jetting problem/quiery...

[Jakobi]

Its funny cause I actually thought of Dave today too. Hahah! Now I have faced my first issue. The digital vernier is definitely not accurate enough to take these measurements or not calibrated as well as it could be. One or the other. I can get some pretty consistant measurements with the calipers from one needle to the next but they don't fall in line with documented measurements. Particularly needle diameters.

I have one question to ask though. I need to accurately know where you feel the issues are. Is it between 0-1/4 throttle? 1/3 to 3/4?? 1/2 to WOT?? etc.

Believe it or not coming up the needle from the bottom a certain distance and comparing a NEDW and N3EW they are very very similar. From what I've plotted it would have to indicate that the NEDW is a bit rich as it starts the second taper a touch earlier, but by the time it ends its the same thickness as the N3EW at the same spot. This is about half way between half throttle and 3/4 throttle. From this point the NEDW supplies heaps more fuel than the N3EW but its also getting right towards the main jet.

I feel the lean area is this gap before the main supplies. Ie Both sides of half throttle. Below and above are good with the N3Ex needles.

 

[lonetree]

looking at at the two needles, i cant belive how much difference there is between n3xx and nexx, cause as you say they look such similar sizes..
from what i can work out with the n3eg im running, if i set up the bottom to be crisp, i seem to run lean somewhere just around 3/4 throttle, then once it gets too wot its running good again, screaming in fact, especially if i have a 178-180 main but then the bike gets hot, plugs go light if i run just under full throttle. plus the "missing" thing, sounds like its just not getting enough fuel, that happens about 3/4 to 7/8 throttle..

 

[Jakobi]

So you feel that the bike runs great from Idle - 3/4 throttle, and then just falls a bit flat/lean on top. It should be really easy to test this one but having someone turn down the end of the needle.

I personally feel that it may be more between 1/2 throttle and 3/4 throttle where its falling lean, then above 3/4 through to WOT feels rippin.

I think I might have a go at doing it with my N3EG which is too rich for my liking off idle, but will let me know if it does indeed clean up the slight lean area in the mid/top. Or I might ask around some local engineering shops and see if they can turn it down.

 

[lonetree]

not quite, its about 3/4 where the trouble is i think, its hard to explain and i keep running out of paddock to get real accurate plug chops...
i think the tip diameter is about right too, i think a new taper from about halfway along to the tip, keeping the original tip size... im guessing there is a hump in there somwhere that could be flattened out... need to do some accurate mesuring, and profile plotting first...

 

[Jakobi]

Yeah I've done some plotting today on some graph paper. I need to take a few more measurements to compare the needles at 3/4 to WOT and see how much variance there are at a few points. The two needles are pretty much the same for the first third. Slightly different after that. About the same from 1/2 to just past again, and then the big changes will be right on 3/4 which falls in line with your findings.

I'll be ready to either a) drop the needles at a shop, b) set up a way to modify one myself in a controlled method, or c) send a couple to Dave, within a few days.

 

[Jakobi]

I'm going to order another N3EW and N3CW in prep for when things get to the go point. I don't know how things are progressing with your man lonetree, but I have been drafting some stuff up and in discussion with dmcca. He is off on holidays for a while and will be purchasing a new lathe when he returns so could be a few weeks before he can work some magic.

Anyone else want anything ordered? Pick whatever diameter you prefer and after I do some test runs we can start getting them dialled down. Cheers.

 

[lonetree]

I'm going to order another N3EW and N3CW in prep for when things get to the go point. I don't know how things are progressing with your man lonetree, but I have been drafting some stuff up and in discussion with dmcca. He is off on holidays for a while and will be purchasing a new lathe when he returns so could be a few weeks before he can work some magic.

Anyone else want anything ordered? Pick whatever diameter you prefer and after I do some test runs we can start getting them dialled down. Cheers.

wow, you certainly dont mess around,... I haven't heard anything back yet, old retired guys can take a bit of time sometimes...

 

[Jakobi]

wow, you certainly dont mess around,... I haven't heard anything back yet, old retired guys can take a bit of time sometimes...

Straight into it. I'll probably send down a couple needles with a few different profile/setups that I think may work. The real moment of truth will be seeing if they do what I think they will. Hah!