85 atc 250r problems running

[SteveCZ28]

I recently bought a 85 250r. It starts great and idles fine. But when u get out on it to actually ride it, it likes to bog and not actually hit the powerband. It sounds like its loading up when you try to give it gas and it has a solid smoke trail after the trike. No matter what I do with the air screw on the side it doesn't make it run any better. I really dont know where to start. The carb is clean and dirt free. I checked the jets and their clean also. Im just needing some help as to where to start looking on this beast. It is 100% stock with exception of a open k&n intake and filter.any info or ideas would be greatly appreciated

[stevensj13]

You are running a bit lean. Any modification to the air flow or exhaust flow will require a change in jetting, especially an Open K&N intake and filter. Go the the closest local Honda dealer and buy some new main jets, The size you want depends on the size you have. I would recommend buying a few jets, and only go up one at a time until you find the perfect one.

[KASEY]

if your still running the stock silencer that might be your problem,, after years of use they get all gummed up with oil,,, and a stock pipe has a lining in it that will also get oil soaked,,, how the hell someone can say your running lean from your post is just plain lame,,, sounds like you need to look at the plug,, what oil ratio are you running? the air screw is only for air fuel at idle so it won't make a difference ,,, if your all stock and have oily goo running out of the back of the pipe,,, maybe you could have the pipe and silencer cleaned at a radiator shop, it will make it run like new and get rid of the trail of smoke,,, mix up some gas at 32 to 1 and ride,,,,,,

[SteveCZ28]

Stock jetting as far as I know. I don't know how to check to see what jets I have. I thought it was running rich due ti the thick smoke trail. So im not believing the running lean post at all.I believe I have it mixed at 20:1 as that was what the sticker on the bike says and that's also a recommended mixture for my banshee also. Yes it still has the stock pipe and sole certain. I noticed the baffle is still in the silencer. I might pop that out and look for sludge in there.

[SteveCZ28]

Also for the mixture for actual riding do I adjust the clip on the needle being as the air screw is pretty much for idle? I've never really messed with the jetting of carbs or needle clip settings. I basically know how to tear down a carb to clean it.

[KASEY]

you will NOT have to rejet a stock machine with a stock pipe and sliencer if you put a k&n filter on,,,,,, wheres tha extra air going to go???? there is no reason to run 20 to 1 ,,, either... if your going to keep the stock exhaust i suggest getting it cleaned out ,, at that high of oil ratio you will never get rid of the smoke trail... and the inside of the pipe and silencer will be soaked with oil......

[Vealmonkey]

Kaseys advice is really good and I would highly recommend listening to what he says. But you may also want to check your 2 stroke oil. Some 2 stroke oil makers have a recommended mix ratio that is different than what the honda recommends for their brand of 2 stroke oil. You may want to check what the oil maker may be recommending and make sure it doesn't conflict with what honda recommends. If the maker recommends a certain mix, than I would seriously consider running what they recommend. And jets generally have thier number sizes on them somewhere, so you should be able to rear what your slow speed jet and high speed jet sizes are. If you are sight challenged like some of us older members, remember your magnifying glass! LOL Smoke is caused by oil Too much of an oil mixture will cause excessive smoke even though your jetting for your carb may be right on the money. A dirty air filter can cause rich running condition as it restricts proper airflow. All these things should give you several possible causes or conditions that you will want to check into. And check your sparkplug. That will definitely give you a good insight as to wether or not you trike is running lean or rich. Proper plug color should be a tan or brown. White color would be showing lean and a dark grey to flat black would indicate a rich condition. A shiney black plug would show that you were having other problems, but your plug is burning off your 2 stroke oil, hence the bug screen. LOL I would be way more concerned if my 2 stroke had no cloud behind it at all then I would by a nice thick cloud. LOL No 2 stroke oil is way worse than excessive in my book.

[SteveCZ28]

Lol ok. So how do I get it to run better? And what fuel ratio do u reccomend?

[SteveCZ28]

I want a good ratio that I can use in both my r and my banshee just to keep the mixing of fuel easier to do instead of having different mixtures for different bikes

[SteveCZ28]

ok i got off work, and checked my r out.....checked the silencer. it does not have thick oilly residue, or sludge or anything like that. a very light film of oil tho for obvious reasons. took the baffle/spark arrestor out, and same deal no sludge, not wet. is dry and light oil film...checked the spark plug. it is a flat black color. not wet at all.

[falloutboy]

mix up some gas at 32 to 1 and ride,,,,,,

How does that saying go? "32 is the new 20"

20:1 using most of todays oil is just too thick.

On the side of your main jet (one in the center, hangs down lowest in float bowl) there is a number. If it's the stock 85 carb (round slide) it should be a 142.

For jetting, start here: Carb Jetting 101 Terms Tips and Jetting Theory

[ceaserthethird]

You don't know the history of the 250r, so I would recommend New -

Air filter / Wash & Clean, Spark plug, transmission flush and fill, radiator flush and fill, check compression must be over 170psi, check your reeds if worn replace them.

Report back.

32.1 mix ratio / 92 octane

Spark plug - NGK BR8ES

[SteveCZ28]

Air filter is new already. Ill grab a plug. How much oil does it take for the tranny as their isn't a dipstick? Ill get hold of a compression tester and check on the reeds ill update when I get this stuff done

[jb2wheels]

OP - your R sounds just like mine. I was hoping you resolved it so I could have a clue. I hope you get it fixed soon...

Mine is stock except for a clean and oiled UNI air filter. Starts great. Idles fine with the idle speed screw turned way in. Bogs and smokes like a freight train right about when the powerband hits. It does this with or without the air filter and with or without the sliencer.

My crank seals are good. Carb cleaned and rebuilt.

I'm moving on to ignition troubleshooting (swaptronics) - stator, CDI box, coil.

Might even be a head gasket but I'm not getting any bubbles in the coolant while running and I don't want to pull the head. That will be last resort.

My info:
Maxima 927 oil, 32:1 - fresh batch with fresh gas.
New plug NGK BR9ES
Clean and oiled Uni filter.
Stock exhaust.
Stock carb with stock size jets - 142 main, needle on 2nd groove from top.
Carb cleaned and then rebuilt with carb kit during troubleshooting with no change.
Stator resistance = 130 ohms, spec is 50-250 but I've been told anything under 150 is suspect.
Coil and pulser ohmed OK.
Crank seals good - LH does not leak when sprayed with carb cleaner while running, I replaced the RH seal but the original was not leaking.
Compression 165 PSI - I'd like to see more but that should not be causing my issues.

[SteveCZ28]

dug into this a little yesterday. checked, flushed coolant...bought a compression tester and checked i have about 167psi for compression. havent checked reeds yet. and didnt change oil as i dont know how much to put in. will tear intot he reeds and find out what my jets are this weekend