GPX 250 loosing power

[JonW]

Do you know how long it has not had an air filter for?
I would also be changing the oil and filter once you get the air filter in. As an explanation, the air filter will create a slight difference beween the air pressure outside the bike and the air going into the carbs. This pressure difference will assist the carbs in getting fuel into the engine. Without the air filter the air/fuel ratio approx 14:1 is going to be running with too much air, therefore the mixture wont burn properly.

Thats why carbs/EFI need rejetting/remapping when the air intake or exhausts are changed as this changes the air fuel ratio.

The above is my basic understanding of the process.

[seiko1]

wotzdafukinprobgossybrowifdafkintxttype?

[jgord154]

thank you everyone i took the carbies off yesterday and clean them as good as i could and went out and brought a airfilter......shes running like a champ, i took it for a ride last night and i cant believe the how much power it has for a 250

[waynemorgan]

Glad to hear it - sounds like you're going to go and have some fun

[GPZ_Jim]

excellent to hear yeh the twofiddys have plenty of poke, but tend to run out of steam once ya start going over a hundred clicks

stay safe!

[sempsei]

Sounds a lot like the problem we had with my 1991 when we were fixing her up. In the end it needed a new needle and seat in the carbi. When cold it would start and then the carbi was basically flooding the cylinder head with fuel. Wait long enough and you could fire it up again and then she would loose power and die, then not restart. We got both carbs re-seated and syched and away she goes.