KLX400 first start in 3 years-Carb Rebuild?

I just bought a KLX400S that hasn't been started in 3 years. It had 3-4 year old gas in it when I picked it up. I have the tank off cleaning old gas out now and was wondering if I need to do a full carb rebuild or maybe just flush it out? It is the stock 36mm S carb, not the FCR. Also instead of rebuilding this carb, if someone has a stock S carb that is ready to go shoot me an PM I'll buy it. 

 

Thanks Nick

Install the JD jetting kit and do the 3x3 mod.

Let me preface this by saying I'm fairly new to the motorcycle world but have been working on other motors since a kid. I just finished a carb rebuild on an 89 Yamaha xt600. The bike was also sitting for a few years with about a half tank of bad gas. Apparently the petcock had a tiny leak, allowing gas to have plenty of time to make its way into the carburetor and get everything nice and gunky. Given the fact the bike has been sitting for an extended period of time I think it would be wise to run through the carb, If you have the time to do so. I think at some point you would end up have to rebuild it anyways so mine as well get it done now while your tank is off.

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7 hours ago, 38super said:

Install the JD jetting kit and do the 3x3 mod.

After getting everything pulled apart last night I found the 3x3 mod and jet kit had already been done. It does have an aftermarket pipe as well. 

The previous owner told me that when he last tried to start it gas was coming out of the overflow line or diaphragm up top, which to me would mean the float is sticking. 

My local Suzuki dealer opens up at 10am, I am going to see if they have a carb rebuild kit or maybe I can just purchase some of the gaskets and o-rings separately to try and fire it up today. 

Some times gas goo will cause a sticky float pivot or gum up the float valve seat.  Easy fix, no parts needed (if you're lucky).

This spread sheet data will help you compare current jetting to what others are using in similar riding environments.  Add your data if you'd like but pls don't mess up the spread sheet.  There's been wholesale slaughter of valuable jetting data by either unconscious or deliberate acts.

https://docs.google.com/spreadsheets/d/1HNSB3DrqJqHTInjVDKKS4HNSHZPbdK0ElbfNI5HxuZg/edit?hl=en#gid=1172546203

You can fine tune a carb by float height, high is richer.  Doesn't take much so don't go crazy.

 

Well got it back together and she runs like a champ but has a few issues... first, petcock is bad and I will be ordering the raptor one from the thumpertalk store. Second there is fuel in the oil, which means this carb is still bad. I am looking for a carb that is in good shape ready to go... either stock or fcr... fcr I will obviously a lot more for. Please pm me if you have one. 

59 minutes ago, moparmotel said:

Well got it back together and she runs like a champ but has a few issues... first, petcock is bad and I will be ordering the raptor one from the thumpertalk store. Second there is fuel in the oil, which means this carb is still bad. I am looking for a carb that is in good shape ready to go... either stock or fcr... fcr I will obviously a lot more for. Please pm me if you have one. 

That's not necessarily true. If the petcock failed then there's a good chance the float o ring failed too and let fuel into the motor.


Far cheaper than a new carb :p

Edited by Dramabeats
9 minutes ago, Dramabeats said:

That's not necessarily true. If the petcock failed then there's a good chance the float o ring failed too and let fuel into the motor.


Far cheaper than a new carb :p

Thanks, I just ordered a moose rebuild kit    And raptor petcock from the thumpertalk store and will try replcing that float o ring and put on new petcock. I didn't replace anything today just took apart and cleaned to see if it would even run. 

I would love to order the thumpertalk fcr kit for this bike, it would be perfect for it but can't justify $795. 

I decided to have this carb professionally rebuilt from a shop in town. Although I had the bike running last weekend, I went out to it Tuesday night to fire it up and all the fuel out of the tank ( about a 1/3 of a tank ) had leaked into the cylinder and filled up the air box with fuel. From what I read I have a bad vacuum petcock and bad float O-ring. 

 

My carb rebuild kit and raptor petcock from thumpertalk store will be here today. 

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