Some kind of fuel problem, HELP!

[joshy28]

Ive got a GN (yes i know...awesome )

I have a sluttering /slash/ backfire/bitta black smoke from exhaust/at times, strong smell of burnt pertol...Problem

It has got prgressively worse sinse i bought it 3 months ago. I mean to take it in for a service but have not found the time or money hwever, will take it soonish.

I use the bike every day, to and from work, but am getting very annoyed at the spluttering it does. Every time i take off at the lights, it will splutter untill i rev the F!@# out of it, then is seemy okay after 400oish rpm. However, after i have travelled on the motorway for 10mins, i seems to run okay without spluttering... could it be a carburetor thing? should i take it apart and clean it?

[CookMySock]

Choke is stuck partly on? Air filter is blocked? Try running higher octane fuel in it.

Steve

[joshy28]

Choke is stuck partly on? Air filter is blocked? Try running higher octane fuel in it.

Steve

choke is fine, im sure the air filter is fine, but ill check. i only use 95 or greater, mostly 98...

[mrchips]

Water in ya petrol tank maybe ?, doesn't take much spice things up a bit.

Try adding some Wynn's Spitfire Petrol Treatment to the petorl tank (only about 1/4 cup).

If there's any h2o in there it will help the poor thing digest it.

[joshy28]

Water in ya petrol tank maybe ?, doesn't take much spice things up a bit.

Try adding some Wynn's Spitfire Petrol Treatment to the petorl tank (only about 1/4 cup).

If there's any h2o in there it will help the poor thing digest it.

okay ill try that, see wot happens...it could be water as i dont have a garage to store the bike, however i do have a bike cover, but sometimes i do forget to put it on, on those rainy days...

its embarrasing wen 50cc scooters trash me at the lights, cos it almost looks like im stalling lol..anyway...

[Racin Jason]

whens the last time the spark plug was changed? could have high resistance in the plug cap, causing a missing under load at lower revs.
You can check if you've got a multimeter. shouldnt be much more that 8 K ohms

[joshy28]

whens the last time the spark plug was changed? could have high resistance in the plug cap, causing a missing under load at lower revs.
You can check if you've got a multimeter. shouldnt be much more that 8 K ohms

i bought at 6000km and since have done 3000km, so have never changed the sparks, how often do i need to?

Also, added the spitfire petrol treatment and is about 5% better.....

[jonbuoy]

Is it a lot worse after its been sitting at idle for a time? Could be floats or float valve problem. It shouldnt be too much hassel to drop the float bowl off the carb and have a looksie.

[joshy28]

Is it a lot worse after its been sitting at idle for a time? Could be floats or float valve problem. It shouldnt be too much hassel to drop the float bowl off the carb and have a looksie.

I dont know, havnt tried but will check the float. travelling 80+ on the motorway is fine. And if i travel on it for at least 10mins, it seems to get better.
1st and 2nd is when most of the splattering happens especially in the mornings

[joshy28]

i tookthe float bowl off, and ran the engine out... there was brown and black sediment there about 1 miligram worth. Ive cleaned it thoroughly and put it back. Only a slight change, but still spluttering around 3000-3500rpm...

havnt changed the sparkplug yet, but will do 2moro............

anyones have any ideas?

[joshy28]

changed the spark plug, and there is a difference. However, cold or left sitting for more than a hour, it still feels though there is a splatter in 1st but after 10mins around town its okay. I only changed the spark plug to the normal standard D8EA.... any suggestions on spark plugs for the GN250

[rok-the-boat]

Take the carb off and clean it. Check fuel flows properly, fit an inline filter - $2 from Cycletreads.