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Mbiker_101

Gyrt ais removal now terrible gas mileage

21 posts in this topic

Just bought an 08 plated wr450 and found out the guy never removed the AIS kit and other goodies. So paid a shop to put on the ais removal kit and a fmf q4 and now it seems to run much better but while out riding in the desert I got to 27m on the trip od and it ran out of gas? Had to turn on the reserve, thought I may have just forgot to reset the trip meter. But then the next day I was on the road and hit 31miles and it was dead, had to hit the reserve. Went to fill up and it took 1.6 gal, my yz 426 would go 60-70 and then some.

What is the problem? It's killing me that I paid someone to install the gyrt removal kit and now I wondering if they installed all the parts because something is not right???? I normally do all my wrenching and I fear I'll have to just break down and double check all their work.

Where should I start?

Thanks

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when you had the AIS removed and an exhaust installed did you change the jetting?  if not you want to get that changed accordingly the bike may be running very rich.

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when you had the AIS removed and an exhaust installed did you change the jetting?  if not you want to get that changed accordingly the bike may be running very rich.

I thought the same thing although I would expect the FMF would open it up a little more making it run more lean.

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27mpg is very good for a dirt bike, but you should be getting closer to 32/35.

 

You need a parts and services list to see what was actually done.

If you did not get one, never go back there.

 

...but that is why we all run 3.2 gal tanks for 100+ miles per tank

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Yes, they said they changed the jetting to what was included in the GYRT kit, I don't have the bag so I'm not sure the jetting, if someone could post what jets are in the kit I'd love to know.

And I would be ok with 27 mpg... But I went 31 miles on 1.6 gal... So 19mpg should be around 40 mpg

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Sounds like they didn't so much jet the bike as they did throw whatever jets they found in it and it's running very rich. My 04 is jetted mostly per the FMF Q2 specs that came with the bike and runs great all the way around as well as gets in the mid to upper 30's for MPG.

 

I bet if you crack the throttle on the stand you'll see (and smell) a puff of dark smoke coming out the back, you shouldn't see that. Take it somewhere to get it jetted properly.

 

Mike

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Yes, they said they changed the jetting to what was included in the GYRT kit, I don't have the bag so I'm not sure the jetting, if someone could post what jets are in the kit I'd love to know.

And I would be ok with 27 mpg... But I went 31 miles on 1.6 gal... So 19mpg should be around 40 mpg

Yeah, you might want to check your jetting.  I believe the GYTR kit comes with a 172 main which, for a bike that has only been de-restricted and has just the FMF Q4 on it, a 168 would be the most I would suggest.  I have that kit but I also installed the JDJetting kit as I felt the jets with the GYTR were WAY too big.

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I just installed a fmf powerbomb header to match the q4 so jetting will be closer now. You think the 172 is about right for a full system?

Who has the gyrt parts kit and can confirm main and pilot jet that comes in the kit, I know it had leak jets as well.

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Found another posting with the gyrt kit. It came with a #50 Pilot Jet, #175 Main Jet, #110 Main Air Jet and a Leak Jet that doesn't give the size.

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175 is too big for a stock motor

160 is fine

Get a remote fuel screw and learn how to use it properly, so 0-2500 rpm is lean as possible

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Thanks everyone, I'll go lower on the main and pilot, I've got an adjustable fuel screw and it's been tough adjusting because it's way over jetted.

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When I first bought my bike back in '07, before I even rode it, I put on a FMF Slip-On Powercorp, took off the snorkel that sits on top of the air box to let it breathe a bit more, took off the AIS, and removed the grey wire. 

 

As far as jetting goes, I used the 110 Main Air Jet and the Leak Jet that came with the GYTR AIS removal kit, and the throttle stop screw.  The other jetting changes I did were from the JDJetting kit.  Red needle on the 4th clip from the top groove, 168 main and 48 pilot.  Also as mentioned, an adjustable fuel screw, but I have yet to use it.  It's there, I just haven't had an occasion to use it yet.  Even as noted below at 9'600, the bike has run great. 

 

I did that all before I ever rode the bike back in '07 and i never changed a thing until last year when I had the bike serviced.  I ride pretty much all of what So Cal has to offer from 3'500 in Johnson Valley to the top of Sirreta in Kennedy meadows which is 9'600.  The bike has always run great without any popping or hanging idle in the altitude.

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Thanks Kenny, good to know you used the air jet and leak jet from the gyrt kit, those were the two items I had no idea about and thought that with those in I needed the 175 and 55 pilot, now I'll try the 168 main and 48.

How many you miles you getting before switching to reserve?

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To this day, I still haven't gone on a ride and had to use reserve.  The most miles I have put on the bike before a gas stop or end of the ride has been ~105 if I recall.  This was doing a long loop out in Cal City.  Borax Bills -> Randsburg -> El Pasos (Cabled Cabin, Last Chance Canyon, Nightmare Gulch, Opal Canyon) -> Randsburg for gas - BB.

 

Last year I did my first valve job and put in the YZ timed Hotcams for the WR.  Also bumped up the piston by .5 and then went to a 172 main jet.  Since then I have yet to do a ride that has pushed the 100 mile range so i don't know how it affected that aspect.  I haven't bothered trying to do the calculation on the shorter trips with the mileage.  I do too much math at work  :smirk:

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Changed the main jet to 165 because I could pull the drain plug easily, any way I can change the pilot without removing carb off bike, can I loosen and twist to get to the bottom. I'm new to the aluminum frame and it's much tighter than the steel frames I'm used to.

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You might be able to get to it. To be honest you'll spend more time trying. Pull the seat, tank, exhaust , and shock and raise the subframe up . I can do that in 20m easy. You'll have much better access. It's easier in the end.

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Finally got around to getting the carb out of the bike, not as bad as I thought, thanks for the tips. I'm working with thecoolaid and jetting this bike. Can someone confirm the pilot air jet is 70 and the main air jet is 65. My main air jet is 110 and I feel most keep the factory main air jet. Now I need to just order the factory one because the shop threw out my stock jet....

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Finally got around to getting the carb out of the bike, not as bad as I thought, thanks for the tips. I'm working with thecoolaid and jetting this bike. Can someone confirm the pilot air jet is 70 and the main air jet is 65. My main air jet is 110 and I feel most keep the factory main air jet. Now I need to just order the factory one because the shop threw out my stock jet....

Yes, you have the stock numbers right.  When you say "my main air jet is "110", that is what you have in there from the GYTR kit?  Yah, I didn't put that one in either.  I am staring at mine right now :cool:

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Yes, the GYRT main air is 110 and I'm afraid this is a factor in the bad gas mileage, seems like going from 65 to 110 really changes the mixtures. That's why I want to copy others jetting recommendations that seem to work well.

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