Overly high fuel consumption

[Max_Power]

Hey all!

I'm currently getting around 100kms (about 60miles) out of a full tank before the fuel light comes on, which I thought might have been pretty normal given the mods, but then I looked more into it and discovered that something must be wrong

She's an '04, with stage 7, UFO 4-2-1, vboost always on, and about 16000kms.

I'm guessing it must be a jetting issue, but I don't know.

Is there anything I can do besides taking it to a shop?

Thanks in advance!

 

[davesax36]

What mains?

 

[Max_Power]

What mains?

Not sure as I bought the bike used with the kit already installed, but I have all the original parts and packaging etc. Would it be easy enough for me to figure out?

 

[davesax36]

I'm not sure what actually comes with a real stage 7 setup. You could at least pull the needles to see where they're set.

 

[Hellboy]

Maybe a dumb question, but have you actually checked the consumption or are you just trusting that the fuel light is correct? How many mpg are you getting. With stock carbs and aftermarket exhaust my light come on at 95-100 miles and I get 35 mpg. 15Klm's / liter and that's being careful.

 

[sdt354]

Something is very wrong with your set up. Start with engine condition-all 4 firing?. Then a plug read. Air filter condition isn't a bad thing to check. If your doing this yourself, all you need to know is in the threads here. Basic tools and a carb synchronizer are needed. If I were you, I'd hook up with other Vmax guys in your area. I'm sure you'll get someone to help you out. We do that here, all the time, which is why this forum is the best.
Steve-o

 

[Miles Long]

Maybe a dumb question, but have you actually checked the consumption or are you just trusting that the fuel light is correct? How many mpg are you getting. With stock carbs and aftermarket exhaust my light come on at 95-100 miles and I get 35 mpg. 15Klm's / liter and that's being careful.

Not a dumb question at all, Mr.Boy. A very good one!
Max Power - given the modifications, probably a carburation issue, but as Hell suggests, first make sure that the fuel light is calibrated correctly.
The stock fuel tank capacity is 15 liters, with 3 liters being the reserve amount.
So you should be pumping in 12+ liters to top off the tank, following low fuel light activation. Make sure this is correct, before digging into those carbs.
Cheers!

 

[Max_Power]

Not a dumb question at all, Mr.Boy. A very good one!
Max Power - given the modifications, probably a carburation issue, but as Hell suggests, first make sure that the fuel light is calibrated correctly.
The stock fuel tank capacity is 15 liters, with 3 liters being the reserve amount.
So you should be pumping in 12+ liters to top off the tank, following low fuel light activation. Make sure this is correct, before digging into those carbs.
Cheers!

Ya that all sounds about right then, shortly after light comes on I'm always putting $15 worth @ around $1.29/liter

 

[Max_Power]

Something is very wrong with your set up. Start with engine condition-all 4 firing?. Then a plug read. Air filter condition isn't a bad thing to check. If your doing this yourself, all you need to know is in the threads here. Basic tools and a carb synchronizer are needed. If I were you, I'd hook up with other Vmax guys in your area. I'm sure you'll get someone to help you out. We do that here, all the time, which is why this forum is the best.
Steve-o

ya thats what I was thinking too, ordered a carbtune this week actually and I'll check the plugs and filters then too. But otherwise the bike is running and sounding great.

And ya, my step brother in town actually has a vmax as well with similar mods, and he's the one who told me that he gets about 160kms before hitting reserve, but he told me to take it to a shop to get the jets looked at.

 

[DMAN999]

Not sure as I bought the bike used with the kit already installed, but I have all the original parts and packaging etc. Would it be easy enough for me to figure out?

Yes, the Dynojet Stage 7 kit comes with DJ165 and DJ175 Main Jets.
http://www.dynojet.com/pdf/4716.pdf
Stock Yamaha Main Jets were Mikuni 152.5 jets.
So, see what size is left in your kit and that should tell what size was installed on your bike.

 

[dannymax]

Has the mileage suddenly taken a nosedive or is this a new bike for you? If new to you have you determined the plug gaps are correct, float settings are in spec, valve lash is in spec, sync, etc. ?

Lots of things other than jetting can affect mileage.

 

[Max_Power]

Has the mileage suddenly taken a nosedive or is this a new bike for you? If new to you have you determined the plug gaps are correct, float settings are in spec, valve lash is in spec, sync, etc. ?

Lots of things other than jetting can affect mileage.

I bought her last summer and put almost 2000kms now, but the mileage has always been this bad.

 

[Max_Power]

Yes, the Dynojet Stage 7 kit comes with DJ165 and DJ175 Main Jets.
http://www.dynojet.com/pdf/4716.pdf
Stock Yamaha Main Jets were Mikuni 152.5 jets.
So, see what size is left in your kit and that should tell what size was installed on your bike.

Excellent, I'll look into that tomorrow

 

[davesax36]

Plug gaps really do make a difference.

 

[vladthedog]

I had a similar issue. It was running too rich. I bumped the needles in one notch, and it's never run better. Plus I'm back up to about normal mpg.

 

[Max_Power]

Yes, the Dynojet Stage 7 kit comes with DJ165 and DJ175 Main Jets.
http://www.dynojet.com/pdf/4716.pdf
Stock Yamaha Main Jets were Mikuni 152.5 jets.
So, see what size is left in your kit and that should tell what size was installed on your bike.

That was easy, I have the 175's installed

 

[Max_Power]

I had a similar issue. It was running too rich. I bumped the needles in one notch, and it's never run better. Plus I'm back up to about normal mpg.

I'm trying to find instructions on here on how to do this, but cant find it.

Anyone know of the thread I'm looking for, assuming it exists?

 

[fmcandrew]

Your needles are in your slides under the carb covers facing out on both sides. Look inside the slide (your needle will be sticking out the back side) and you'll see a large plastic screw down there...use a large head flat screw driver and take that off. Once off just tip the slide over in your hand and the needle (along with a spring & washer) will fall out. The needle is notched at the top (blunt end). You will see a C clip holding a peice of plastic on the needle...that is what must be adjusted. If running rich, remove the C clip...move it up one slot (closer to blunt). Do this for all 4 carbs. Now reinstall...I put the washer on the needle, place that in the slide and make sure you turn the needle until the little nipple finds its hole. Then I use a small alen wrench to help get the spring inside the same hole as the needle...then drop the large plastic screw in and do your best to align over the spring and snug it down.

Not very hard...did all 4 of mine last night in about 45 min from start to finish.

 

[Max_Power]

Your needles are in your slides under the carb covers facing out on both sides. Look inside the slide (your needle will be sticking out the back side) and you'll see a large plastic screw down there...use a large head flat screw driver and take that off. Once off just tip the slide over in your hand and the needle (along with a spring & washer) will fall out. The needle is notched at the top (blunt end). You will see a C clip holding a peice of plastic on the needle...that is what must be adjusted. If running rich, remove the C clip...move it up one slot (closer to blunt). Do this for all 4 carbs. Now reinstall...I put the washer on the needle, place that in the slide and make sure you turn the needle until the little nipple finds its hole. Then I use a small alen wrench to help get the spring inside the same hole as the needle...then drop the large plastic screw in and do your best to align over the spring and snug it down.

Not very hard...did all 4 of mine last night in about 45 min from start to finish.

Perfect, thanks!

 

[alorio1]

I would raise the clip on the needles one notch (move clip towards blunt end) , check plug gaps and close vboost putting it back to normal operation to increase mileage.