Log in

View Full Version : big red sputtering at low RPM



pudge
12-04-2010, 11:30 AM
my buddy has an 86 big red 250es. he got it a few weeks ago. it sputters and hesitates when you just start to give it gas, like at start up of after making a turn in the woods. then it suddenly runs perfects and jerks up to speed running smooth. it seems to happen mostly in 1st and 2nd gear because on the others the rpm can be kept higher. it idles fine. he says the gas is new, but im not sure about that

i figured maybe the air filter was clogged because he bought a uni and over oiled it. i removed that and it still happened

then i figured there was some rust in the petcock or at that screen, it was kinda gunky so i cleaned it, didnt fix it.

so the next option was to clean out the carb, which i did with cleaner and my air compressor, it didnt help. i never rebuilt an 86 carb before, one hole where a jet would go on the 85 was plugged with a rubber thing, i dont know

any ideas?

new carb kit? new gas? air-fuel problems? i wanna get this thing out of my garage so i can tune up my 86 sx and do the rear swingarm bearings on my 85 sx

Thorpe
12-04-2010, 03:23 PM
Carb kit...

pudge
12-04-2010, 05:18 PM
thanks , thats what i figured. i have had good luck with a good cleaning but a kit is only $20, it needs new gaskets anyhow

kos kruiser
12-04-2010, 06:24 PM
Gaskets not the problem,I think you need to look at your jets .

pudge
12-04-2010, 06:30 PM
Gaskets not the problem,I think you need to look at your jets .

i know the gaskets arent causing the issue, i was saying that they need replacing, they are dried out. the carb kit is only a few bucks more that the gasket set

Thorpe
12-04-2010, 07:46 PM
Be sure to check the new jets out carefully... I had a new kit for my BR from Dennis Kirk, new jet was labeled correct #, but the hole was monsterous! Had to have been 30-40+... Never ran right till I ordered a new kit, again...

pudge
04-02-2011, 10:15 AM
turns out it was the ignition coil had it tested and it wasnt up to snuf. ordering a new one, we'll see how it goes