter cage was replaced by dealer.

Anyone ever heard of, or experience anything like this? Please advise.

I dropped it off at the dealer on my way home, my 30 day warranty is good until this Thursday. The dealer fired it up heard the noise, apologized, and said they would take care of me. It's just seems wierd that a dealer would say something like that. Is this something they forgot to do when removing the AIS? or during initial set up?

Thanks for your help

Sounds like something caused it to go way lean all of sudden. I would let them fix it and challenge them to fully explain to you what they found so you can ride it with confidence knowing that it will not happen again... I would guess that once the mods are done your 30 day warranty would be void anyway :applause:

Could be a fuel restriction, maybe something got in the carb or float valve to prevent adequate fuel supply

Mods only affect the warranty if the mod causes the problem. Being the dealer did the work, used Yamaha parts, I would expect that even if a mod caused the problem, either Yamaha or the dealer is responsible for it and would eat the cost of repair.

No matter what the problem is, once resolved, be sure to have a complete written explantion of the issue and what was done to reapir it.

Thanks for the response Guys.

How would a bike just become too lean in 30 minutes? Is this something like the needle clip slipped?

Any idea of what caused the pop/bang/backfire noise I heard that started the whole thing.

I plan on getting a written explaination upon pick up of the bike, because it is brand new, happened on the first ride, and just in case it happens again.

Thanks again for your input.

I bet a jet got plugged up.

It's not uncommon on a new bike.

My dealer always turns the gas on then off and dumps the fuel in the float bowl.

It could well be bad gas or shavings of plastic from the new tank clogged stuff up. Hopefully that is all it is. Good call, Beezer!

My own WR (an 08) from the dealer had a plug gap set to nearly twice factory spec, causing cold start to be a pain. **It happens.

I guess I should check the plug on mine too.

Maybe the same guy that put your plug in put mine in.

Mine doesn't like to start cold with the e-start.

Mine doesn't like to start cold with the e-start.

Mine doesn't either

One of these days I'm gonna zap the battery with the battery charger for a few hours and change the plug and see if that allows it to start better. Until then I'll kick

As to the OP's problem...maybe there is a leak at the block off plate or one of the vaccum plugs on the AIS kit.

After I did the plug, I found my bike still did not like cold starting without a few twists of the wrist before pushing the E button. I swapped out the #68 starter jet for a #72. Now, I pull the choke, press, and go. Might have to go down a size on this in warmer weather though...

I've tried the bigger starter jets but when it's cold out I just spray starting fluid into the air boot and kick it.

You haven't lived luntil you've ridden with carbide studded tires on snow and ice.

I don't think the starter has enough power to spin the motor fast enough when it's cold out. I have my battery on a battery tender too.

Okay guys here it is, in writing, from the dealer service dept:

Diagnostic Work-

"Inspected unit and found plug for AIS kit popped off. Upon further investigation found AIS kit was the wrong one. It was for a 2006 model. Installed correct AIS kit for unit and test ran unit all ok. No charge".

Anybody have any comments? Anything I shoud watch for from running so lean?

Thanks

Okay guys here it is, in writing, from the dealer service dept:

Diagnostic Work-

"Inspected unit and found plug for AIS kit popped off. Upon further investigation found AIS kit was the wrong one. It was for a 2006 model. Installed correct AIS kit for unit and test ran unit all ok. No charge".

Anybody have any comments? Anything I shoud watch for from running so lean?

Thanks

Watch out for jacked up mechanics it sounds like...might want to check all your nuts and bolts to make sure they use the ole' rightey tightey lefty loosey rule.

Wow! The DEALER installed the AIS kit and installed the wrong one? Run away! If anyone's gonna F up my bike, I want it to be me!!!

The only advice I can offer is that you stay away from that dealer, read up here on TT every day and learn your way around your bike. The more you know, the more you can deal with situations that come up. I work at a car dealership and we had one idiot woman get her car towed in because the coolant was low and she was completely helpless in the situation. The light came on when it was 15 below and she had no idea what to do.

I've got my 8 year old daughter helping me change plugs on her XR70!

Okay guys here it is, in writing, from the dealer service dept:

Diagnostic Work-

"Inspected unit and found plug for AIS kit popped off. Upon further investigation found AIS kit was the wrong one. It was for a 2006 model. Installed correct AIS kit for unit and test ran unit all ok. No charge".

Anybody have any comments? Anything I shoud watch for from running so lean?

Thanks

In defense of the dealer, when was the bike set-up? It's an 07' and I specifically remember a bunch of sheet regarding GYTR AIS removal kit P/N's in early 07' and they were getting wrong parts in them etc...

I think your fine, I would not expect any damage as a result:ride:

The dealer didn't have the updated AIS kits, and someone from Yamaha told them it was the same with the exception of the block off plate (the ending part numbers are -00 for 06, and -01 for 07/08 the rest of the numbers are the same). They had block off plates, but for some reason didn't use the correct one.

If no damage, I'm okay with it, I'll just service it myself ,or elsewhere next time. When I purchased the bike, I had them throw in a AIS kit with installation, and replace with the updated air filter cage (hmmm, maybe I better chack that too?). This dealership is big and well known around here, they stock many bikes, and have (had) a good reputation, but they are expensive.

You know there's always that "one guy"........ I'm sure we all work with one of them........

I rode it in the street when I got it home, seems a litle more responsive now, can't wait to get it on the trails.

Thanks again for your input guys.

Sounds like the rubber cap from the kit came off or was not zip tied in place and it is sucking air through the port.

G2

Im leaning towards a jet was not tightened and either came out, or is not spraying.............Dosent sound life threatening though, i think its just a carb boo boo.

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