New member from NZ. 1985 ATC250ES.

[areffernz]

Hello. New to this forum, have recently purchased 1985 ATC250 ES. It's in pretty good condition cost $200 NZ. I have so far fixed brakes front and rear, new front wheel bearings & seals, new reverse cable, front brake cable, replaced handlebars and new hand grips. Biggest issue was running extremely rich at low revs. After taking the carb off probably a dozen times and blowing every passage through with compressor, cleaning all jets I still couldn't cure it, finally figured out the internal air passage in the body of the carb for the pilot jet circuit was partially blocked with something. Gave up on carb in the end and purchased a brand new carb from china to suit a TRX300 quad ( I happen to own one of these quads also ). Carb was a direct bolt on but had to use a TRX300 throttle cable, choke cable doesn't fit either. Bike now runs perfectly. Anyway apparently I need to get my post count up to 10 before I can contribute to main forum topics. Cheers, Mark.

[22R]

Congrats and good price. I bought this 86 Big Red a year ago for 1500. The tank has a dent on each side I would like to remove but it is my 84 year old Dad's bike right now. I also have inherited 84 200s that I am fixing a few things on as well. I need to get my post count up to so enjoy and post some pics of your ride.

22R

[fabiodriven]

Welcome! I just battled a clogged air circuit in one of those carbs recently that drove me bananas!

[coolpool]

That seems like a really cheap 250es, congrats! I'm curious that the efficient carb cleaning that you described didn't fix the problem? In my experience (or lack thereof for a 250es) using arb cleaner and blowing out all passageways usually works. What's different with these carbs that I need to know about in case I run into the same issue? Fabio, any tips?

[areffernz]

Price was good thats for sure, its in average condition but has not had a lot of use I would say, brakes still had plenty of meat etc. I have owned 4 other trikes over the years, an ATC200, a YTM125 two stroke and two YTM200's. I will put a few pictures of bike up soon.

[areffernz]

By the way Fabio how did you manage to clear the blocked air passage in the carb?

[fabiodriven]

Honestly I just had to give it a ridiculous amount of attention with the carb cleaner, the compressed air, but my best tool for the most stubborn carburetors is a single wire bristle from a wire brush being held by mini vise grips. That's a great carburetor tool. I had the carb out and cleaned it no less than four times then rebuilt it on the fifth go and it was still fat on the bottom and wouldn't run right at all. I got really frickin frustrated (like Todd Hoffman) and sat there staring at the bike angrily for a really long time and the wheels were spinning overspeed in my head trying to wrap my mind around this machine and these symptoms. Everything it was doing wrong pointed to the air circuit being clogged, that's what kept going through my mind. It had to be that. That's when I invented the wire brush bristle tool and was determined to fix this carburetor.

If you want to drive yourself insane, try removing and then re-installing an SX carburetor seven times. It is not a good time.

[22R]

I have heard thst ultrasonic cleaners do well on them too

[areffernz]

Thanks for info fabio. I have tried wire brush strand, and gas torch tip cleaners, neither worked. Would like to get it solved as carb is in great condition. I may try drilling out the welch plug on side of carb for this air passage, shouldn't be hard to reseal afterwards.

[fabiodriven]

I completely forgot! I also soaked it in a carburetor dip for like five days.

[areffernz]

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Trying to attach pics, Attempt 1. Sorry appears they came out sideways, looks like I need to hold my phone in landscape position. Gives you a rough idea anyway. Will look into carb dip, never heard of it.

[ps2fixer]

I spy an aftermarket plastic gas tank that looks to be in good shape. That alone should be worth most of the price you paid for the machine. Also, your rear tires on on backwards, you can swap them side to side to reverse the tread.

I've had a bit of issues with the 250es carb too. My dad bought an ultra sonic clean, I should pull the problem carb and send it his way and see how that effects things. My problem was the opposite though, lean on the low end, or maybe an air leak on the intake boot (didn't test for the air leak).

How much was the Chinese 300EX carb? I wonder if that would be an "upgrade" for the 250es even though it's Chinese made.

My other 250es runs great with a cobra exhaust, no clue if it has any other mods, but it seems stock besides the exhaust.

[deejaycee_2000]

Invest in a ultrasonic cleaner, you will never look back, it is 100% worth it!

[areffernz]

Gas tank is original steel in great condition ( no rust ). Having the rear tyres backwards is quite common over here, I think people have the idea that it gives them more traction when using reverse? Doesn't bother me so will leave them like that. I got the chinese carb for $60 NZ including delivery https://www.banggood.com/Carburetor-Cab-for-Honda-TRX-300-FOURTRAX-TRX300-4-Stroke-FW-1988-2000-p-1032854.html?rmmds=myorder&cur_warehouse=CN Hope that link works.
It has worked faultlessly so far.

[ps2fixer]

I never seen logic put to the reversed tires, but I can counter that logic, how often are you driving backwards xD. It would be true though, directional tires work better in one direction and not so well the opposite way.

The only thing I was thinking of was maybe sand riding so it doesn't dig down as fast, but the lugs are not exactly super deep on those tires (I have the same set on a 250es).

Thanks for the link, it's about $40usd, really cheap if the carb is built well. Might have to pick one up in the spring/summer time to toy with.

[areffernz]

I changed the camchain on this yesterday, not what I would call a 5 minute job but camchain rattle has gone, engine nice and quiet now except for slight tick from exhaust tappet. Should be good for another 24 years now.

[fabiodriven]

You can swap out a cam chain but you don't know how to adjust a rocker?! Get outta here!

[areffernz]

Also discovered that previous owner had put some home made wiring in, had battery positive to one terminal of handlebar killswitch and battery negative to other terminal, so when the killswitch was slid to OFF it created a dead short! Amazingly kill switch itself had survived this but heat buildup had caused one of the wires to unsolder itself, lucky really. Anyway have sorted that and kill switch works fine now.

[Gabriel]

You can swap out a cam chain but you don't know how to adjust a rocker?! Get outta here!

I know a guy who can rebuild ANY automatic transmission but could NOT rebuild a small block chevy and get it running to save his life.

[areffernz]

Yeh, a bit slack really must get round to checking valve clearances.