Hoping for quick reply! - fuel problem *NOW FIXED!*

[Gosling1]

Have you found the problem yet ? Would be interested to see how this turns out, hopefully not too co$tly.

cheers
Dave

[HemiDuty]

Well, here is the latest. Me n Bob next door (thanks for the help mate) have pulled the plugs, they are all old looking but functioning ok, I will get new ones but nothing was available today so they will suffice for now. The fuel tap appears to be working fine, I pulled one of the fuel bowls off and unclogged all the shit in it, it now has fuel come out when I remove the screw at the bottom, so will do this to all the carbs soon. But that also isn't the problem, I just test rode it and the problem seems worse.

Basically it just doesn't want to work on full throttle. The more throttle is applied, the worse it gets. So it actually goes a bit better on light throttle than anything, but it is way to slow. It is like it doesn't like load. The problem is worse up in the rev range too. I can't really tell if it is missing or what, it just won't go properly.

So I think it is carb related, does this sound like the most likely possibility? Unfortunately I am going to have to pull the damn things off, doesn't look real easy but I cannot see anything else working. I will try to get hold of some diagrams and such to get em off and strip/clean them. I am thinking maybe a main jet or 2 is blocked or something. I dunno.....

So anyway I will be unable to go on the ride tomorrow.

Thanks for the input everyone, any further help would be great.

[mike-s]

I have a few suggestions

Firstly i think it might be an electrical problem. To check if it is, get a multimeter hooked up to the battery & see what kind of voltage you are getting on the batteries at full revs, the alternator should get it to about 12.8-13.5v at around 4000rpm and not go much higher or lower from that point up through the rev range. If the voltage cuts abruptly to below 12v you might have a problem with either the battery, or something in the charging circuit. As a side note, the alternator is at its most efficient from about 3500-8000 for a lot of bikes i.e. middle of the rev range.

If you think it is fueling, one thing you could try is the load&chop, basically put new plugs in or clean these ones up, get the bike up under full load for a minute or so, and then cut the throttle with the kill switch & see what the plugs look like, they should be a light - medium brown colour.

But seriously, just swalloW the $15 bucks and pop some new plugs in.

[HemiDuty]

Thanks Mr Dash S, will check the voltage deallie after the ride tomorrow (if I make it). I am definitley getting new plugs, I just couldn't get hold of any today (Sunday) so had to re-use the old ones.

[MickLC]

Does it do it when the bike is stationary or only when it is on the road?

[Glen]

Hemi

I've seen a Yamaha YZF1000 do something similar to this a while back. It turned out to be a kinked fuel hose which let enough fuel through at low revs but once it got up in the rev range the restricted hose just wouldn't let enough fuel through. Took ages to find. It sounds like you've had it apart a bit so the lines probably not kinked but it sounds like it's starving for fuel somehow.

Good luck with it

Glen

[HemiDuty]

Mick: Only on the road, under load. Seems to rev fine in neutral.

Glen: I agree it seems like fuel starve to me too, I cannot see any kinked lines when I take the tank off so that is why it leads me to believe it is somewhere in the carbs themselves.

[MickLC]

Mick: Only on the road, under load. Seems to rev fine in neutral.

I had something similar to that happen on my old 9, turned out the balance tube for the ram air had come loose and a cable tie fixed it up sweet. Not sure of the arrangement on the 7, but the 9 has two little tubes under the headlight that join together then head back to the carbs. Might be something simple like that.


EDIT...bugger, just checked the original post and saw it was the GPX giving the problems...oh well, worth a try

[Gosling1]

Hemi - quick'n'dirty alternator test - start the bike, turn on the lights, give it a rev - if the lights brighten, then the alternator is charging the battery, and the battery condition can be considered OK. If you want to check the charging voltage, put the multimeter connections directly onto the battery terminals. As mike-s has indicated, you are looking for a voltage reading of around 13v. Under 12v, it could be regulator / alternator, anything in excess of 14.5 volts will also stuff your battery ( once again, regulator / alternator problems.)

Is there an in-line fuel filter fitted to your bike ? Somtimes these cause problems with kinked lines, and subsequent fuel starvation problems.

Gotta get the carbies off and check all your needle/seats.......

cheers
Dave

[HemiDuty]

OK get this:- It was the bloody plugs after all! I checked the spark on the old ones (coz I had to wait till I could get down to Midtown to get new plugs), and they looked fine. But anyway, I got the new plugs and put them in, took it for a quick trip around the block and it is all good!!

So thanks for the help everyone, really appreciated.

The GPX is back

[Smitty]

OK get this:- It was the bloody plugs after all! I checked the spark on the old ones (coz I had to wait till I could get down to Midtown to get new plugs), and they looked fine. But anyway, I got the new plugs and put them in, took it for a quick trip around the block and it is all good!!

So thanks for the help everyone, really appreciated.

The GPX is back

mate

what fuel you running in the ol' girl???
just curious

[Gosling1]

Good stuff Hemi, I bet you are glad thats over

Were you using the resistor plugs - NGK ?? I have always had problems with them on my Zed, once they foul, its goodnight sweetheart.

B8ES rule, B8RES suck

Yoda - would you be thinking Craptimax ???

cheers

[Smitty]

....
Yoda - would you be thinking Craptimax ???

cheers

yeah mate
...or Indonesian ULP from the funny name servo

[HemiDuty]

The bike came with DR8ES-L plugs in it, and I bought D9EA NGKs for it. I run the bike on whatever standard unleaded is around at the time, it isn't (AFAIK?) a high-comp engine so didn't see the point of putting premium in it. Should I?

[Glen]

Good result Hemi, at least you got out of it without too many $$$$ spent.