Fuel leak from #4 carb

[John]

The hex on the seat assembly is 10mm. You may be able to snake a small wrench in there. If not, then pull the pin, and put a socket on it.

[pit-fighter]

I've got another set of carbs i bought off ebay...they are supose to be good...they look good but im no expert...geuss i'll put those on the bike today.

[pit-fighter]

Well i put another set of carbs on my bike...but cant get it to idle and it only smooths out around 3-4 thousand rpms...Is there any adjustments that i need to make when putting carbs off another bike onto mine?..these carbs are a set i got off ebay..that was supose to have been taken off a good running bike.

I put the original carbs back on the bike and it runs good but still leaks gas out where the butterfly is on the #4 carb...its acts like the float is not working and overflowing the carb with fuel.

[pit-fighter]

I ask the guy on ebay why the carbs dont work like he said they would...he told me that the carbs work fine for him..that i must live at a different altitude than he does ..and if thats the case then i would need to tune the carbs to the altitude where i live..he's in new mexico and im in tennesse...does this sound right to you guys?

[TopCatGr58]

Hmmmm.....could be e e e e?

Hey there Pit,

If he's at a lower elevation, and if you're at a fairly higher one in the mountains of Tenn., then it possibly could be set too rich?

Also depends on what mods were on his bike as well, and IF he had it tuned for those mods, like aftermarket exhaust and intakes/filters, both breath better and can require increased jetting to prevent an overly lean condition. Then you put it on your bike....can't remember what if any mods you have? If none, then it could be jetted too rich just for that, along with the increased altitude which thins the air density and can make it even richer!?

Also, what style carbs did you get, the same 78-79 style, or the later 80-81? You could try turning the pilot screws in a turn on each carb to see if that would help lean out the lower end throttle range. Might need to pull the bowls and inspect the pilot jets to see what size and style they are. Also, you probably need to synchronize the carbs to your bike as well.

Lots to learn and do, sorry they aren't Plug and Play!
T.C.

[pit-fighter]

These are 78-79 style carbs same as mine...I tried adjusting the pilot screw Didn't seem to change anything...there's no mods done to my bike...dont know about the bike the carbs came from...shouldn't the bike at least idle even if the fuel air mixture is off and the carbs are out of sync?

[TopCatGr58]

Welcome to carb hell!

Hey Pit,

There are many examples of folks with problems in idling and poor performance, just from the carbs NOT in synch, or the pilot screws set wrong. But more often it's been the WRONG jets, specifically the Pilot jets, as has been mentioned the K&L series are notorious for being incorrect!

Have you read the Carb Tech Tips? With your new set, you can do a bench synch to get them close. Next, you need to pull the bowls, and check for the presence of the pilot jet tower plug, usually a large headed screw, but may be rubber plugs! While you're in there, wouldn't hurt to pull the pilot jets to verify what size, and IF they have the required holes in their sides. Your old carbs seem to work, so you may be able to swap it's pilot jets into the new carbs IF you find them wrong! Also check to see what the float heights are, they may also be set too rich!?

Then turn the pilot screws all the way down to a "GENTLE" seating, then back them out ~1 & 1/2 turns each. This should get you fairly close. Then you should be able to mount them on the bike and have it run! You'll still want to vacuum synch them.
Have fun!!
T.C.

[pit-fighter]

Hi topcat

What you said got me thinking...my old carbs do work good ..just the #4 carbs leaks and the leak seems to be coming throught the gasket on the seat assembly that holds the float needle...So i took the seat assembly,gasket,float needle and float out of the #4 carb i got on ebay and put them in mine...put it all back together it started right up...no leaks and runs like a champ..

Thanks john and topcat for all your help.
Some good info in the tech tip on this site.