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GPX 250 loosing power

Posted: Sun Oct 17, 2010 2:22 pm
by jgord154
hay guys ive neva used dis b4 but im in need of sum info i just brought a 89 gpx 250 wen i go to start it, it takes a while to to kick over an wen its warmed up it wont idle properly.......i managed to get it goin an took it 4 a run down da run cum bak turned it off left it for an hour or so came bak out an went to start it it took along time to kick over even wiv da choke, wen i did manage to start it again it was making a snapping, cracking sorta noise an wont idle or anything ................so has an1 got got any ideas thanx so much

Re: GPX 250 loosing power

Posted: Sun Oct 17, 2010 2:28 pm
by robracer
Change the plugs first & see is that works for starting, as for idle ..... carbs probably need an overhaul ;)
Oh & welcome to KSRC

Re: GPX 250 loosing power

Posted: Sun Oct 17, 2010 2:40 pm
by Gosling1
jgord154 wrote:....hay guys ive neva used dis b4 but im in need of sum info ..... an wen ... da run cum bak .. even wiv da choke, wen .... an1 got got any ideas thanx so much....
Brother - good luck with your bike. Welcome aboard.

But for fucks sake - keep the text talk for the iPhone eh ? and learn to spell. This place is not your fully sick bro's phone !!!

thanks

8)

Re: GPX 250 loosing power

Posted: Sun Oct 17, 2010 2:41 pm
by jgord154
thanx i pulled da carbies off wen i 1st got an gave dem a complete clean an ripped out da spark plugs an dey were sparking great an gave dem a sand down

Re: GPX 250 loosing power

Posted: Sun Oct 17, 2010 2:43 pm
by jgord154
sorry im still use to typing like that i will do my best to spell normal thank you for the advice :D

Re: GPX 250 loosing power

Posted: Sun Oct 17, 2010 2:44 pm
by waynemorgan
Welcome aboard - good luck with the bike. There's lots of great advice available here from some knowledgeable people :D

Re: GPX 250 loosing power

Posted: Sun Oct 17, 2010 2:55 pm
by Gosling1
jgord154 wrote:sorry im still use to typing like that i will do my best to spell normal thank you for the advice :D
thanks mate - that is heaps better. I don't want to sound like a cranky old pedantic retard ( even though that is a really accurate description :lol: ) - but txt language on a forum just irritates me to the max...

OK - about your bike - what Robracer has suggested is a great start. New plugs are mandatory, and you should take the carbs off and give them a really good clean with some pressure-pack Carbie cleaner (from Supercheap) and blow-dry the insides with compressed air. I can almost guarantee that your idle circuits are blocked and gummed up with old fuel deposits. This stuff may need a few rinses to get rid of completely.

Take the fuel hose off the carbie - turn the tap on - and see what sort of fuel-flow you get out of the tap. You want it to be nice and solid, not just 'dribbling' out - this would normally mean a blocked internal filter (inside the tank). You may also need to ensure that the vacumn line from the fuel tap to the inlet manifold is not cracked or split, this can cause problems with fuel flow.

8)

Re: GPX 250 loosing power

Posted: Sun Oct 17, 2010 3:26 pm
by jgord154
i dont have a airfilter in the bike is that going to make any difference ??????

Re: GPX 250 loosing power

Posted: Sun Oct 17, 2010 4:09 pm
by Ratmick
jgord154 wrote:i dont have a airfilter in the bike is that going to make any difference ??????
It's going to make the possibility of having crap in your carbies a bit greater than average ;).

A clean should sort this out, although if you strip them down completely and don't put them back together properly they will make your life a world of pain...but I guess you have that already.

Mick 8)

Re: GPX 250 loosing power

Posted: Sun Oct 17, 2010 9:57 pm
by jgord154
will not having a airfilter make the bike run rough????? i cleaned the carbies and it starts but it wont run without the choke

Re: GPX 250 loosing power

Posted: Sun Oct 17, 2010 10:26 pm
by GPZ_Jim
running with no filter would lean it out eh? would make sense why it won't run w/out the choke.. definately try n source an air filter ASAP :)

Re: GPX 250 loosing power

Posted: Sun Oct 17, 2010 10:33 pm
by waynemorgan
Sounds more like the pilot circuit in the carb is blocked....

Re: GPX 250 loosing power

Posted: Mon Oct 18, 2010 6:40 pm
by Gosling1
jgord154 wrote:will not having a airfilter make the bike run rough????? i cleaned the carbies and it starts but it wont run without the choke
it makes a huge difference. The reason it won't run without the choke, is that it will be running way leaner than it should be without the filters - is the airbox hooked up ?

You really need to ensure that the pilot jets are cleaned out as well, as Wayne M has suggested. Any blockages here will cause rough running at idle.....

8)

Re: GPX 250 loosing power

Posted: Mon Oct 18, 2010 7:21 pm
by jgord154
yes the airbox is hooked up but i brought the bike in peices and it didnt have an airfilter, but i did buy airfilter foam today
thanx everyone for the advice i will let you all no after the weekend if cleaning the pilot jets and putting on the airfilter has help

Re: GPX 250 loosing power

Posted: Mon Oct 18, 2010 8:31 pm
by Gosling1
One other thing you should also check......take the tops of the carbs, and have a real good close look at the diaphragms that are on the top of each carbie slide. If you spot any small pinholes or rips - the diaphragms are stuffed and you need new ones. Just hold the rubber up so you can see if the sun shines through any tiny holes - if you don't see any, that is a good sign..... :kuda: