1985 ATC 250r EATS gas...

[Afrothunderkat]

Took my trike on a 3-4 hour ride today, and I ran out of gas. Twice.

First time, ran out of gas from full tank to 1/4 in 3 hours. Second time was 1/4 tank refill and it ran out in 30 minutes. Carb does not leak, and the jets are stock. I was ridding with my buddy on another 85 250r, he had half a tank when mine was empty. We both ride aggressive and his trike is much more explosive than mine. Why do I go through so much gas?

Stock jetting THAT rich? My plug is black. Im running 32:1.

For engine mods, trike has boysen reeds and a FMF full system

[dougspcs]

Not having the same experience as other members particularly on the 2 strokes I can't give the direct answer you are asking for..then again I don't think anyone can.

But then the answer is in your question I believe..stock jetting on a modded engine setup, and your plug is giving you the clue.

Time to start jetting experiments. I'm sure there are a few in here with some main jet numbers to start with.

I guess you rather run rich than lean..lots more troubles than running out of gas come of that.

Good luck with your experimenting!

[El Camexican]

Sounds like you're running rich and/or may need new rings, but still 2 hours out of a tank running hard seems ok. Keep in mind these trikes were made with closed circuit racing in mind, not a day long enduros, the range is likely not that great on a stock tank. I don't know the 250R well (haven't ridden one since 1986) or how large your tank is, but I'm guessing there are guys on here that get worse mileage than you are. BTW, your buddy with the better performing trike is likely jetted closer to right than you are and like I mentioned, may have a better sealing engine. Time for a compression test and then if its good, a muffler packing and some jet tuning. I know you said your carb is not leaking, but you want to be sure the ends of the drain lines are dry. You may be leaking intermittently if you have a bad needle/seat. Lots of easy things to check. Have fun.

[falloutboy]

3-4 hours of riding on the dunes is about what I get on my R before I have to refuel. I'm running a DG pipe with a fmf silencer and a K&N in the air box, lid off. When you open these things up to breath, they get thirsty.

[3wheelrider]

Lots of factors & variables involved. Riding conditions/terrain/mods/tuning/wear/rider -ect. I always go thru 4 gallons in about 5-6 hrs of almost non stop riding.
('85 ATC 250R).
^^^^^^^^EL Camexican^^^^^^^^good advice/tips

[Marty]

When I had my 1985 ATC 250R it had 190lbs of compression, stock carb, ESR pipe, carbontech HT reeds, and if I got 2 hours of seat time at Glamis dunes I was happy. But ATC ate fuel but it didn't help it had paddles and I was 220lbs and in sand and my 1985 ATC 250R was dyno tuned>

[Super350]

so im the buddy...just throwing it in to give a better idea. My trike isnt on steriods or anything but is fully piped, .20 over, v-force 3's and duncan racing carb.
Something is def going on with afro's b/c when hes about out i have 1/3 of a tank or so left and mine likes to piss out the overflow TOO!

I think hes not quite tuned in but I also think it has a lot to do with the stock 85 carb (round slide). Thats alot of gass difference, and we are about the same weight. Can anybody chime in that has replaced theirs from round to flat? Any noticable difference in gas consumption?

[2fiftyR]

My 85 250R is a very thirsty beast. Pound for pound much worse than my 454 powered chevy 3500HD. I can get about 2hrs out of a tank.

[RIDE-RED 250r]

so im the buddy...just throwing it in to give a better idea. My trike isnt on steriods or anything but is fully piped, .20 over, v-force 3's and duncan racing carb.
Something is def going on with afro's b/c when hes about out i have 1/3 of a tank or so left and mine likes to piss out the overflow TOO!

I think hes not quite tuned in but I also think it has a lot to do with the stock 85 carb (round slide). Thats alot of gass difference, and we are about the same weight. Can anybody chime in that has replaced theirs from round to flat? Any noticable difference in gas consumption?

Well, before I did my 350 cyl kit I was running a stock cylinder that was .050" over. No porting. Aftermarket reeds, torque spacer, high comp head gasket, 38mm PWK/AS carb, full FMF Fatty exhuast.

I ride seasonal gravel roads, long straights and sweeping curves. I spend quite a bit of time cruising in 5th or 6th playing around hitting the pipe often. That setup would get me 25-35 mpg. I only know because I ride with some 4x4 quads that have speedo/odos and was curious to know. It translated to roughly 2 or more gallons burned in about 3-4 hours actual seat time depending on how addicted to the happy lever I would be on any given day and how fast we are riding.

Since going to the mid-top ported 350 with most of that appropriate intake/exhaust components (bout the only thing I'm lacking is boring my 38mm carb to 40.5) my MPG has gone down noticeably. I seem to be doing right around 20 mpg give or take.

If you have a worn topend that could cause excessive fuel consumption....

I concur with all of the previous advice posted.

It really does depend on the rider and his/her style, gearing, rider weight. So many variables. All you can really do is make sure everything is up to snuff with your engine and jetting and let the chips all where they may.