Pilot Jet Style.

[1948man]

http://www.z1enterprises.com/ItemDetails.aspx?itemDescription=Pilot+Jet+VM22%2f210+%23+32.5&item=TU42-3290-1

I want to go from a #40 pilot jet to a #42 on my 1100G due to a slightly lean condition. The #42's I have are of a sightly different style of the ones linked. The difference is they don't have the series of holes on the sides of the shaft. I'm not sure if you can find #42's with the holes on the sides. Will it make any difference? I have checked for other possible causes of a lean condition. Intake boot o-rings are okay, mixture screws are 4 turns out, etc. I had the bike on a dyno and it was good but a little lean in all circuits. It's perfect when warm but hard to start on even mildly cool mornings. I got the 42's from Z1 a couple of yrs ago.

[chef1366]

Put them in
They will work.

[almarconi]

Don't think larger pilot jets are going to cure your hard starting when cold. About the only thing the larger pilots will do is allow you to close your mixture screws a couple of turns. So if you are 4 with 40 you will probably be about 2 with the 42's. I would make sure your choke circuit is clean and working properly. Make sure valves are adjusted properly and that your compression is good on all cylinders. These bikes should fire with choke/no throttle almost instantly. If it is lean on all circuits you may also consider the possibility that the petcock is not delivering an adequate amount of fuel. Did you also measure the amount of fuel in the carburetor bowls? The fuel height will also effect whether you are running rich or lean.

[1948man]

Thanks for the replies. New petcock, valves adjusted etc, but the choke does act a little funny. It's hard to find the sweet spot. It either wants to idle real high or die when cold. I will look into that. Is there a point beyond which backing out the mixture screws really has no effect. I was thinking beyond 3 1/2 turns might not really be richening any. i may be beyond 4 turns, actually.

[almarconi]

It's pretty normal for the engine to idle high 3-4 rpm on full choke. As the bike warms up, begin to close the choke. When fully closed the bike should idle smoothly. Check the height of fuel in the float bowls since this will effect whether you are rich or lean. You will need to attach a clear piece of hose to the drain fitting on the bowl and measure the height of the fuel. The procedure is outlined in the service manual. This is often overlooked since most people just set the float height and forget it. Floats can leak so even thought the height is set per the spec. the amount of gas in each bowl is not the same.

[1948man]

Thanks, I will check the float heights.

[chef1366]

While you are in there make sure the holes are clear on the brass pick up for the choke that goes in the float bowl. Take carb cleaner with the straw and spray it in the hole where the choke plunger sits and it should come out the small holes in the pickup.

[almarconi]

Did you have a chance to check the engines compression?

When you get the carbs assembled, before you put them back on the bike, rest them in a vice and check the fuel level
in the bowls. You can make an adapter for the bowl screw by taking an old screw and drilling a hole through it, JB weld a
piece of tubing in the hole. Hook up a piece of clear tubing to the bowl screw, fill carbs with gas and check the level of gas in the tube. You want the level to be around 4-5mm below the gasket surface, check the service manual for the exact spec.

[Steve]

I saw some assurances about valve adjustment and intake boot o-rings, but did not see any assurance that the carbs are CLEAN.

When was the last time the carbs were CLEANED and re-o-ringed? If you don't know, it's probably time to do it.

Your symptoms sound like clogged passages that will be cleaned by a proper dipping.

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