85 250r runs like crap

[Mr.Atc]

my 85 250r is running so terrible i dont want to even ride it. i put an aftermarket bills pipe on it and its jetted perfect the plug is golden brown. The carb was leaking out the overflow until i took it apart and cleaned it. the only time it wants to run good is when im in 5th or 6th gear tapped. low end it has no power. it has good compression. im wondering if maybe one of the reeds broke? maybe the float is out of adjustment? would like some input from others on my situation.

[Mr.Atc]

I did another compression test and it has 160 pounds in 3 kicks. over 100 pounds on the first kick. the carb is spotless. the reeds are good but somebody used silicone as a substitute for the gasket between the cylinder and the reeds. maybe it wasnt sealing good enough? could the aftermarket pipe just be a pile of junk? maybe i should put my stock pipe back on

[SUPERBEAST]

is it bogging down on the low end?

[3wheelrider]

Lot more info needed to better help.-You say you jetted it after the pipe install-so what jets are in it? What carb?- '85 round slide? (toss it!)- or other? What size,porting,etc. Did this happen just after the pipe install & jetting? Or before & after? How do you know jetting is perfect?- By the color of the plug? -Thats no way to tell what each circuit is doing. Sure sounds like a jetting/tuning issue to me though....

[Mr.Atc]

the bike is completely stock no porting or anything only thing aftermarket is pipe and silencer. does have the round slide carb i believe stock size main jet is 142? it is 2 sizes up from stock jetting. if im just riding it normal and i pin it it just spits and sputters and acts like its completely loaded up. but it will clear up if i run it hard but soon as i drive slow for a minute it goes back to running like crap. if i get it going and run it fast and check the plug its golden brown. but if im in 1-4 going like half throttle it smokes really bad and doesnt want to run good. it never did run like this it ran pretty good even after i first put the pipe on but i did notice i lost some low end with the pipe but it never ran like this. i know its a 2 stroke and they load up but ive owned lots of them and this one if your not tapped out it doesnt run good. never had that problem until i changed the pipe and jumped up 2 sizes with the main jet. the pilot is the stock size. im thinking maybe that silicone on the reeds might have been leaking but if it was sucking air wouldnt it have been revving high? or maybe float needs to be adjusted

[Mr.Atc]

i also thought maybe transmission oil was getting in and getting burned somehow but ive been checking it and its not low at all. or maybe antifreeze was getting in. but the anti freeze is never low and i can never smell it being burned

[SUPERBEAST]

sounds like you need to mess with your jetting some more

[Mr.Atc]

wondering if i should find my stock jet and put that back in there. or if i should get rid of the pipe too.

[SUPERBEAST]

go up one size on your pilot jet, you said the stock one is still in there right?

[DohcBikes]

Go back to how it was when it ran good, just to see if it still does. Then do some thinkering.

Yep, Thinkering. I just came up with that, just now. You are all welcome.

[shortline10]

Aftermarket pipe doesn't = bigger jets . Go back to the stock jet and do a plug chop .

[Mr.Atc]

I ran it with the stock jet in it when I changed the pipe and it was too lean thats why I bumped it up a little.

[Jason125m]

wondering if i should find my stock jet and put that back in there. or if i should get rid of the pipe too.

It is definitely not the pipe. I have the exact pipe, with a matching bills silencer and it runs 100 percent. Sounds like you have some jetting to do. Those 85 carbs aare notorious for jetting issues...

[Fox250R]

Mine was crapping out on the low end right after I installed my Paul Turner high rev. Figured out it was the combo of my needle and plug. Just messed around with it till I got it right! Been running a BR8EG ever since and it runs great! Kind of a blur what we did with the needle lol sorry..

[Mr.Atc]

The guy who had it before me used silicone for a gasket on the reeds not me. I thought maybe that had something to do with it and yes gray plug so I jetted it up a little

[Mr.Atc]

I just cleaned it tonight and used a paper gasket but its too late to run it now and see it would wake the neighborhood up. I should have sprayed starting fluid around it when it wad running before I took it apart. That would have told me if it was sucking air. Believe me I would never use silicone on something like that. I have friday off of work so im going to tinker. Try stock jet and maybe a hotter plug.

[Dirtcrasher]

I'm sure you know the simple ways to check for an intake leak.

Does it have an airbox and with a lid??

Put the lid on, runs worse?

Take it off, runs better? More air matches more fuel.

Make ONE jetting change at a time until you have years with ears of tuning!

Get a simple notebook and record all changes/dates/sizes/temp/above sea level height etc. It will be very valuable in the future and help your ear with jetting.

[Mr.Atc]

Airbox and lid are on. Was thinking about taking airbox our and running a k and n right off the carb

[RIDE-RED 250r]

By the way you are describing the problem it sounds to me like you are rich on the low side.... Also, make darned sure your enrichment (choke) circuit is clean and clear and functions properly.

An air leak would make it lean and erratic, not rich. Jetting would seem all over the place and impossible to nail down. I don't think you have an air leak, your issue sounds too consistent.