Carb rebuild

[Andy bauska 27]

So, I did a carb rebuild in my 1993 300. It idled great, but when the throttle was wide open, it wouldn't rev up all the way. My brother thought the needle was out of adjustment. I tried it in several positions, and still no luck. My brother thought it might be a too small jet. (We put the new one the kit came with it) the jets in question are both a 125 size. My brother suggested I swap it back out to the original, because it might be too small. So, I took it apart again tonight and found that they were both a 125. So I swapped them out just because I was down that far. When I put it all back together, it won't idle now, unless it has full choke. So, I need some help, I really hope this forum is better than Hondaatvfourms.net, Nobody will give you the time of day there.

[Fishfiles 17,154]

My first guess would be a  diaphragm problem , crack or  hole in it , misaligned under cover and not sealing , vacuum port to it  clogged 

[Andy bauska 27]

Well, I cleaned the diaphragm with brake clean. Being very careful not to get some on the thin rubber. I only cleaned the hard plastic, and the needle. I only did this because I heard that it might cause my vent line to stop leaking fuel. It still leaks BTW.

 

 

Edited December 3, 2021 by Andy bauska

[Goober 1,547]

fuel coming from vent line?

 

or fuel coming from carb drain line?

[Andy bauska 27]

Which is which? The fuel is coming from the one that hangs down. It attaches on the bowl of the carburetor.

 

[Fishfiles 17,154]

47 minutes ago, Andy bauska said:

Which is which? The fuel is coming from the one that hangs down. It attaches on the bowl of the carburetor.

 

 The vent hose  on bottom on the bottom of the carb  is the over flow tube  , your float / needle valve is sticking or the tank is crudey and specks of rust or dirt is getting in the needle valve causing it to leak 

[Andy bauska 27]

The bowl was pretty junky, So I need to clean it more?

 

[jeepwm69 6,618]

57 minutes ago, Andy bauska said:

The bowl was pretty junky, So I need to clean it more?

 

Yeah, sounds like you still have a dirty carb.

 

Go get you a gallon of Berrymans, open it up, take the carb apart and dunk the body, jets, bowl (don't put in anything rubber/plastic) in the Berrymans and leave it for 24 hours.  Blow everything out with compressed air when you take it out.

 

You'll have to polish the brass seat for the float needle with a qtip or 0000 steel wool to make sure it's perfectly smooth, and get a new needle for the float if you didn't just put a rebuild kit in the carb (which would have come with a new needle).

 

If you're on a super tight budget you can boil the carb body in lemon juice and water (50/50) on a campstove and it does a pretty good job of getting the goop out of carbs, but Berrymans works better.

 

Put an inline filter on the fuel line between the tank and carb.

[Fishfiles 17,154]

1 hour ago, Andy bauska said:

The bowl was pretty junky, So I need to clean it more?

 

If the bowl is " junky " , the junk has to be  coming from the tank , to clean the carb is a waste of time , if you don't clean the tank if the carb was dirty , cause the junk is going to go right back in carb 

[Andy bauska 27]

When I bought the bike, the tank was rusty, I'll throw in a pic. Since I changed the color of the bike, I bought a nice rust free one from a 1996. The carb probably just had residual rust from that tank. I sandblasted the bowl, and cleaned it real good, So I'll see if it runs better. I got the choke thing figured out btw. Not gonna lie, it actually ran pretty good on that. And yes, I do have an inline fuel filter.

[Goober 1,547]

Well actually the overflow tube itself is in the carb bowl. When fuel overtops the top of the tube, fuel will flow out of the bowl drain line. Make sure the overflow tube inside the carb is not cracked. Brass stem in carb bowl 
 

also make sure your bowl drain screw is snug. This will also cause leaking.

 

the carb float lifts the float valve and shuts off fuel flow. If the valve doesn’t seat, fuel will continue to drain into the carb bowl and when bowl is full, fuel will flow out the overflow tube.

A bad float valve, debris or dirty valve seat, worn/cracked float can all cause continuous flow. Below is pix of 93 carb VE90E

 

Edited December 3, 2021 by Goober

[Andy bauska 27]

Thanks. My brother just got home, and we got it running pretty good. It still lacks on the top end tho, Could this be a fuel filter? And what did you think of that tank LOL😂😂

 

Edited December 3, 2021 by Andy bauska