rejetting carbs???

Question

2003 V-Star 1100 Yamaha--I'm putting new pipes on and was going to rejet the carb but, the dealership said I don't really need to unless I change the air intake too---that will be next--will this cause blueing or is it really ok to run it this way?

Answer 1

here's a link that will walk u thru step by step to rejet the carbs. http://harleychatgroup.com/index.php?name=News&file=article&sid=10&mode=thread&order=0&thold=-1


it's best to do the stage 1 all at once; pipes, air cleaner (aka air intake) and the rejet. the above will get it very close. putting it on the dyno will dial it in razor sharp....at about 60 bucks an hour. if u are putting slip-on's on, and they're not almost full-open for the pipe, u might not need a full rejet, just a slight tweak on the settings. straight pipes most likely will. the plugs should be a light tan for best mix. ash grey is passible tho is slightly lean. u dont want the plugs to be paper white...that is just too lean and the pipes will blue from the heat buildup.

Answer 2

Are you sure you wanna do that? What is your goal? Just want it loud? Want it to sound "pretty"? Okay, here's my experience and it worked out really well. Bike was a '97 Honda Shadow, American Classic Edition, commonly called "Ace". I fitted a set of DG HardKrome slash-cut pipes, which were much less restrictive as far as total fuel-air flow thru the engine. The Ace carbs were factory jetted with the front cyclider one size smaller than the rear. This was done to make the front cylinder run warmer, since it's more directly in the airflow when being operated. I moved the main jet from the back carb to the front one and installed a new jet, one size bigger on the rear carb. Then, using some tiny, thin washers, I shimmed up the main jet needles to fatten up the idle mixture and, last of all, drilled out the EPA plugs on the pilot jets and tweaked them until I got rid of the backfire or excessive rumble when decelerating with the throttle closed. All of this brought the bike back to more or less the exact same performance as stock, but with a great sound. Not excessively loud and no air cleaner changes. No bluing of pipes. Fuel economy went to hell, though...dropped from 42 mpg to 32 mpg...everything's a trade-off, what can I say? You could get much closer on a dyno or flow-bench, if ya got the bux...Kenny ;o)

Answer 3

I am a mechanic and I say "no it's not safe". I don't know the headers you have but I'd start with 2 #s up on the main jets and replace the stock air filter with a K&N filter.

Bluing is caused by a few things...like not rejetting in the first place, riding with your choke out..TO LEAN! and cheap headers = cheap platting.

Answer 4

I had a KZ-1000, rejetted the carbs put headers on , changed the gearing... I should have left it stock, My advise is go to the new pipes if you want them ,but try it out with the stock jets . This way you test performance for free, why spend money for no results.

Answer 5

your dealership is right, unless you change the intake you will not NEED to change the jets or needle position.

it sound as though you are unfamiliar with this process, so your best bet is to buy a DynoJet kit for you bike. this will contain instructions as well as the recommended jets and needle position for you exact bike.

real carb tuning is a delicate art and it is not likely that you will be very good at it the first time.

you could also bring it to a dyno tuner and have them set the bike up for you. you should figure $350 in dyno time plus labor and parts.

personally I think the dynojet kit is the way to go, provided you own and can use tools. dyno tuning a cruiser might be a bit wasteful. I only dyno tune FI race bikes. cruisers I tune by the seat of my pants.

either route, chances are you are going to get some pipe bluing unless you have full heat shields (or covers, whatever you want to call them.

good luck

Answer 6

It all depends on how they are jetted from the factory, no one can guess. A dyno run with a wide band lambda probe stuck in the exhaust only costs around £30 and will tell you for sure. Beware of dodgy dyno places though. They may tell you it's running lean just so they can sell you a jet kit.

Answer 7

For anyone interested. I have a carb troubleshooting guide from a popular jet kit company, that will explain what mods you will need to perform for optimum engine performance. Contact me for a copy.

Answer 8

you should do them at the same time.order the filter.do it.