Bike running super rich-spark plug chek

Hello all,

since I bought my 93 Vmax I noticed that one of the red reserve light shows up at around 60-65 miles after full tank, no problem on the sensor because its really takes 10 litters to fill. Now that I got reed of my other problems in the bike, this is the last one remaining (at the moment), I'm not a mechanic so I did some research, and this problem is suppose to come from the carburettors, but I read that when it comes from them its also that bikes doesn't run good and the spark plugs can tell by the colour.
Well, In my case the bike seems to run good and throttle responding fine and the plugs don't seem to tell much bad according to my experience and research. The bike is still stock.
Could you guys give me an advice of what can be the cause of it?

I asked the same question last winter..
http://www.vmaxforum.net/showthread.php?t=36189

one guy said, they looked good and that he wished his looked that way..

IMHO, Yours looks rich.

Yep.....they look a little bit rich. Did you buy the bike new....or used? The reason why I'm asking.....I wonder if the previous owner got into the carbs.

Here is a pic that will help diagnose WHERE the carbs are too rich.

Have you confirmed your carbs are stock internally? stock exhaust ? stock air box no mods at all ??? mileage on bike? compression check ? if your bike is completely stock and your gas mileage is that bad something must be wrong, some guys with completely stock bikes will shim their needles and go to 147.5 or 150 mains for a little bump in performance but I don't think that would explain your bad gas mileage and sooty plugs IMO i'm sure someone with a lot more knowledge than me will chime in i'm just learning too !! good luck

Traumahawk said:

Yep.....they look a little bit rich. Did you buy the bike new....or used? The reason why I'm asking.....I wonder if the previous owner got into the carbs.

Here is a pic that will help diagnose WHERE the carbs are too rich.

Click to expand...

LOL I told you someone with more smarts than me would chime in, we must have been typing at the same time

scuff said:

we must have been typing at the same time

Click to expand...

LOL....I was thinking the same thing....

First question is how many miles on the motor? Damn i luv it when when they spell carbs with 2 t's and color with a "u" ---- that looks soooo cooool.
Next you say "stock" so i assume that the carb A/F mixture screw caps have not been drilled out and removed.
If they are could you turn them in 1/2 turn at a time (easy) until they close they back them out to where they were before.
Let us know starting with the front left carb#2 then we will figure from there.
2nd is are the plugs gapped between 32 & 35?



If you are getting 65 miles to a tank you are running rich or you have a gas leak somewhere.
Your plugs need to be more of a tan colour ( damn that was cool putting that "u" in there).
I can see deposits on the plugs which shows ring wear, valve seats worn and possibly enrichments on your choke. The latter being my guess with such a jump in lower mileage.
If you can get back with some details we can narrow down where the problem is-
In the meantime i am going to borrow my girlfriends computer that she bought in the UK that has as the cool knobs on it for spelling right.:rofl_200:

Try setting the carb floats to the correct specs. That is one possibility and has been in issue I had with these carbs. Had a similar rich condition that came out of nowhere and was a stuck float plus all floats were set wrong. Used anything is just that, used and abused.

lastwhiteman said:

try setting the carb floats to the correct specs. That is one possibility and has been in issue i had with these carbs. Had a similar rich condition that came out of nowhere and was a stuck float plus all floats were set wrong. Used anything is just that, used and abused.

Click to expand...

+1 17mm on float height.

So.....next question.....have you had this problem for as long as youve had the bike.....or has this been a sudden onset problem?

Before anything, thanks for your replies and expertises advices. I have no clue which spelling check was activated but if it wasn't you would be rolfl, since English is not my native language:biglaugh:.
I bought the bike last year around this time with 17400 miles which so far made around 300 miles more, how can that interfere?

When I bought it, the previous owner said that at a bike shop carbs were clean and they changed the parts from this picture, he said this was replaced but he couldn't tell me exactly the reason, atthat time I ddidn't know what that was, I assume that they replaced for the same ones, which seems stock to me. Can it be that they didn't replace this parts and only removed?

since I have the bike this have this low fuel mileage.

I've never checked the carbs because I don't have any experience about it and I'm afraid to screw up anything, because of a baby and a 2 years old daughter I have very few spare time to explore and learn, also a garage would help which is something I don't have the possibility to have. Also i don't know anyone who knows about opening carbs. But since i will have know more about it, at least in order to know if it's well set up. Is there much big differences from other carbs to the vmax carbs?

What made think the bike stock is looking at exhaust and the guy said the cabs were taken care in a bike shop i believe they would not put different meddles.

But at least i know now that the spark plugs are indicating me to check the carbs.

Oh! The air filter i cleaned recently, with air pressure, no dust came out at all. I didn't took a picture at that time but the filter was white instead of red/orange from the manual one.

Unfortunately I don't have the tool for the compression check and the rond tool for the spark plugs gapping.

In the photograph..... are all of the springs the same length...or is that just a pic that the previous owner made?

There is a lot of knowledge on this forum.....we can walk you thru anything...and tell you if you can do it at home with simple hand tools.

The picture I made today.

The only mod I can see that the bike has is the short rear which doesn't seem to be very popular around here on the forum.

Also something that I noticed that happened two months ago was I used the vboost once while riding and after that no more sound after turning the key, also no vboost at up to 7500 rpm. But it shouldn't affect much the running rich problem. I believe.

Also I found that when bike is at idle and every time I pull the clutch lever I feel a difference in the engine sound, wonder if I'm getting already crazy with this cursed bike or it means anything.

OK. ....so are all of the springs the same length.....or is one shorter? Also....a change in sound of the engine when the clutch is pulled in....is considered normal.

That noise is just your clutch discs and pressure plates banging around and is really not a problem--
Do you know where your a/f mixture screws are set? Are the plugs taken out so that you can check how many turns out they are?

Your white air filter is stock--reddish or orange would be an aftermarket K&N.
If it had high mileage it could have bad valve seats, worn rings and easier to blacken your plugs.
I am a firm believer in running the best plugs i can find and if you do not want to go into the carbs my suggestion would be to get a set of iridium and very carefully set or look at the gap (around 32-35 for stock) and these will probably raise your mpg as they will burn off excess fuel. Your bike will run better and mileage should improve-your plugs do not look all that bad right now.
You need to check turns out on A/F mixture or change to a smaller main jet. You probably have 152.5
And you would need 150 or 147.5

To get an accurate plug reading you must run the bike with a lot of power applied for a munite or so or longer then chop power, kill ignition and stop, then check the plug color.
Any time spent idling or slow driving will give a false reading.

Best for the aluminum heads plug hole threads to let the engine cool before removing or installing plugs if possible.

Why were the stock jet needles replaced? If the stock jet needles were replaced with thinner ones, that would explain the increased fuel consumption.

wayne z said:

Why were the stock jet needles replaced? If the stock jet needles were replaced with thinner ones, that would explain the increased fuel consumption.

Click to expand...

I think those are stock....I'm not seeing other grooves for the clip.