idle thumb screw, running problems

[dewcrazzy]

Hi I just purchased a 98 vmax and the only way it will idle is with the choke a little on. The previous owner had the carbs rebuilt over the winter. I don't think has rode it but once since. How do i adjust the idle (pic please) and is there anything I can do to help it idle better. Once it gets past the little chug out of the gate it runs like a scalded dog. Thanks Bob

 

[Traumahawk]

Since it wont idle without the choke, it sounds like its time to do a shotgun on it. Its not hard to do at all....and takes MAYBE an hr to do it.

Here is a link to the website that explains it....and there are LOTS of pics, and if you get lost...or have anymore questions...dont hesitate to ask.

http://vmax.lvlhead.com/tips/shotgun.htm


EDIT...I couldnt find a pic of where the idle adjustment screw is....but as you sit on the bike reach down on the left side, and in the middle between both carbs there will be an upside down screw, with a black plastic top on it. that is the idle adjustment. Right now I cant remember off the top of my head which way to turn it.

 

[dannymax]

Sounds more like an idle circuit problem than an idle adjustment, like maybe the idle jets have gummed up a little. Try the shotgun procedure and/or some Seafoam.

FYI the idle adjust thumb screw is located below the horizontal chrome mounting bracket on the left side of the carbs...between the float bowl drain hoses.

 

[dannymax]

Eric can think faster'n me....I think....:ummm:

 

[Hellboy]

Idling only with the choke on would say to me that the idle mixture screws are set to lean. when you add choke the only thing you are doing is making it richer so it will run. That is why they are called idle mixture screws. If your brass plugs have been removed on the carbs then someone at sometime has adjusted them.

Matt

 

[Traumahawk]

Eric can think faster'n me....I think....:ummm:

LOL...I dont know about that....but who do I call when I have a carb question???

 

[dannymax]

LOL...I dont know about that....but who do I call when I have a carb question???

:rofl_200::rofl_200::rofl_200:

 

[tugla]

think he talks into the mirror in the shop....but guy keeps interrupting him while he speaks lol....

 

[dannymax]

think he talks into the mirror in the shop....but guy keeps interrupting him while he speaks lol....

You been watching me haven't you!! :rofl_200::rofl_200::rofl_200:

 

[dewcrazzy]

Took her out in the last 2 days and put over 100 miles on her. When I got home today I looked for the idle thumb screw and found it. I twisted it to the right and the idle went up, so then I turned the choke off and she stayed running. Will have to take her out over the weekend to see if it's all good now. The previous owner sent the carbs to yamaha over the winter to be rebuilt so I wonder if the idle screw was just not high enough. Thanks everyone for your help. This bike was so much fun to ride.

 

[Traumahawk]

Good...glad that everything has worked. They are fun arent they?

 

[dewcrazzy]

figured since the season has ended I would take the bike to a local shop to see if they can get it to run smoother. low and behold I just got a call the carb bowels were filled with rust. Then he called me back saying the gas tank was a rusted mess. Man, now it looks like a lot of cash out the window. Wish sellers were more honest to buyers. Still love the bike so she will get fixed.

 

[dewcrazzy]

Just got the bike back from the shop. The did a fantastic job and she runs amazing. Didn't realize how smooth and fast these bikes were since it always was gunked up. Vmax is a work of art.

 

[Fire-medic]

Even though a 600 cc supersports bike of today will beat it w/a good rider, since the VMax is torque-laden, and it has a long wheelbase, it's fairly easy to get it to hook-up. There's no-need to go to 15,000 rpm w/these (you couldn't, of-course), 9500 rpm (9K rev limit on the newer ones, no differences, just a downward-marked redline to lessen the potential threat of repeated past-redline damage) is only needed if you are choosing-off against another 120+ hp bike. Even the 150 hp bikes are surprised to see the guts the VMax has into triple digits.

Since you like your bike so-much now, I suggest you invest in a rear wheel to go to radials (you can fit a narrow 18" front radial, though the stock rim width isn't optimal) in either a 17" or 18" rear size, 5.5" wide is what seems to work. Any more than that and it's 'widen the swingarm cutout' time. Seventeen inches gives you a wider tire choice, and since it's shorter in-height than stock, it's effectively shorter gearing. An 18" will lower cruising rpm's and is an effective higher gearing compared to the 17" so you should be able to generate a higher top speed. How-often do you use that, though?

Radials will solve all-sorts of handling issues, but your front & rear suspension have to be in good shape. The steering is much-more precise w/the radials, especially at higher speeds, and much-more confidence-inspiring. Do a search about radials, and see for yourself. unk:

Your shop probably has an older tech or two if they did a good job for you, not that a younger proficient mechanic couldn't do it, but someone who knows carbs and these bikes in-particular can make all the difference.

Just got the bike back from the shop. The did a fantastic job and she runs amazing. Didn't realize how smooth and fast these bikes were since it always was gunked up. Vmax is a work of art.