gas/fuel/petrol mileage

[4gasem]

Re: gas mileage

You can get 85 or E85 out here in the boonies. Stay away from ethanol, it likes to clog carb circuits and is hard one the o-rings.

Mark
#1098

I remember you saying that several months ago so the last 4 months and 400 miles :bang head: I have been using 87 which is straight gas...

I also use seafoam religously...:thumbs up:

We have E85 here but that's for flex fuel vehicles only. I know a guy that ran that in his Taurus flex fuel vehicle and got well over 250,000 out of it. Not bad for an American car. The alcohol burns a lot cleaner which I am sure helped a ton...:thumbs up:

 

[warbeast]

Re: gas mileage

I've only owned my 2000 for two weeks and noticed that I am getting 28-32mpg. I've read on some of the other threads on here that the 4-4 cobra slash cuts can cause loss of ponies and have too much back pressure causing a little flooding. If I modded the mufflers with a few extra small holes near the exhaust vent at the rear of the muffler, would this help make the mileage a little better?

Thanks for any help guys...

 

[4gasem]

Re: gas mileage

I've only owned my 2000 for two weeks and noticed that I am getting 28-32mpg. I've read on some of the other threads on here that the 4-4 cobra slash cuts can cause loss of ponies and have too much back pressure causing a little flooding. If I modded the mufflers with a few extra small holes near the exhaust vent at the rear of the muffler, would this help make the mileage a little better?

Thanks for any help guys...

Welcome! And you are not to picky with your wording... At least it's legible!:thumbs up:

It may help but I believe the real issue is the pipe diameter. The stock pipes are tiny and the Cobra doesn't help matters. The Cobra pipes are the best looking IMHO but the decrease in power made me go to a full system instead. I usually get only 30-35mpg too but mine is still breaking in and has low miles.

 

[maleko89]

Re: gas mileage

+1 to that. Make sure you're using stock needles...not the ones from the Cobra jet kit. Then, drop your mains 1-2 sizes. Stock is 152.5 which is a bit rich for stock exhaust and way rich for Cobras.

Mark
#1098

 

[warbeast]

Re: gas mileage

+1 to that. Make sure you're using stock needles...not the ones from the Cobra jet kit. Then, drop your mains 1-2 sizes. Stock is 152.5 which is a bit rich for stock exhaust and way rich for Cobras.

Mark
#1098

Do you know if Dynojet measurement increments are relative to factory numbers or are they different? And how hard is it to change these? I've changed them on my old Maxim but The way these carbs sit kind of scares me in regards to tampering with them.

 

[maleko89]

Re: gas mileage

DJ/Mikuni jet comparisons are on vmax.lvlhead.com/tips.

For mains, just need to drain the carbs, flip upsidedown and remove the brass hex cap that's on the bottom of the float bowl. Then, loosen mains slightly and then use a toothpick to remove the jets. Careful, if you drop the jet inside the float bowl you'll have to split the carbs from the rack in pairs and then break open the float bowls.

Mark
#1098

 

[44 magnum]

Re: gas mileage

I've only owned my 2000 for two weeks and noticed that I am getting 28-32mpg. I've read on some of the other threads on here that the 4-4 cobra slash cuts can cause loss of ponies and have too much back pressure causing a little flooding. If I modded the mufflers with a few extra small holes near the exhaust vent at the rear of the muffler, would this help make the mileage a little better?

Thanks for any help guys...

I too have Cobras and have done what you've described. I was basically hoping to get a little more sound. The boys here told me that until I swap out the pipes coming out of the motor that anything I did was probably not going to amount to much. In addition, I was pretty conservative in that I only drilled one hole per pipe and it was only about a 5/16" dia hole! Hehehehe!!!

How many did you drill and what's the approx size you went with?

 

[warbeast]

Re: gas mileage

@maleko89

Ok Just so I don't feel completely stupid, and sorry I know I'm kinda n00bin' it up here, when you say drop 1-2 sizes you mean drop it to 150 or 147.5 correct? Also should I pick one over the other and should I do anything with the pilots? I know that these engines are quite different from most, I just wanna do it the right way without forgetting anything and not have to worry about it.

@44Magnum

I haven't drilled anything yet. I just want to get some details before I do anything. Get the opinions of some experts here.

 

[Chatam/V-Max]

Re: gas mileage

Mid is 87?? What's low?

Low is 87 mid is 89 and high is 91 or 93 depending on the brand... That's here in the plains... 89 is cheaper than 87 but is 10% ethanol.

Yea, here in my parts, 87 seems to be the norm for the mid grade, must be a Colorado/Altitude thing. Does anyone know which stations do or do not use the ethanol in their fuel? This might be a helpful topic for many reading this. Would also come in handy while traveling to other towns. Perhaps someone knows of a web site containing such info.

 

[arZan]

Low Fuel Average

Hi All.

Didnt know which was the best forum to post this in, so if I made an error, apologies.

I am a recent owner of a 1993 vmax.

Got the carbs synched, fluids changed, spark plugs changed etc.

My max gives me low mileage. I fill up my tank and it hits reserve after 60 miles. Ive noticed this in the last two tankfuls.

The exhaust fumes also have a slight smell of unburnt gas.

Is that typical.....the average and the smell ??

I do a lot of city riding here in NYC and have cobra pipes if that helps. Everything else is stock.

thanks

 

[maleko89]

Re: Low Fuel Average

Cobras more restrictive and tend to run very rich. You can try dropping the main jets a size or too and make sure your float levels on all 4 carbs are set to 17 mm. What are you mixture screws set at? Is your air filter clean?

Mark
#1098

 

[arZan]

Re: Low Fuel Average

I have no clue what jets are there inside. The cobras came with the bike.

I dont think i have the capabilities to tinker with the carbs.

If i take it to a shop...what costs am i looking at.

whats the typical mileage per gallon for a stock vmax

 

[maleko89]

Re: Low Fuel Average

Stock Vmaxes get between 38-46 mpg. To swap main jets it takes me 45 minutes to an hour to do but the shop will charge you for more time I'm sure. Another option is to put the stock mufflers back on.

Mark
#1098

 

[vmaxinID]

Re: Low Fuel Average

YO!!

A shout out Callin' any NYC area Vmaxerz to help this Bro out.

I know somebody in the East has the skillz with a wrench to help for the day.



Chime in Yall'.

arty:

 

[shawn kloker]

Re: Low Fuel Average

Chuck and Bob are in NYC.Funnier than hell too.They are not here though.

I'm getting 50 miles to the reserve light.Big heads,cams and carbs will do that though.Need to change my shift light since it cooled down.Keep hitting the rev limiter at 10k with the shift light at 9.5k.The new dyna 3000 is kicking.

 

[one2dmax]

Re: Low Fuel Average

**** shawn, even ricks 1500 tourmaster with flats gets 75 miles to the reserve light. You're nowwhere near that much fuel need.

Sean

 

[shawn kloker]

Re: Low Fuel Average

Yah I need to dig back into jetting it.

I was having problems with my spark plug wires and it wasn't running on all cylinders at thunder.My Dyna 3000 wasn't advancing at all.I was getting alot of false plug readings.I'm running 125 mains now.It keeps running better and better the cooler it gets.I have not fouled any plugs yet though.The thing that sucks is that no one stocks keihin mains around here and any change attempts have to be ordered in at $7-8 a jet.

 

[arZan]

Re: Low Fuel Average

thanks all for the comments.

if i get the clymers handbook does that explain the procedure...

I am mechanically adept and do a lot of the stuff on my other bike....a Norton Dominator from 1957.

But thats another area and a far less complex beast.

 

[maleko89]

Re: Low Fuel Average

Yep, it shows step by step how to remove the carbs. From there, just flip 'em upside down and set on top of frame where your air box was. Remove the brass hex plugs and then you have access to the main jets. Loosen the main jet and then use a toothpick to remove it. Be careful here. If you drop it in the float bowl you have to remove the cover to get it out. Make sure the jet is tight on the toothpick.

Mark
#1098

 

[4gasem]

Re: Low Fuel Average

thanks all for the comments.

if i get the clymers handbook does that explain the procedure...

I am mechanically adept and do a lot of the stuff on my other bike....a Norton Dominator from 1957.

But thats another area and a far less complex beast.

Clymers and Haynes books sucks... Get a factory manual which also sucks but much less than the other two...:thumbs up: The carbs are very easy to remove and service...