ES-SX-350X Carb rebuild Tutoral

[Flyingw]

Now for the linkage side of the carb. Do not install the idle screw yet!!!! The next step is very important but before we make the synchronization adjustment, I want you to rotate the linkage as the cable would ensuring the butterfly and slide linkages rotate freely and return all the way back. I shoot a little silicone lube through the two springs and work it in to the two shafts just as an added measure. If all rotates as it should lets do the synchronization adjustment.

This adjustment is critical to ensure the slide and butterfly move together at the same time. Over time, the tab on the slide linkage will bend up. this is exactly why this adjustment exists. The split plate on the linkage is how you make this adjustment but I will typically bend that slide arm tab down a little so the split plate isn't spread so far.

With a pair of needle nose, bent the tab back down if it bent up too far. With the slide all the way down, spread or pinch the split plate until the split plate just barely touches the slide arm tab. I actually use a loupe to help me see when the two touch. Now rotate the linkage a few times ensuring the linkages rotate and return back all the way and the tab and split plate are still just barely touching. Once this is done, assemble and install the idle adjustment screw but do add some lube to the end of the screw before you install it. Thread the adjustment screw in until it contacts the throttle cable linkage. From this point I usually give it about 2-3 turns so when I do my initial engine start, it will start and fast idle then you can adjust the idle to your desire. I set my idle to 1200-1400 rpms.

Again, I cannot express to you how important this adjustment is to the proper operation of the carb. If the slide and butterfly are not in synch, the motor will do all sorts of funny things like fall on it face when you hit the throttle. Pages 4-12 and 4-13 give you the factory steps to this adjustment and pages 4-14 and 4-15 in the ES manual.

[Flyingw]

Alright, we're rounding 3rd and heading for home....

The last thing to do is install the bowl drain tube and the two vent hoses. The 86 model carbs had this spaghetti mess of vent tubes. I rebuild my carbs with two simple vent tubes. I buy 5/32 vacuum tube from Autozone. For fresh tubes, you will need about 18" of vacuum line. For the bowl drain tube, I cut a length about 10" long and the two vent tubes are about 4" long but you can cut these any length you want. Install the bowl drain tubes and vent tubes.

Well that's it fellas. For me, the next step is to install the carbs on my SX and test them. The last adjustment you may or may not need to do is adjust the pilot screw. The symptom if you DO need to adjust the pilot screw is the motor will fall on its face it you hit the throttle. With a warm motor, choke off from idle hit the throttle. if the motor falls on it face turn the pilot screw IN 1/4 turn at a time. This fattens up the pilot circuit but of all these carbs I've sold, only one guy reported to me that he had to adjust the pilot screw. From sea level to about 2000 feet, it should be good to go.

You guys are free to post away. let me know if you have any questions or is confused about anything. This is the process I've been following and it seems to be working as I've sold about 20 of the ES and SX carbs. Good luck with your rebuild and as I said before, these procedures pretty much apply to any of these 3wheeler carbs you have.

END OF TUTORIAL!!!!!

[atc007]

Well Jim. I have been doing these carbs more decades than I care to remember. All with great results. But you my friend have taken it clean over the top! It is SO cool to see you mix in what you've acquired in the aircraft industry to this! I never heard of that goop. But I will have a tub soon . I have found over the years that I prefer solely. NAPA carb soak for carbs. You MUST remove any and all parts that will be eaten! Rubber,o rings etc. And as you said. Restoring any and ALL little holes in any carb is crucial! Rather glassing them or drill bits ,whatever. It is essential.This tutorial, now available to any and all who want a as new OE Honda carb, serves as a school to even some seasoned techs working in shops! I can't thank you enough for the time this must have taken you. I can only imagine. Consider the deal we were talking about done as a small token of thanx. Email me your ppal if it's all still available. This is 1st class all the way Thanx Jim .

[MRSOUND]

Thanks for the step by step Flyingw! Having a sx & es I WILL be using this tutoral over the winter to rebuild both. Subscribed to the thread first day so I could following along and now have it book marked for later reference! Awesome detail with pics....don't get any better. Thanks again.

[Flyingw]

Thanks guys. That means allot coming form you. What good knowing all of this if others can't benefit from it. As I said, I don't do this to pay bills, I do it for fun. If I had to do this to pay bills, it wouldn't be any fun at all.

Bill, I sent the SX diff home with Filthyhat yesterday simply as a time saver for him but I do have his diff and its in beautiful shape. I just need to give it a fresh coat of paint and rebuild kit and it will be good to go. I want Filthyhat to get his rear end installed and tested before I do anything else. After that then yes, we will do something up.

[Flyingw]

One note to the rebuild of these QA series carbs. Bill mentioned above those carb soak chemicals. That chemical is very nasty stuff. It works very well but is pretty aggressive. On the three parts carbs I bought, I had to remove the slide actuator and butterfly shafts from the carbs. What I learned on these is there are two felt seals in the body of the carbs. Their job is to provide a debris seal for crap working its way down the shaft hole. I'm pretty sure the carb dip will dissolve the felt. I had no idea they were in there until I started seeing bits of felt in my blast cabinet. The air pressure had knocked the seals out. Luckily I only lost two seals so I cannibalized both seals from this carb and replaced them.

As for the assembly of the 350X carbs, the variation of the assembly process should have included the different idle adjustment screw assembly and the choke valve and lever assembly but those are pretty self explanatory. One other thing to note, the 350X carb is considered an upgrade to the ES/SX motors. They do fit just the same as the ES/SX carbs however, you can omit the X choke valve and lever and install the stock ES/SX choke valve and use it the same way it was designed for and that is with the choke cable. It screws in all the same. If fact I have a 350X carb to test along with three other ES carbs. The X carbs runs very well on the ES/SX motors with a little tweaking to the jetting.

[atc007]

Yes indeed. The soak will eat the felt. It will also ruin/eat,all plastic bushings. I soak only where it's safe/or completely disassemble the throttles ( Like you said. they all need synced when they're done anyhow. I have seen one TRX 250X and one TRX 300EX actually break the idle adjustment arm clean off before! These are very serious springs. I won't get into how nice and soft you can make your throttle push by playing with the spring. Better to live with them stiff

[Flyingw]

After fussing with these three carbs, I have figured out how the two connected shafts have to go back in. The butterfly plate can be a big pain to get back in even though its symmetrically cut out, the way its worn dictates which way its tuned and flipped to set it back in the right way and is easily damaged using the wrong tool to grab it with. But now I know. I thought about adding that to this but trying to convey how I have to flicker the shaft to set the butterfly in to its groove might be a little difficult but I figure most guys won't mess with that anyway.

[Flyingw]

Oh, and since the shafts were vacated from the bodies, I didn't bother masking anything off for bead blasting. I just made sure to not hold the gun nozzle over any of the sensitive holes. All the holes blew through. The only thing I couldn't get out was the nozzle tube under the startup jet. Its a very mild interference fit and couldn't figure what I could stick in there and grab the tube to pull it out without damaging it.

[Big G]

This is great Flyingw! Awesome to see you took the time to put this thread together. I'm sure it was no easy task - especially with all the photos and diagrams you included. I'll be referring to it in the future because unfortunately I have the dreaded cold start issue with my '85 250ES. Actually, on second thought, I think I'll just send it to you and have it done right

[Flyingw]

Copy that Big G. I can take care of it.

[Flyingw]

Tonight I tested five carbs, four 85 ES carbs and one 85 350X carb. All but one checked out. The one that didn't run to my satisfaction is the carb I got from Colorado. If you recall, that's the one I put the SX butterfly plate in to. The carb appears to be running lean. The motor has a slight pop on deceleration and at idle the motor seems to be running hot. I'm going to pull the carb apart and go back through it but I'm find myself wondering if the butterfly plate has anything to do with it. If I had an ES butterfly plate I'd be inclined to drop it in there and see if it runs the same but I am out of those.

[Dirtcrasher]

Great work as always Jim!!

Glad to have you in the "trike" industry.....

[dougspcs]

One thing for sure, I'm keeping this thread link handy..

We will be referring back to it for years to come..every time a newb asks why their machine is running like crap!!

A great piece of reference material that is unarguably the bench mark to aspire to..if yours doesn't even come close to looking like this..go back and do it again!! Until then, no more questions!!

Carb threads are getting for me what oil threads are to Fabio!

[atc007]

To be fair though. On a Mikuni/Yamaha/Suzuki. All you need are .A. Parts that are still serviceable. And B. Pilot and main circuits that are still open. That's it lol. These Keihins are arguably the most complicated 3 wheeler carbs there were. A newb asking a carb question would be WAAAYYYYY Overwhelmed looking at this thread when all he needs to do is blow out the pilot and main air and fuel circuits and ride lol...