**1985 Honda ATC 250R throttle and carb issues**

[PittsburghPete]

First off...Hi everyone! I'm relatively new to the forum and am already learning so much. I am also very excited about the upcoming 2014 Trikefest!! Can't Wait!! Now with my current issue...I recently jumped onto my '85 Honda ATC 250R only to find the throttle response was groggy. At the top of every new gear it would sputter and if I have it more gas it would then correct itself until I would then climb into the next gear and the same thing would happen until I gave it more gas. It is a thumb throttle, not a twist throttle on there. So....like so many times in the past as I began to search for the remedy my ADD kicked in and next thing I know I'm installing a new handle bar, new grips, bar ends etc. Well as I was taking off the old handle bar and putting the new one on I removed the gas tank and traced the throttle cable back to the lid of my carb. Right where the cable enters the carb lid was a 90 degree metal tub...you know what I'm referring to and it was broken in half..the throttle still responds but that coupler...some come straight up and out..some make a 90 debree and some make a 45 degree. Well...I take that out...remove the slide and start looking at the needle...the needle is a 28V..the ring at the top is half way down those 4 grooves and the needle is all marked up...rub-like marks about half an inch above the bottom tip of the needle. So I ordered the OEM throttle cable...just got it today..when you hook the throttle cable up to the lid of the carb...I threaded the screw device into and through the lid and then secured the small nut onto the screw on the underside of the carb lid after I screwed it all the way in and down...made sure the needle sat down and straight...made sure the large spring inside lined up perfect from top to bottom and then tightened the carb lid. Ran the cable along the main stem of the frame underneath the gas tank and up through the handle bars and over to my thumb throttle on the right side of my handle bars...dusted off my hands..put my plastics back on..hooked the fuel line back up, opened the choke and fired her up!! Let her run with the choke on for about 20 seconds and then closed the choke and took her for some laps back behind my warehouse. Here's my problems now: The throttle has a lot of play now before it tightens when you push on the thumb throttle...I can move it back and forth a lot before I push it forward and it tightens as I excelerate....I can't remember how to fix that...I unthreaded the large screw that screws in directly to the thumb throttle casing and it still doesn't tighten nearly enough; And I still have throttle response problems....meaning...start off in first gear...groggy until I give it a lot of gas...then switch into second gear...groggy until I give it a lot more power..same with third and I didn't go further after that. I'm dumb founded at this moment....I NEED THIS THING TO SING!!!

[yaegerb]

What's your budget? IMO, I would ditch the OEM (I assume its OEM, you never stated) and purchase a 38MM air striker carb.

Link to 38MM A/S on ebay: http://www.ebay.com/itm/Keihin-38mm-...e96946&vxp=mtr

If that doesn't work for your budget then I would pull the carb, clean it/rebuild and ensure that your petcock is clean and free of debris and check for airleaks around the rubber intake. You should have 1/8-1/4 of free play in your thumb throttle. If its more than that then you may have the wrong throttle cable or its improperly installed.

[wonderboy]

First, download the service manual: http://www.kb0nly.info/ATC/index.php?dir=ATC250R%2F

I think you just need to unscrew the throttle cable some from the top of the carb. Use the jamb nut to lock it, but unscrew it some. Start with the adjustment screw at the thumb throttle in most of the way and unscrew the cable adjuster somewhat on the top of the carb. Then, as you test the throttle, back out the adjuster at the thumb throttle until you feel the slop go away.

EDIT: check out page 2-10 of the service manual.

[PittsburghPete]

If I install the new 38MM air striker carb will I have to adjust the jetting (I have a fatty gold FMF on their currently) or reconfigure my air box?

[PittsburghPete]

Thanks...I just looked at pg. 2-10 in the manual...the inside of the thumb throttle casing looks nothing like the inside of mine....the mechanism inside the manual thumb throttle casing is much bigger...mine looks the same on the outside but inside its just a lever with a spring and a nut holding it tight and it retracts all the way back to the screw poking thru with the throttle cable inside it.

[yaegerb]

If I install the new 38MM air striker carb will I have to adjust the jetting (I have a fatty gold FMF on their currently) or reconfigure my air box?

Adjust jetting, yes. No worries though, I have the same setup you do and the same year bike. If you go the 38MM route send me a PM when you are ready and I will give you my specs to dial it in perfectly. You do not have to reconfigure the airbox. All you have to do is squirt some WD-40 on the rear bell of the carb and heat the intake boot up (if you can) and slide the intake over the back of the carb. Other than that its painless.