needle jet

Can you remove the needle jet? Not the jet needle, but the jet itself? I have 1 carb i'm having trouble with and yould like to inspect the jet. Can i get to it by taking the main jet off or do i have to go through the top? I have VM24's

Post edited by: vach, at: 2007/07/15 18:40

Anyone? Is there a way to take out and clean the needle jet on my carb?

Yes it can be removed. I suspect you would be better off if I didn't tell you because when you reinstall it, there is a definite chance you will bugger it up. The needle jet is just press fit in the hole in venturi. You take out the main jet holder tube and find something round and just a shade smaller than the orifice on the top and tap it down towards the bowl where the jets are. I have made a tool to do this. The problem isn't removal it is putting it back in. Make SURE you have it started in the hole and then tap it back through into the venturi. If you get it a bit sideways, it will bend up the edges and you will ruin it. DO NOT stick anything into the hole itself as this can ruin the sizing on the needle jet and even a slight size increase because you stuck something in the hole can make a huge difference and make tuning impossible. Why do you think you need to remove the needle jet would probably be a better question? Last point, if you bugger up the needle jet, keep in mind that there are no replacement sources. I can get them for the Z1 but those won't work on your bike. The needle jet has a "badge" number that is something like 258 0-5 where the 258 is the TYPE or STYLE of the needle jet and the 0-5 is the size. There are at least 3 or 4 different styles/types used on the VM carbs.

Post edited by: wiredgeorge, at: 2007/07/18 15:39

Thanks, WG.. I took off what I believe to be the needle jet in the diagram. My #2 carb is fouling out plugs and I can't figure out why.. They are clean as far as I can tell but I have a few problems. The wet float test is good at 23mm. The bike runs good at idle and throughout the rpm band but as i said the #2 carb is fouling plugs. Also The #1 air mixture screw has no effect what so ever. I can take it all they way out or screw it all the way in with no change at all. The other air screws will kill the bike if i turn the either way. the bike is very hard to start.. 20-30 kicks with the choke on only unless the bike is hot or warm, it will start right up. They are all set at 11inches if vacuum. Is it possible that the choke jet or starter jet is clogged on the inside? All the holes seem to be clear but I think they may be clogged inside. It might be time to send them to you..

Post edited by: vach, at: 2007/07/18 16:52

The thing you have marked as the needle jet isn't. That is called an "emulsion tube" or "main jet holder tube". The needle jet is still in the carburetor... the little piece of brass or stainless up UNDER the emulsion tube and press fit into the venturi... If you look through the bore of the venturi, it is on the bottom in the dead middle. There are three air jets; a main jet air jet, a pilot jet air jet... these two sit on the venturi edge and either can clog. These air jets combine air with the slide cut out when the slide is closed to provide air to their respective circuits. The choke air jet sits back in the venturi about 1" on the choke plunger side and can clog but wouldn't foul plugs since the plunger is SHUT when the bike is being operated and no air gets through this circuit... only when plunger is up.

If your carbs have both pilot fuel mix screws and air screws, get another set with only one or the other; preferably just air screws as these are far easier to tune for the average person. The carbs you have very likely are a tuning nightmare. If you have a barb on the #2 carb for vacuum for the petcock, make sure gas isn't getting back into the carb via the vacuum line to the petock because the diaphragm is bad. This can be an issue as well.

If the needle jets are badly worn, the bike WILL run rich. The hole that the jet needle fits into (the needle jet) elongates from wear over time and once it starts wearing, gets greatly elongated. This is more likely to occur on the non-clipped type jet needles where they have the little plastic donuts and spring as these things put slight sideways pressure on the jet needle and it WILL wear the needle jet.

Sorry I didn't post i lost my internet connection for a day.
Post edited by: vach, at: 2007/07/19 13:29

Post edited by: vach, at: 2007/07/22 12:29

Well, After inspecting the needle jet it seemed to be ok. I did find however a small pinhole on my #2 float. it seems it was buoyant some of the time. That was causing the plug to foul.. Now i have to figure out why such hard starts. The bike runs great. i think the starter jet is gunked up somewhere on the inside. The holes in it seem to be ok though so I'm not sure. What is the best way to pull these out without destroying them?

I just broke my kickstarter!!!!! from kicking the crap out of the bike all the time..:blink: My electric start doesn't work because the fteeth on the lywheel are ground off. Does anyone have a kickstarter I can buy?

Post edited by: vach, at: 2007/07/22 12:36

what broke on the kick starter

The part that swings out.. Thers's a groove for a keeper on the bottom of it. The keeper is gone.. I have the ball bearing though. I just put a new keeper on it but the kick starter just flaps around.. It won't stay in place. There is no room to get a bigger one on there. It's as loose as a goose.