//ArrowChat Code
Results 1 to 6 of 6

Thread: 85 ATC250ES Big Red NC Newbie

  1. #1
    Join Date
    Dec 2018
    Location
    NC
    --
    2

    85 ATC250ES Big Red NC Newbie

    Hi Everyone.When I was growing up we lived on Stratford Rd in Winston-Salem,NC.I can remember seeing brand new Big Red trikes in front of the Honda dealership.I used to dream about those things.Well,here it is 35 years later,and i finally got one.LOL.It's a 1985 model that I picked up at an estate auction.The factory rear tires still had the teets on them,although they were severely dry cracked.It had an exhaust heating issue,as there was plastic damage on the front and right rear fenders.Fortunately,new plastic was purchased in 1994 and it was still in the wrapper.The battery was dead,gas was stale,and it would only run on choke.So I had some work to do.I replaced the rear tires,installed a new battery,rebuilt the carb,replaced the air filter,and changed the fluids.It runs and drives really well.But I am still worried about exhaust heat.What are normal temperatures for an ATV of this size?Here is what I am seeing:

    250 degrees at the spark plug hole
    750 degrees at the header bend
    500 degrees at the bend near the airbox

    No backfiring.It may be a bit cold natured,but after it warms up it runs good.I don't really have enough seat time to tell if it's down on power or not.I installed a Moose Racing carb kit,but I reused the factory jets.(After cleaning them with a torch tip cleaner.)I replaced the needle and float with Honda parts.Should the exhaust temps worry me?Thanks everyone.

    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	1985 Honda Big Red.JPG 
Views:	925 
Size:	2.16 MB 
ID:	256184  

  2. #2
    Join Date
    Mar 2010
    Location
    Slidell, LA
    --
    4,737
    Those aren’t unusual numbers for sitting and idling. That’s an air cooled engine. The only way to keep that motor cool is to drive it.
    Feedback for yaegerb: Click Here

    Need something blasted or polished or both? Send me a PM

  3. #3
    Join Date
    Apr 2012
    Location
    USA
    --
    4,114
    Also worth mentioning, if the engine runs lean (aka carb jet starting to plug) it would generate hotter exhaust and engine temps. Out of the 6 or so 250ES machines I've had, I don't think any had melted plastics, all but one was the 85 model. I suspect the last owner idled it for long periods of time or the carb got too lean and the owner kept riding it anyway (or idled around while being lean).

    Only other machine I've personally owned with melted plastics from exhaust heat that I can recall was a 1985 ATC70, and that's because the front forks were bent in and the front fender slightly touched the head. I've had probably 30+ atcs, most were parts machines though.

    Also, is the exhaust OEM? Aftermarket exhaust lead pipes don't have the heat shield. The cobra on my go to 250es would get my right leg really hot, so I pulled the heat shield off an OEM one and wired it on, it's not a pretty machine so I didn't care about the looks. Also my machine isn't cold blooded at all and I live up in Michigan. Full choke and it's ready to go assuming the carb has gas in it (I turn it off and run the bowl out sometimes).

    Can't say for sure if your machine is lean or maybe has a fuel delivery issue, but I'd check the gas tank out well, ethanol gas (aka modern pump gas) will rust the bottom of the tank when sitting. The bottom part of the petcock comes off and there's a small screen and settlement bulb. Also if you pull the whole petcock out I'm pretty sure there's screens inside the tank too. They don't always come out nicely, so I wouldn't pull it unless you're willing to buy a replacement encase there's issues with it (broken plastic riser or damaged screens, etc).

    As far as lean vs rich, a good indication is to pull the spark plug and check what color it is. Charcoal black is way too rich, lots of white powder is too lean, a light brown thin powder is just right. Also be mindful different throttle positions uses different circuits in the carb, so idle might be perfect, but wide open could be lean/rich. Also the fuel tank cap can fail to vent which would cause a lean condition over time too (my 250sx has that issue currently).

    Also grab the service manual from http://www.oscarmayer.net/atc/manuals/ there's so much info contained in there, it will help with just about any issue you run into if you know where to look.

    Anyway, good luck with the project, great looking machine.

  4. #4
    Join Date
    Dec 2012
    Location
    Vancouver Island, B.C., Canada
    --
    812
    What kind of tires are those you put on?
    1985 Honda ATC 250ES
    1985 Honda ATC 250SX
    1984 Honda ATC 200M
    1983 Honda ATC 200
    1984 Honda ATC 110

  5. #5
    Join Date
    May 2016
    Location
    OH Canada
    --
    1,102
    Welcome to the site.

    Nice score!!!
    -------------------------------------------------------------------------------------------------------------------------------------------------------------------

    '83 200X

    Chicks love guys that ride trikes

  6. #6
    Join Date
    Dec 2018
    Location
    NC
    --
    2
    Thanks guys.I put Kenda Pathfinder tires on it.They seemed to be the best mix of quality and price.I replaced the complete shutoff valve and filter assembly because it was leaking,so I should have good fuel flow.I'll check the plug after I ride it a bit more,to see what color it is.

//ArrowChat Integreation Code //