Author Topic: Thinking about getting a new carb. (Read 13387 times)

countryboy9799 · « **on:** April 09, 2015, 11:21:35 AM »

Here's my problem

As far as I can tell the carb is a stock Keihin. I finally got my motor back together and it runs. I have been battling this carb from the beginning and I am ready to just scrap it. The problem is the float hangs up and will overflow randomly. I even ordered a new float and its the same thing. I have tried adjusting the float to where it should be and even lower than it should be but I always run rich.

The plug is wet and black and it sputters like its rich too. So I thought I would test my theory by shutting the fuel off and after that 10 to 15 seconds it ran like it should until it leaned out so that tells me the motor is running great and the carb is not working right.

Just looking for thoughts on whether I should keep wasting time with this carb or look at a new one. I would like to keep things close to stock so let me know whats recommended and what I will need like a throttle cable, intake boot and whatever else I would need.

Jerry Hall · « **Reply #1 on:** April 09, 2015, 11:52:08 AM »

Quote from: countryboy9799;52883

Here's my problem

As far as I can tell the carb is a stock Keihin. I finally got my motor back together and it runs. I have been battling this carb from the beginning and I am ready to just scrap it. The problem is the float hangs up and will overflow randomly. I even ordered a new float and its the same thing. I have tried adjusting the float to where it should be and even lower than it should be but I always run rich.

The plug is wet and black and it sputters like its rich too. So I thought I would test my theory by shutting the fuel off and after that 10 to 15 seconds it ran like it should until it leaned out so that tells me the motor is running great and the carb is not working right.

Just looking for thoughts on whether I should keep wasting time with this carb or look at a new one. I would like to keep things close to stock so let me know whats recommended and what I will need like a throttle cable, intake boot and whatever else I would need.

You are missing something real basic and do not need to replace the carb.

Remove the float bowl and turn the fuel on and move the floats up and down. Does the fuel shut completely of when the floats are held in the up position?

The problem is probably with the needle. The rubber seat on the needle probably has a grove, or line that is keeping it from sealing or the needle is not moving freely in the socket in where it slides up and down. Remove the floats and rotate the needle in the seat socket. Move the needle up and down to make sure that the needle does not have the slightest bind. We replace a lot of needles and seldom have to replace the floats.

countryboy9799 · « **Reply #2 on:** April 09, 2015, 12:05:31 PM »

The problem seems to be the float is hitting the bowl and hanging up with the float that came with the atv and the new float kit I replaced it with. That is why I suspect it will overflow randomly. Fuel even ran out the this air vent today.

Jerry Hall · « **Reply #3 on:** April 09, 2015, 06:25:16 PM »

Quote from: countryboy9799;52886

The problem seems to be the float is hitting the bowl and hanging up with the float that came with the atv and the new float kit I replaced it with. That is why I suspect it will overflow randomly. Fuel even ran out the this air vent today.

A lot of fuel has to be getting past the float valve for it to run out of one of the top vents.

If the floats are hitting the float bowl, it should be a simple fix.

Do you have the correct float and float bowl?

Tbone07 · « **Reply #4 on:** April 09, 2015, 08:59:39 PM »

I highly doubt you need an entirely new carb, but it's possible.

I wouldn't waste your money on a new one until you've eliminated all other possibilities

Did you adjust the float tab so far out that it pulls the plunger too far out of the seat, therefore it gets stuck?

Tbone07 · « **Reply #5 on:** April 09, 2015, 09:01:18 PM »

I would install the float without the bowl on, and post a pic of you measuring it, to make sure you have the float height set properly.

I don't know your knowledge level so I don't want to come across as insulting, just trying to nail down the issue

Also post a pic of the old and new float side my side. The more pics the better so we can help you out

udontknowme · « **Reply #6 on:** April 09, 2015, 09:38:56 PM »

first off do like jerry said. inspect the needle tip for any kind of groove or hardening of the rubber. if it doesnt have rubber then maybe it has a wear groove. after that check if the flow stops when you push the floats up. if both of those things ckeck good then maybe your floats are bent and rubbing the side of the bowl and hanging up. i dont recall if the keihin flots can be installed upside down but maybe have a look. i installed some lectron floats upside down once and it took me a few minutes before i figured out why it was pissing out the over flows

countryboy9799 · « **Reply #7 on:** April 09, 2015, 10:29:05 PM »

I am pretty sure the carb is stock, the bowl fits on good but don't know if it's stock. I will get some pics posted on Saturday when my son can take pics.

JesseA420 · « **Reply #8 on:** April 10, 2015, 03:26:28 PM »

properly sealing float valve and proper float height setting should cure your issue. really cheap parts from jetsrus.com remember if it is stock that little rubber tip on the float valve needle is almost 30 years old.

countryboy9799 · « **Reply #9 on:** April 13, 2015, 10:04:23 AM »

I did a little work on the carb and am just getting frustrated. I really question if this is the right carb. I have 2 floats that came with my R and one I bought new and something just isnt working right. I am seriously thinking about just getting a new carb. I can get a 38MM Air Striker for 203 or a 35MM for 184. I think it might be a good investment. What else would I need? New throttle cable?

I have also thought about just getting a new PJ, they are cheaper. I can get this one for just under 140.

http://www.amazon.com/Keihin-016-039-PJ-34mm-Carburetor/dp/B00C178IZ4/ref=sr_1_1?ie=UTF8&qid=1428933656&sr=8-1&keywords=keihin+pj+34

I need to get the choke/idle speed knob anyways and they are 30 bucks right there.

countryboy9799 · « **Reply #10 on:** April 13, 2015, 10:05:44 AM »

I should mention too that I have a FMF gold series pipe. So would a bigger Air Striker be better?

swanitalia · « **Reply #11 on:** April 13, 2015, 10:09:15 AM »

If your getting a new carb, go with a keihin 38mm PWK AS. You won't be disappointed with it.

JesseA420 · « **Reply #12 on:** April 13, 2015, 10:11:10 AM »

http://www.jetsrus.com/carburetor/carb_keihin_PJ_carb_exploded_view_parts.html

countryboy9799 · « **Reply #13 on:** April 13, 2015, 10:17:03 AM »

So with the 38AS would I need a new intake boot or can I stretch the one I have?

Will I need a new throttle cable?

swanitalia · « **Reply #14 on:** April 13, 2015, 10:21:52 AM »

you can stretch your intake boot with some heat. But you will need a new throttle cable, the motion pro part# 01-604.