Carb Experts!!!!!!

[Flyingw]

I am in the process of rebuilding a few carbs for the SX/ES but one of the carbs is from an 85 TRX250. Its the same basic carb as the SX/ES carbs with one differance, the hole for the primary jet is blocked and not threaded for the jet. This TRX carb is a QA04AC. The jets called out for this are almost the same and everything else is the same. A couple weeks ago, I took a call from one of our guys who rebuilt a QA04A and put an SX carb kit in to it for his SX and it wouldn't run for crap so i thought I would try to do the same thing to see if I had the same result. I haven't assembled it yet but can anybody tell me why on this carb for the TRX would the primary hole blocked off and not used?

The pic showing the threaded hole is the SX carb and the non-threaded hole is the TRX carb.

[Flyingw]

Well I assembled the carb with the SX carb kit and installed it. I had the same exact results as Larry did. It starts up and idles fine but if I hit the throttle, it falls on its face but if I ease through the throttle, it will rev up. The motors on the TRX this came off of is basically the same motor as the SX/ES. I dont get it.

[shortline10]

I just rebuilt one of those trx carbs a couple weeks ago and remember a rubber plug in that hole . Are you sure its blocked off and not sucking fuel threw their ?

[Flyingw]

There was no rubber plug when I tore it apart nor could I blow air through that hole but for chits and grins, I'll stick a rubber plug in and try it again.

[Flyingw]

Hey Shortline, do you have the factory manual for the 85 TRX250? I'm wondering it it calls out for that hole to be plugged. The fiche is hard to tell but item 24 appears to be a plug/cap but cant tell for sure. I'm looking for a picture out of the book that shows that hole blocked. I have an 09A carb that's rebuildable but if I cant get the 04A going then I wont waste my time.

[Flyingw]

I found the manual and now I'm really confused. The manual confirms a QA04A carb but it shows it as having a primary jet not a blanked off hole. WTF over!!!!!!

[Flyingw]

The book also doesn't list the QA09A carb for the 87 TRX 250.

[atc007]

AS far as I know,,they come w a black rubber plug. I've never switched them back and forth that I remember. You said it is a 85 carb off the tRX,they DEF changed them 86 and 87,but you know that. Every one I remember tearing apart had a plug. I have a customers 85 here at the moment ,w the engine out,,so I could peak in it Real quick for ya if you need me to check anything out . I think all you need is a plug.

[Flyingw]

would you mind doing that. I'm curious to know whether its jetted or plugged.

[atc007]

Yep,you need a plug,,it's flooding itself. And yes,,of course,,all 4 screws were stripped! Nothing a pair of vise grips didn't fix quick.

[Flyingw]

Thanks very much. I will install the plug and reinstall it. Yikes, that carb's a mess. This weekend I had 9 carbs to rebuild 01, 02, 04, and 09. Of the 9, I have sucessfully rebuilt 4 of them with 2 more to do today and this includes the 04A. A couple of them were worse than that one but the bead blaster works wonders on the corroded bodies. I just finished putting my latest SX build up on the stool. I'm pulling the carb with one other to rebuild to throw in to the pool. I already have one set aside for this build. Thanks very much for checking on this.

[atc007]

LOL,,my friend,,in OUR climate,,,,THIS carb looks as new!! I am NOT kidding. No crud in the bowl,,nothing. I will make it look like yours if he ever pops for an engine. But I see much worse from abusive/neglectful customers. But then again,,They don't bring them here because they run great! They bring them after they won't move any longer. I pushed PM for years,,some took to it ,most didn't.

[Flyingw]

I hear ya on the PM. People fail to realize the costs of not taking care of their machines.

[shortline10]

Nice pic's Bill Hope it works out for ya Jim .

[Flyingw]

I have 1 plug luckly so I'll let you know how I make out later. Right now I'm working on an 01 and an 02.