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Weeping petrol on start-up

292 Views 8 Replies 3 Participants Last post by  Easy Rider
I have a 80s Suzuki GSX400F Katana, which generally runs well. At the moment, when starting the engine from cold, I am seeing a small amount of petrol weeping (please see the photos attached). I cannot see any obvious damage around the area to see where the petrol is coming from. Last season, I had no problem in this area, and this has just started as I am preparing the bike for the coming season.
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Has anyone ever had a similar situation, and do you have a fix?
Many thanks in advance.
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It's impossible to see the leak with pictures.

It is not unusual for gaskets to dry out on a 40 year old vehicle and cause some tiny leaks.

In general, that should not really be a problem........IF it doesn't get worse and you don't mind a whiff of gas
odor when starting out cold.

It likely is the gasket around the top of the bowl.
IF you can find the proper gasket, the fix should be fairly easy. Should be able to do it without taking anything off except the bowl.

BUT if you have never dis-assembled a carb before, I strongly suggest that you let a shop do it.

Have you tried to carefully tighten the screws that hold the bowl on ??
The key word is carefully.
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Thanks for the info, Easy Rider—much appreciated. After drying the outside of the bowl last night, and putting the bike on its side stand, it is dry this morning. In 2019, the bike had a complete fuel system rebuild by the previous owner; I saw the documented photographs of the rebuild. Since that time, the bike has only covered around 4,500 miles (ca. 7,242 km), mainly on rural roads. However, the gaskets on the engine do look in rather poor condition. The positioning of the screws holding the bowl, are quite awkward to get at because of the space available, but I will go and see a mechanic friend, to see if he has something. Oh, and I will be careful.(y)
May also be the float level is too high causing fuel to seep from the joint.
May also be the float level is too high causing fuel to seep from the joint.
Good catch.
Or out the overflow.
Thanks for that, @Aussie Steve. I will have to see how easy a fix that would be. Unfortunately, I am not a mechanic and can only do simple repairs.
I'll check to see if the overflow is okay, @Easy Rider. Thanks for the further suggestion.
Setting a float height is not a job for someone who is not familiar with the process. You have to remove the carb then the bowl. Some carbs have the setting with the carb upside down and from the float centre to the carb upper body joint line. Some have the setting without depressing a spring loaded needle tip whilst other have the setting with the carb right way up and from the float base. You will need to find out which yours is.

The method of closing the flow of fuel differs from carb to carb too. You will need to find out which yours is and follow any instructions carefully.

It isnt too hard a job if you are would pay to take lots of pictures with your phone as you go.

There could be another reason for the float level to be excessive and this is either a worn float needle/seat or dirt clogging the float action.

Good luck....oh and sometimes you can dislodge any dirt by tapping the carb close to the float valve assembly without any dismantling. Also a good carb cleaner may work ER likes Gumout....;)
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Also a good carb cleaner may work ER likes Gumout....;)
Actually original Gumout seems hard to find these days.
I like Berrymans B12 Chemtool better.
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