Idling issue 40 pilot jet

[jjkozul123]

I got the 40 pilot jet kit with 110’s.

When I look at my stock carb, I see my 105’s, and they’re a long tube with a tube which houses the diaphragm needles, however, the 110’s I ordered don’t screw into the housing where the 105 is. Is there a special way to install the 110 or what am I missing out on? I ordered a keihin kit off of eBay, one shim for each needles has been installed. Is it possible they sent me the wrong 110’s or does the piece under the stock 105 need to be unscrewed or something. Thanks

[ducatiman]

nd1.jpg

Main jet (circled in red) simply screws into the long emulsion tube. Mains can be removed in place. Perhaps using an 8mm wrench on the tube (to keep the tube from spinning) will help?

[jjkozul123]

https://ibb.co/YtTwBZr

So does that mean that the circled green part is where the jet screws into? Do I have to hold it with one hand and unscrew the old 105 jet with the other? Would the 105 in any way improve my starting issue. The 40 has improved it but not necessarily cured it altogether.

[DannoXYZ]

Carbs have multiple circuits which supply petrol at different operating zones. Main and pilot jets really don't have much to do with starting. That's mostly choke-circuit. Rather than replacing jets, which represents only small portion of petrol's flow path, you'll want to clean entire path from beginning to end. Starting at tank & petcock.

Here's good photos of all circuits that need thorough scrubbing with brushes and PEA-base fuel system cleaner (also shows where choke-jet is located). http://n4mwd.blogspot.com/2013/10/se...-passages.html

Recent case had choke-jet so clogged, it needed to be drilled out! Then bike would start much easier. Try poking it out with soft copper wire first.

[ducatiman]

Originally Posted by jjkozul123

https://ibb.co/YtTwBZr
Would the 105 in any way improve my starting issue. The 40 has improved it but not necessarily cured it altogether.

clearly a pilot jet/screw position/pilot jet truly clean/able to flow type issue. Resorting to oversized 40's is masking an underlying problem (partially clogged pilot jet/port). Consider adequate valve clearances are critical to starting as well.

[jkv45]

What modifications have you done to the engine?

They almost never need larger (40) Pilot jets to run right, even with pods. You may end up with the idle mixture screws farther out with the stock 38s, but you should be able to get the proper setting.

110s are plenty rich as well. We ran 108s with pods and a leaky stock exhaust, and it was plenty rich. Probably could have just stayed with the 105s.

Unless you need to make major mixture corrections due to extensive engine mods, going richer isn't going to be any better - and probably worse.