Fuel Filter replacment Help. New

[xamnay]

Hi there

My name is Yannick and i am new to motorcycles along with their repair

My 1980 xs400 is having trouble starting and if i can get it started (usually with a push start) the engine dies after i pull the clutch in or stop pulling on the throttle.

After consulting my owners manual i figure the bike is being starved of fuel because of a clogged fuel filter.

Could any one walk me through the replacement or cleaning of the fuel filter? i don't even know what to buy right now i'm looking at this site for parts http://www.mikesxs.net/products-112.html (if you scroll down to the bottom there are three different types of fuel filters. I'm not sure witch one to buy)

The manual is not vary clear about how to replace the fuel filter its about a three paragraph segment that basically just says. "replace and clean the fuel filter"

Hope you guys can help.

-Yannick

 

[JARichmond]

You can remove it from the petcock and rinse it with a petroleum solvent and a cloth. I would also highly recommend installing an inline fuel filter. I've never seen an OEM petcock filter replacement, so try to keep the one you have. Mine has a hole at the bottom so I had to install an inline. Inspect your filter carefully as anything larger than half a millimeter running past your filter can ruin your carb jets.

 

[xamnay]

thanks for the reply Richmond. What is an inline fuel filter and is the installation challenging?

 

[Lou Ranger]

thanks for the reply Richmond. What is an inline fuel filter and is the installation challenging?

Hi. Welcome to the Forum.
Here is a good "how-to" which was put up by another new rider. I followed it with success. I bought the filter from the local bike shop (less than $3) and a length of spare line from the auto-supply store (less than $1).
http://www.xs400.com/forum/showthread.php?t=7574

 

[xamnay]

doesn't an inline fuel filter kinda slowdown the flow of fuel causing it to heat up and evaporate. creating less performance?

 

[HoughMade]

doesn't an inline fuel filter kinda slowdown the flow of fuel causing it to heat up and evaporate. creating less performance?

Simple answer "no".

If the filter flows enough fuel...and even those made for law mowers can support an engine up to 80hp, it will be no problem.

My "Mr. Simple" test is this- unhook the fuel line from the carbs- see how long it takes to drain a quart, or a gallon or the tank. Is it even within the realm of possibility to use that much gas when riding? For instance, does it take 5 minutes (or 10) to drain a gallon? Can you use a gallon riding in that amount of time? No. That means the flow is adequate.

Heat up? Don't route the fuel line under the headers- and why would you- and it will be fine.

 

[XSLeo]

It sounds more like your carbs need cleaning. Hard to start and poor idling indicate dirty enrichener and idle circuits in the carbs.
I work on XS650's more than the XS400 but the BS34 carbs used on both are very much alike. I use this guide to work on the carbs.
www.amckayltd.com/carbguide.pdf
Your carb specs will be different than those in the carb guide but the tear down cleaning and tuning will apply.
When you tear down your carbs write down all the numbers you find on all the brass parts. The good folks on here will supply the adjustment specs, like float height and turns out on the idle mixture screws.
The petcocks can be removed, torn down and cleaned. There are small passages inside that can get plugged. There is a rubber disc with holes. It gets worn, you can flip it over and have a good side but if hard flipping might not help.
Leo

 

[JARichmond]

XSLeo has got a great point. Carbs are more likely the part that will cause fuel starvation as there are many more things that can go wrong or get dirty. In sharp contrast, however, here is a walkthrough to inspection/repairing your petcock.
http://www.xs400.com/forum/showthread.php?t=8033&highlight=leaky
If your carbs are off for cleaning and inspection, it won't hurt to do an inspection of your petcock (provided you don't break anything).