QA03A 86-89 TRX350 carb

[Goober 1,555]

I bought a used QA03A carb off fleabay. The carb appeared to be complete and the price was right. the seller performed an ultrasonic cleaning but it’s still dirty. So I’m posting this thread to more easily show how to clean these things. There are several members here who know these carbs better than me so I’ll look forward to providing them an opportunity to add to the discussion.

 

here’s the disassembled carb—laid out in an exploded view orientation. The main problems with this carb is that the teeny pilot screw oring was missing and the other seals were flat and brittle. Oh yeah the piston was hanging up—i found a piece of glue or something on the side of the piston. Whiped clean and now moves freely 

you can see a pipe cleaner i used to show the enrichment circuit pathway.

 

Edited December 27, 2020 by Goober

[jeepwm69 7,399]

Man I'm glad you posted this!  I got a 350 carb in a few buckets of parts this weekend and the bowl is off, so was wondering what all else might be missing.  Now i have a good pic to use for reference!

[toodeep 1,745]

I always use loctite on the throttle slide screws. I've seen numerous ones come loose over the years. Another thing on these carbs is the adjustment tab for the throttle timing will break off if someone gets too rough with it.

[Goober 1,555]

Here’s a pic especially for @TrxPipUKshowing the starter enrichment circuit pathway. I use pipe cleaners to scrub this channel clean. 
 

Looking the carb over, you can see how the carb channels and vents are routed thru the carb body. I can’t get thru these other channels quite so well. i use dental brushes where i can.
 

The manual says to use compressed air to clear the channels. Always wear chemical goggles when doing this To protect against blowing carb clearer in your eyes!!!
 

thats great advice @toodeepto use loctite on thise piston valve attachment screws. I’ve always dreaded removing them because I don’t want to strip them. Having them back out would be far worse, eh?

 

@jeepwm69Jeep did you find all the parts? i used to have a spare jet holder but gifted it to another member.

[Fishfiles 20,140]

I nominate @goober for Department of Carb Affairs , can I get a second !!! 

[oh400ex 629]

9 minutes ago, Fishfiles said:

I nominate @goober for Department of Carb Affairs , can I get a second !!! 

 

On the condition that we start calling it "goobering a carb" I will agree!

"That carb needs a good Goobering" "Doesn't need a rebuild... just a goobering" etc

[Fishfiles 20,140]

9 minutes ago, oh400ex said:

 

On the condition that we start calling it "goobering a carb" I will agree!

"That carb needs a good Goobering" "Doesn't need a rebuild... just a goobering" etc

How's about we call :

 

 

 

[shadetree 5,770]

and who ya think taught goober ??..lol.

[Fishfiles 20,140]

2 minutes ago, shadetree said:

and who ya think taught goober ??..lol.

 

I think it was me , but I was being humble and modest and not saying nothing , but now that you bring it up  !!! LOL 

[shadetree 5,770]

Just now, Fishfiles said:

 

I think it was me , but I was being humble and modest and not saying nothing , but now that you bring it up  !!! LOL 

yeah...right ...lol...say's the man that never touches a old trx350 !..rofl.

[Fishfiles 20,140]

7 minutes ago, shadetree said:

yeah...right ...lol...say's the man that never touches a old trx350 !..rofl.

Gaw'lee -- Shazzam !!! 

[jeepwm69 7,399]

1 hour ago, Goober said:

 

 

@jeepwm69Jeep did you find all the parts? i used to have a spare jet holder but gifted it to another member.

 

Haven't dug through everything yet.  Got three tubs of parts from a guy, and the carb (or at least most of it) was on top in one of the bins.

[jeepwm69 7,399]

Well, so much for my excitement on the 350 Carb in my bucket o parts.

 

[shadetree 5,770]

1 hour ago, jeepwm69 said:

Well, so much for my excitement on the 350 Carb in my bucket o parts.

 

looks good to me ?..rofl. you need a 350 carb ?.

[jeepwm69 7,399]

Not at the moment.  The 350's are way down the list of projects.  I might not ever get to them at the rate I'm going!

[shadetree 5,770]

2 minutes ago, jeepwm69 said:

Not at the moment.  The 350's are way down the list of projects.  I might not ever get to them at the rate I'm going!

lol..well..holler at me if and when ya need a carb ?, i'm sure i can hook ya up :-).

[jeepwm69 7,399]

Thanks man.  Hopefully I'll get to that point where I can take you up on it!

[Goober 1,555]

Oh that’ll buff out

[shadetree 5,770]

22 hours ago, jeepwm69 said:

Thanks man.  Hopefully I'll get to that point where I can take you up on it!

when ever you swing by to pick up that oil pump ?, just remind me about the carb, i'll toss it to ya no charge :-).

[jeepwm69 7,399]

9 minutes ago, shadetree said:

when ever you swing by to pick up that oil pump ?, just remind me about the carb, i'll toss it to ya no charge :-).

How about I just drop off the whole 350 and you can install the carb on it after you rebuild it!  🤡

 

Seriously though, that's super generous of you on the carb.  I have two 350's that I intend to rebuild at some point.  Hoping I won't have to buy much other than wear parts on them with all the carcasses I have around.

 

 

[shadetree 5,770]

4 minutes ago, jeepwm69 said:

How about I just drop off the whole 350 and you can install the carb on it after you rebuild it!  🤡

 

Seriously though, that's super generous of you on the carb.  I have two 350's that I intend to rebuild at some point.  Hoping I won't have to buy much other than wear parts on them with all the carcasses I have around.

 

 

if ya want to drop if off ?, you better be doing an oem build ?..cuz i dont mix and match parts !..lol. parts are getting hard to find today !. i can make it run again..but i can't make it look pretty !..lol. you furnish the parts ( gaskets and such ), i'll build it..they will come !..lol.

[shadetree 5,770]

@jeepwm69 we take of our own brother !.

[jeepwm69 7,399]

27 minutes ago, shadetree said:

if ya want to drop if off ?, you better be doing an oem build ?..cuz i dont mix and match parts !..lol. parts are getting hard to find today !. i can make it run again..but i can't make it look pretty !..lol. you furnish the parts ( gaskets and such ), i'll build it..they will come !..lol.

 

I'm just messing man.  I know you do awesome work, but these are more "I can piece together a beater that runs" machines.  Your OCD would go crazy and I'd make Catfish look like a big spender.

[shadetree 5,770]

30 minutes ago, jeepwm69 said:

 

I'm just messing man.  I know you do awesome work, but these are more "I can piece together a beater that runs" machines.  Your OCD would go crazy and I'd make Catfish look like a big spender.

lol..me..ocd ?..rofl.

[Goober 1,555]

Can anyone recommend a starter jet passage plug? Maybe a motorcycle plug kit or part number? I don’t want to buy another gasket kit when i only need the plugs. They need to be 4mm diameter With a base about 6mm.

 

i got three QA03A carbs on the workbench today. i can easily stand a carb in an old Blue Bunny ice cream tub and spray carb cleaner into it! And cover it! Perfect fit.
 

Here they are all in various states of reassembly. One from a work rig which was running real rough and fouling plugs—i have another work rig in the same shape.
 

what I found is that the choke valves were never replaced by the tech who serviced the machines and rebuilt the carbs 10 years ago. The carbs look great—some brown film in the bowls.

no doubt he was trying to save me money but they foul plugs in 4-6 months with bad valves. So I’m replacing all 35 year old valves. And fuel filters. and cleaning spark plugs.