KymcoForum.com
Scooters - 125 to 300 => Grandvista 250 => Topic started by: Kevin Hool on June 15, 2020, 09:39:34 PM
-
bought a used 2006 250 GV for my son to learn to ride on. Bike had been sitting in previous owners garage for years (like so many). Did the normal carb removal, cleaning, remove and blow open jets, make sure floats work etc... Had to replace the fuel pump as the old one had a stiff diaphram. Got the bike to start and run, but only with the carb intake open (no restriction). As soon as I place the air intake plenum back on, it dies immediately. Air box has brand new filter. I even went out and bought a conical air filter for that carb intake (45 mm), thinking less restrictive air intake, but same thing. With the conical air filter, it will run, but not rev, or deliver any power. I adjusted the idle mix screw both ways, but same thing happens. The main vacuum slide opens main jet needle and operate smoothly. Without the air cleaner, the engine runs very strong. I use rear brake to simulate load on engine. There is one thing I did modify, and that was the pilot jet. It was clogged so bad, no amount of carb cleaner, air pressure, even bent carb cleaning kit wires, trying to open it up. finally, ran a very fine drill bit (fit into the pilot jet opening freely, until it hit the jam) through the jet and got it open. Bike now starts, but appears too rich?
Normally with carb problems, getting enough air is rarely the problem. Stumped? Maybe nothing to do with carb operation?? Looked through the forum, but no luck. Once, my frustration level is too high, my logic for trouble shooting appers to disappear quickly. Welcome suggestions.
-
Just went through that on a People 150 was told not to enlarge the hole or it would cause problems. Mine was plugged up so bad that soaking in carb cleaner could not get them cleaned out . Some people had success using copper speaker wire so it would not enlarge the hole. I ended up purchasing another carburetor.
-
You could replace the pilot with the same jet size and that would either prove or eliminate it as the problem.
-
thanks for quick thoughts.
appreciate if you have a quick link to any parts providers or an OEM or equivalent idle jet for this bike. I'm totally new to the Kymco family.
I'd love if it was a simple as an idle jet.....
-
when I cleaned my dirty pilot jet last year I found it had 2 sized openings, bigger on one side and smaller on the other....if you stick something in there as large as the main opening and then drill through the rest of the pilot you will enlarge it way too much...if this makes sense.
So I believe you have enlarged the opening too much. Can you buy a new pilot jet?
-
As long as the jet is designed for your carb type I would trust the size number of generic jets. Or you can go genuine for peace of mind. The size number should be stamped on the top or the side of the jet.
-
Did you remove the emulsion tube when cleaning? If so you probably lost the "needle jet" - a small brass sleeve that goes thru the opening in the carb body - that the needle slides thru.
Easy to see if it in place when the carb is removed - look at where the needle enters the carb toward the main jet. You should see the brass slightly protruding from the carb body. It will run very rich if it is not in place.
See my posts in the Bet and Win 250 area about it for more detail.
-
I'll try and hunt down any jets that will fit that carb,...was hoping someone already had a good parts supplier link ready at hand for Kymco stuff.
As far as the needle....it goes directly into the main jet and when fully closed throttle, the needle blocks the jet passing fuel..
Not sure what brass sleeve other than the main jet you might be referring to. Main jet is in place, and needle operating smoothly when throttle opens and vacuum sucks needle up out of main jet to allow more fuel into carb.
will try to acquire a new pilot jet and see if it improves anything.
-
I have partsoutlaw.com bookmarked for my People S200. It has parts schematics and shows all the carb parts (including pilot jet) for my scoot. I don't see the Grand Vista listed...but I do see a bunch of other 250cc models.
Maybe you look at the schematics and see which of the other 250s share your carb?
-
just a quick follow up....after trying in vane to find a parts supplier (including partsoutlaw...who had the cross reference part, but could not get it from Taiwan)...I simply went to ebay and tried the purchase of a carb jet kit (10 different size jets for Keilhn? carbs). It worked perfectly. I used a 4.5 mm pilot jet size and its now running as it should.
I did have to go through the process of resetting the A/F ratio screw and the throttle set screw, but fairly easy to get it close enough for it to run as is should.
So there you go, ONE in a ROW.....lucky strike on Ebay.
-
Hey, way to go!
And much thanks for posting the 'fix' to your running issue!!
We don't get the 'fix' often enough....just the gripe😊
"One in a row", we'll take it!
Thanks again,,,
Stig
-
Glad they worked. I somehow got the lucky pack as well.