G450x stumbles and runs really rough

**Baraboorider** · 05-18-20

Hi guys I have an 09 450x that runs great most of the time, but after a good wheelie this weekend it started stumbling and running badly. She would start and idle ok, but no power and ran rough. I had to go back to the truck, add fuel system cleaner and run it up and down the road several times to get the engine to run smooth again. The bike is bone stock, no mods except a prox piston with 15 hours, 200 hours total. It does drool oil from airbox even though I carefully keep oil level below the high mark. Any ideas?

**Tims1572** · 05-18-20

Sounds like it may have picked up some debris from the bottom of the fuel tanks subtank where the fuel pump assembly is located. It has a screen filter around the pick-up area or you may need to back flush the injector itself.

**Baraboorider** · 05-19-20

Thanks did not know how to access that.
Does the crankcase vent cause these type symptoms or just oil draining off the left side of the bike and TL damage? I'll definitely check that tank screen now that you mention it.

**Tims1572** · 05-19-20

Oil in the airbox is a result of the factory breather. Get a breather relocator kit to get it up to the top of the rocker box. Either the DMD "Dangermouse designs" get ahold of David Bates in Australia. He makes them for 449/511 Huskys and the BMW G450/CCM GP450. David runs the Husky 449/511 owners page on facebook.. He gets a batch of them made a few times a year and sells them through eBay listings. Make sure you get the one for the G450 or the CCM GP450 because the Husky 449 version will cause the hose to hit the frame on our BMWs.

You could also get the Husky 449 ZipTy racing breather fitting but I recommend the DMD as it only requires cutting the gasket to install and have installed a DMD on 1 of my engines and the ZipTy on the other. Both work well.

As for it leading to Torque Limiter damage, That will happen if you let the oil level run low and that can also lead to crankshaft oiling issues as well, which is even worse. Keeping the oil level up to 1050-1150ml at all times is important and the breather being relocated up to the higher position on the cylinder heads rocker cover is the best thing you can do to maintain that proper oil level.

**bello650** · 05-19-20

Originally Posted by Tims1572

Oil in the airbox is a result of the factory breather. Get a breather relocator kit to get it up to the top of the rocker box. Either the DMD "Dangermouse designs" get ahold of David Bates in Australia. He makes them for 449/511 Huskys and the BMW G450/CCM GP450. David runs the Husky 449/511 owners page on facebook.. He gets a batch of them made a few times a year and sells them through eBay listings. Make sure you get the one for the G450 or the CCM GP450 because the Husky 449 version will cause the hose to hit the frame on our BMWs.

You could also get the Husky 449 ZipTy racing breather fitting but I recommend the DMD as it only requires cutting the gasket to install and have installed a DMD on 1 of my engines and the ZipTy on the other. Both work well.

As for it leading to Torque Limiter damage, That will happen if you let the oil level run low and that can also lead to crankshaft oiling issues as well, which is even worse. Keeping the oil level up to 1050-1150ml at all times is important and the breather being relocated up to the higher position on the cylinder heads rocker cover is the best thing you can do to maintain that proper oil level.

https://youtu.be/hUQ8avQA-bM

https://www.befr.ebay.be/itm/DMD-Eng...s/183172885402

https://ziptyracing.com/products/hus...04bf5293&_ss=r

**Baraboorider** · 05-19-20

You are amazing Tim, thanks for the fresh eBay link. International eBay links can be hard to nail down

**Tims1572** · 05-19-20

You can thank "Pascal" for the Links.

I was on my way out the door on my way to work when I typed my reply to you this morning mentioning the breathers.

**Baraboorider** · 05-22-20

Removed tank and inspected fuel and filter. Screen cleaned up nicely, once dry it is snow white. The fuel had a ball of water in it about 8mm across in my catch pan. Reassembled the bike with a new seal, fresh fuel, and seemed to run great for about 5 minutes. Now same issue. I've owned the bike a couple months and put 13 hours on it. About 4 of those hours it has run fine. The rest has been missing and backfiring and stumbling at 1/4 throttle or so. I have replaced the spark plug, cleaned the coil ground, serviced the battery connectors, pulled the injector and back flushed it using a 9 volt battery and carb cleaner, now drained fuel tank and checked screen, The best results were with injector cleaner in every tank. The symptoms returned when I forgot to add it. I would love to trust this bike, but right now she's pretty sketchy. Do I just order a new injector and hope that's the issue? Could it be factory mapping issue? Starts and idles fine and goes well above 1/4 throttle. Just runs like crap if you don't hold it wide open and hold on or let the rear spin. Bypassing O2 sensor does not change it. What do you think?

**Tims1572** · 05-27-20

If you have the power up plug installed the O2 sensor isn't being used anyway so disconnecting it isn't going to do anything if its running with the power up plug installed. Have you checked the fuel pumps pressure and have you checked any or all of the wiring connections from the ECU, relays, FI unit and clean and use dielectric grease on the wirings plugs ?

**Baraboorider** · 05-27-20

Thanks for the reminder! I hauled the bike for 30 hours to Idaho yesterday and when I arrived, it no longer started. The kill switch was my first thought. Cleaned and applied dielectric grease. No fire. Next, tps and other efi connections... WIN! It fires and seems the stumbling is better too. We shall see.

**bello650** · 05-29-20

Originally Posted by Baraboorider

Thanks for the reminder! I hauled the bike for 30 hours to Idaho yesterday and when I arrived, it no longer started. The kill switch was my first thought. Cleaned and applied dielectric grease. No fire. Next, tps and other efi connections... WIN! It fires and seems the stumbling is better too. We shall see.

The engine runs well for 5 minutes, which is already a good thing. The ecu changes is maping with many parameters including the engine temperature. Like Tim say, the O2 sensor is useless in sport mode. If the problems begin after 5 minutes with back fire I think that the injector does not inject enough gasoline with a hot engine. As you explain when opening the throttle body the engines do not go up in the revolution, there is too much air and not enough gasoline. the injection is richer (higher) with a cold engine, with a hot engine the injection decreases. I think before buying a new injector you should trying to clean it with ultrasound machine and a good cleaner.

**Baraboorider** · 06-04-20

Solved!.... To make a long story short, I removed both tps sensors from the throttle body and cleaned each with carb cleaner. Electrical cleaner may have been a better choice, but it did the job. I noted the original position of each tps and was careful to reinstall them as close as possible without having to retune. Cleaning them is very simple. Essentially, unplug the sensor from the wiring harness. Remove the one locking screw, pull the sensor gently off the throttle body to unseat the oring. Soak the cup of the sensor with solvent. Cycle it gently with a flathead screwdriver for a few minutes. It is spring-loaded so it will always return to home. You may feel a very minor friction in spots. Clean until it is very smooth with no friction in the entire stroke. Blow them out gently to dry.
Clean the sensor wiring connector.
Clean out the recess on the throttle body with solvent.
Pack dielectric grease into the cup and the oring and the wiring plug.
Reinstall the sensor into the recess. Align the stem on the butterfly valve first, then twist against the spring to set the final alignment of the sensor.
Set the sensor in place with the lock screw. Plug in the wiring harness and go for a ride! Simple.
I think this bike is prone to water in this Part and Wisconsin is pretty much a floating marsh of muck and mud so it stands to reason. Anyway. Thank you for all the guidance.

**Tims1572** · 06-04-20

Thank you, for the details on your fix for the problem you ended up experiencing.
That sounds as if its a new one, so this is the place to archive the information.
We all appreciate the response back to let us know what ended up being the solution to your problem.

**Baraboorider** · 08-18-20

Originally Posted by Tims1572

Thank you, for the details on your fix for the problem you ended up experiencing.
That sounds as if its a new one, so this is the place to archive the information.
We all appreciate the response back to let us know what ended up being the solution to your problem.

I wanted to add that I did the upper butterfly removal and this also improved the stumbling that I was experiencing. It's much easier when it's warm out. The intake boot was too stiff in winter/spring temps to pull and reinstall. Now that it's warmer out the boot can be worked out and in much easier.

The result is GREAT. I have had NO consequences to pulling this extra butterfly and would recommend it to everyone.

Thanks,

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