Topic: Needle clip position?

[MOD27]

My needle clip is on the second notch from the bottom is this a good position? what does the needle clip positioning do? I have an idea of makes it richer or leaner. If im running a stock air box and a 4 into 1 with no baffle what is a good needle clip position?

thanks,
mike

[BobbyR]

The best thing to do is read your plugs. There are several charts you can find online that will show you what plugs look like. Some like to do a plug chop, I just look at them after a few weeks of my regular riding. Do a search on plug chop if you want a detailed account of how it is done. Where in NY are you?

[MOD27]

Good old binghamton,ny...I pulled my plugs the other day seem to be carbon fouled.

[Tintop]

Raising or lowering the needle changes the position of were the taper starts to interacts with the needle jet.  Lowering leans, raising richens.  It is a way of fine tuning the mixture across all the carbs.  It is generally used after the basic mixture has been set using the other jets to get as close as possible.

Without knowing which bike and what carbs, kind of hard to know which is the right position.

[MOD27]

Oh yeah I forgot to metion that part.... it is a 1976 cb750k 110 on the mains for the 4 into 1 vance and hines no baffle,stock air box,the clip position is 2nd from the bottom.  That helps me out alot because i thought it was the other way around thanks for clearing that up! Im thinking it needs to go to the middle.

thanks,
mike

[Tintop]

The stock main jet size for the 76 was 105, so you are one over (110), and that is appropriate for adding an after market exhaust to a stock engine.  The 'no baffle' will lower back pressure, and cause leaness, it can also cause low speed drivability issues (flat spots).  A plug chop (use new plugs) will give you a good idea if you are a little lean, or a lot.  A little can be fixed with the needle, more will need a main jet increase.  Then fine tune with  the needle.