Bigger carb,whats involved?

[darealblaster]

Zup guys,i was just wondering, whats involved in the installation of a bigger carb? Say all i have is Full exhaust system, K&N filter,jetted obviously. If i were to go from say a 26 to 28mm or to a 30mm carb, do i use the same jetting i had before? how do i know what jetting to use to be the same as before. What does a bigger carb help, i know it helps the engine breath better but what does it give? 2hp? 3hp?? no HP just throttle response?? what does it give.

Thank you in advance.

 

[darealblaster]

anybody? i need some help with this.

 

[zack221]

A bigger carb gives the motor more gas so your jetting will be different from what you are running right now. There might be someone that can get you close on your jetting that lives around your area if they have the same carb that you will be getting. Jetting will change with elevation changes so you couldn't run the same jetting that someone else is that lives at say 5000ft above sea level and for example if your at like 500 ft above sea level your jetting would be different. I would use the original jetting that the carb comes with as a start and then work from there depending on what the carb is doing.

 

[blasterboy805]

You will have to change your jetting depending on the elevation of the area and what you are mixing your oil to the bigger carb will always give it more gas so look at the jets on your carb and the size of the old one and the size of the old one you might want to go smaller but make sure you arent to lean on the oil so if you are going to go smaller just make the oil a little bit fat so you dont hurt the moter and melt the rings

 

[burnin'_oil_2001]

if you use a 28mm you will be able to use your stock carb boot, you will need a throttle cable and to block/disable the oil-injection . if you can jet your factory carb then you will be able to do the swap. i was thinking about getting a bigger carb for one of my blasters- i have an ehs airbox lid, jet kit for the stock carb, oil-injection block-off, and i am going to order a dmc exhaust for it when i get the money. personaly i do not plan on going to wild with this blaster as it is used by my son and whomever is around so i might go as big as a 28mm if the stock carb seems to be too small. if the 28mm is too big i will put in a powernow diffuser to help clean up the lowend. i am also thinking about putting on dial-a-jet on all of my quads since i ride the oregon dunes at sea level, mt. hood at around 3-7k feet and in the deserts of eastern oregon in hopes of making my jetting a little easier. i would think that if you sere to buy the carb and cable from a builder or from vito's they should be able to help you get your jetting reasonably close so that you can fine-tune without worrying too much about your engine blowing. make sure that you post back your choices, results, and anyother info you find out.

 

[Wildcard2]

If you go with a 28 mikuni TM your jetting won't change much if at all. You will have to purchase a different pilot for it as the provided pilot is much too small. You will also have to have a different cable unless you allready have the TORS eliminated. You will also be able to use your stock intake boot with the 28 mikuni, 28 keihin or 30 OKO carbs. Going larger on a carb generally gives a top end performance gain, the flat slide or d-slide design carbs also offer a bottom to mid gain. If you go too big you'll have tuning issues and will loose bottom end. A 28 would be great for a stock to mildly built bike.

 

[royalt67]

Wildcard is dead-on. The only thing I would add, having done it recently, is plan on modifying the filter side. The tube from the stock airbox won't fit the Keihin 28 or OKO 30. I found that a rubber pipe connector(with clamps $4.50) from the plumbing store worked nicely to attach the carb inlet to the airbox tube, after shaving some of the ribbing off the tube. Of course, a direct clamp-on filter would eliminate that prob, but I ran out of money....

 

[specialized7]

uhh i fit a 35mm pwk in a stock boot, but the intake side good luck

 

[PirateBiker]

I installed a 32mm flat slide and used the stock boots, just heated them with a heat gun and I was able to fit the carb in.
The jetting that came with the carb was perfect with the FMF Fatty Gold and the twin air filter.
You will probably have to play with your jetting. Start off rich and work your way down, check your plugs by doing plug chops (Shutting your quad off while under throttle os 4th gear. Then inspect the color of your plug.

 

[97BoredOutBlasta]

yes but to answer your question about the benefits of the carb upgrade, a carb really just ups your potential for power, so if you cant burn the fuel that the big new carb forces in, might as well not have done it. parts gotta coordinate, especially somthing as important as your carb...

 

[ruthless_one3k]

The stock carb is almost to small to start out with so the bigger carb will help out with the mods. Just dont go too big, if you go too big you will have problems with running lean. If you dont have enough air velocity to cause enough siphon on the main jet, it doesn't matter how big the jet is it will run lean because it wont pull enough fuel. with your mods a 28mm to a 30mm should do fine as long as they are properly jetted. Just remember buy for what your going to have not what you have or you will end up having to buy another one down the road. That being said I'm kinda drunk so keep that in mind when you read my advice