Carb Jets...again?

Question

OK, so I've put the pipe on the bike and immediately felt the difference in the midrange. But not being satisfied, I put the K&N clamp-ons on, removing the stock airbox. I only had the take the bike half way down my street to tell I was way too lean. My buddy says I can install the jet kit myself, but the more I look at all the little parts and think about how expensive it will be to replace the carbs if I botch the job, the less confident I feel about it. Especially when Dynojet says you have to sync the carbs and do different adjustments. I thought it would be as easy as unscrewing the stock jets and putting in the bigger ones. Even though I feel comfortable with a wrench in my hand, carbs are a finicky baby. Am I better off trying to find a shop to install them or am I overly worried about nothing? Part of me feels like if they were so difficult to install, why does it seem like everyone has one? How do you know you're dialed in at max performance anyway?

Answer 1

If you can't follow through, you shouldn't be modifying things.

If you botch the job, you're likelier to put a hole in a piston than "wreck the carbs," unless you're really a dolt and cross-thread something.

Answer 2

Well, let me tell you this. Putting on pipes and not jetting your carbs will cause discoloration of the pipes. I put the pipes on my old bike first and ran it no more than a couple hours and it discolored at the exhaust manifolds... So yeah, do that soon.

As far as how complicated it is... I felt the same way as you. "All these parts and very easy to screw up"... Then I called around for pricing and was quoted between 100$ and 300$ to jet the carbs. Most places recommended "Why not do it yourself, its easy and cheaper".. Well, after working up the nerve I did so. The most complicated part of the whole process was squeezing the carbs off of their hoses and out. The actually jetting process to me only like 20 minutes and was flawless. Follow your directions to a T. I don't know what kit you have but I got the Cobra kit and it instructed to turn the screws 1 1/2 times. I did so but after starting it up I had a little bit of popping so I richened the mixture up and the problem went away. It really is EASY to do a stage 1 kit. Don't be intimidated, just take your time and make note of everything you do. If you mess up for the most part, a mechanic can make a few adjustements and your set to go.

Answer 3

SIgh it seems that every time one of you think you know what you are doing you don't
First changing the air box was ok. Adding K&N air filters was ok but to change the mai jets without first changing the needle settings is nuts. What needles you ask, well the slide in the carb goes up and pulls a neddle out of the main jet.
It is held in place by a clip. It richen up the mixture you lover the clip
Lets say it is in the middle and there are 5 groves.
Move the clip down so it is in slot 4 and try it again. If still to lean, go to step 5. If still to lean, put in the next size main jet and drop the neddle to slot 1 and try it again and if still to lean raise the neddle 2nd notch and so on and so forth.
This is how you tune a carb.

Answer 4

Always give year, make, engine size and model # when asking questions. We need all of that info to give an informed answer.
If your bike is a Kaw Vulcan 750-800, don't attempt the job yourself.
If your bike is an in-line four cylinder, the carbs will need to be synchronized. Unless you have carb sync gauges,
again - don't attempt.
A V-twin is do-able by an inexperienced mechanic. But I suggest you get a shop manual.
http://www.motocom.com/motorcycles/
Dyno-jet jet kits come with a carb troubleshooting guide to help you with the fine tuning.
Installing a jet kit is fairly simple.

Answer 5

Rejetting is not so difficult, but to get it spot on, expect to need some dyno runs. Get a friend to help you that has been through this before if you can. It usually takes a few sets of jets, and a few settings adjustments on the needle positions to get everything exactly right.

The reason everyone has them, and have little knowledge on how to do this procedure, is because many ridrs are too ignorant to realize thata pipe job usually requires rejetting... all they want is the noise.

Here is a source I have used in the past:
http://www.factorypro.com/tech_tuning_procedures/tuning_carbtune,CV,high_rpm_engines.html

Answer 6

the best way i found to adjust a carb is ;close the the both jets then open the jets 1/4 turns at a time(air and fuel ) the same till the engine starts then do your find tones in mix.