Carb problems on 250R

[Honda47]

I have a 1986 Honda 250R I just got, I'm having some apparent fuel/carb problems. I've been riding it about a week and the other day it all of a sudden started bogging down and I couldn't keep it to stay running. When I would shut the gas off it would run good and then when I would leave it on it would bog out again, so I checked the floats, seemed ok. Then when I put it back together I unhooked the airbox and just ran it with nothing hooked to the car, it ran fine with the gas turned on. So I hooked back up the air box and it started running like crap again.

I have run out of Ideas if someone could help I would appreciate it greatly.

Mike

[12blaster34]

the jetting is probably set up to have the airbox lid off if it works fine when it is off.

[Honda47]

The only time it works, is when everything is completely unhooked from the carb. Even leaving the airbox hooked up and the air cleaner off it runs bad. It only runs good when nothing is hooked to the carb. The jetting hasn't been changed it just all a sudden started running bad. The gas I put in is not the same as i had been running, I ran a mix 50/50 of 91 oct pump and 100 ll avgas..........Please help

[TRX370R]

First thing I think I would try running the same type of gas that you were using before the symptom occured. Also I would check the main jet. I have had the main jet come loose and fall out, when I would get over 3/4 throttle it would bog out. Good luck

[Honda47]

Would a change in gas change the required air intake?

[TRX370R]

It doesn't exactly require a change in the intake but a change in jetting. I usually run VP C-12 straight, but on one ride I tried Trick 110 straight, the bike idled higher, started pinging, and would even backfire alittle bit. Checked the plug and it was running lean, I inspect for an air leak but was unable to find one. So next ride out I switched back to the C-12 and it was back to normal. I'm not saying that the C-12 is better then the Trick but it did have an effect on my air/fuel mixture.

[Honda47]

I was running true blue in it so maybe I should try going back to that.....Thanks

[Honda47]

I tried putting the race fuel back in and it does the same thing, I even tried putting the stock carb back on same thing still. I have it put back together and I can keep at an idle but if I give it gas it bogs out. However if I just fill the bowl and unhook the tank or shut it off it runs pretty good. Sounds like float is stuck but it's not it isn't leaking out overflow tube either. It does spray out back of carb though and leaks between the air box and carb.
Is this a reed valve problem? Some one told me it sounded like it but I'm new to 2 strokes so any advice would be great...........

[Quadguy08]

I used to have somewhat of that problem. When I ran my 250r one day it worked okay then the next day it bogged at full throttle. I first thought the problem was with the air filter but when I cleaned it, the problem was still there. I then opened the carb and found the main jet floating in there. After I screwed it back it worked fine again.

[Honda47]

Jets are all fine, both carbs do the same thing. Does anyone know if this problem could be because of the reed valves.......Also it stuck wide open today and I thought the throttle was stuck but it wasn't I had gas in the bowl but the tank was off the four wheeler. So i pulled the spark plug wire and it still ran for about 5 more seconds....How the heck is that possible. But anyway I was told if gas is blowing out the back of the carb bad reed valves is my problem but before I spent the money I wanted to hear some more opinions on what could cause my original problem.....

[quad250r_33]

Did you check the carb boot for holes mine did that for a while until i found a small hole on the side towards the carb.