I need jetting help....

[Jakobi]

Too small. A couple sizes past the perfect spot could cause an issue. If you're a couple sizes rich it won't make much difference at all. You'd have to be pretty unlucky to lean size a warmed up engine by running a main thats only a couple sizes too lean on a relatively low load run, such as a quick spin down the street in 3rd gear. It should tell you immediately if the bike is running stronger. You'll also probably get some run on when you roll the throttle back, or some pinging, or general flat tinny sounding power delivery. If it feels wrong then stop.

Looking at the KTM blokes (different engines I know), they are all running between 160-165 mains in their 250 and 300s.

[hannesd]

Looking at the KTM blokes (different engines I know), they are all running between 160-165 mains in their 250 and 300s.[/QUOTE]

are they running 36mm carbs?

[Jakobi]

Originally Posted by hannesd

are they running 36mm carbs?

Indeed they are. Comparing ASII 36mm carbs to ASII 36mm carb as in Nathans bike. To be honest I actually believe he is running a carb from a KTM while his mate evaluates his 36/39 oval bore in the pumpkin.

[n_green]

Originally Posted by Jakobi

Indeed they are. Comparing ASII 36mm carbs to ASII 36mm carb as in Nathans bike. To be honest I actually believe he is running a carb from a KTM while his mate evaluates his 36/39 oval bore in the pumpkin.

Sure am. Identical carbs. Just the pumpkin had a notched #7 slide while mine had a notched #6.5 slide. All I did was transfer slides and jets across.

[n_green]

OK I'm happier ish now.

Went for a ride today - 38p, JD Blue #3, 168 main. 20 deg C, 300m alt. Was lightly sprinkling with rain most of the day.
85k's of 70/30 single trail/fire trail used 9.1l of fuel. Come back to the ute with 100mls of fuel

That gives me the same economy as when I used this exact setting prior to the head mod in similar temps but at 1100m altitude and low humidity. On that occasion I also dropped the needle to clip #2 and whilst it didn't make a huge difference in economy, in fact it didn't; it made the mid/top nicer.

I may attempt to drop down one more size on the main just to see what happens but I'll have the 168 ready to put straight back in. Also may drop the needle again as I now have an annoying rich burble between 1/8 and 1/4 throttle, which is right where the throttle sits on transport sections And incidentally is also what all the pumpkin riders get using JD needles in a 36mm carb.....

Power using this setting today was great, way stronger and smoother then using these settings prior to the head, although now it has a distinct transition onto the pipe so maybe I'm getting close with a main.

[Jakobi]

In my experiences the 18 tp 1/4 throttle region is pretty much the needle diameter. Unfortunately with JD that means jumping over to the red needle. Moving it to clip two will have a little effect at this point too - more so at 1/4 throttle than 1/8th though. Sounds like your getting close Nath.

[n_green]

Originally Posted by Jakobi

In my experiences the 18 tp 1/4 throttle region is pretty much the needle diameter. Unfortunately with JD that means jumping over to the red needle. Moving it to clip two will have a little effect at this point too - more so at 1/4 throttle than 1/8th though. Sounds like your getting close Nath.

I don't have the red needle. Actually the blue one is a borrowed/swapped needle anyway. My aim was to jet as close to perfect with the blue needle (based on Simmos baseline) and then start again using the Suzuki needles I do own anyway. One more quick run to confirm the main I'm using and clip position is correct which I'm pretty sure they are and the. I'll start using the zook needles.

As for the burble, it's only annoying on transport sections and is hardly noticeable when actually riding the trails.

So I'm armed with a NEDJ/W and NECJ/W. Any opinions on which one to start with?

[Jakobi]

Have you got any N3xx needles? If you haven't tried one you should

With the zook needles you'll be able to drop around 2 sizes on the main due to the rich 3rd taper. I'd start with the richer needle diameter so NEDW#3. You'll want to go up several sizes on the pilot to maintain the same idle and off idle response. I'm thinking a 42. Move from NEDW#3 to NECW#3, then to NEDW#2 and evaluate which feels better. Even try the NECW#2 if you think there's room for improvement, but if may be a bit lean for your taste I'm thinking.

The other option is just stick with the JD blue and the light burble. They will all burble a bit on light throttle during transport. You either has have to keep the throttle open further or closed and no more noises. Haha! I know you like to tinker though and experience the differences in making changes. I enjoy reading the feedback too.

[n_green]

Any thoughts on just dropping a JD red clip 3 in my carb without touching the jets? Going for a ride tomorrow and considering doing it to see what happens. Mate I borrowed the blue needle off will be there and is bringing the red. Tomorrow is purely for riding so I only want to play with the jetting once if at all during the ride.

I think the JD is a leaner diameter needle? So if I slot that in with current jetting will that have me too lean? I'll have the blue ready to go straight back in if there's any sign of being lean. Just wanted opinions before I do it and ride it.

[Jakobi]

Give it a go and see what you think. It should be alright. If its going to be lean anywhere it'll be off idle which you might be able to compensate for by turning the AS in to 1 turn out. You're doing alright gettin out for a mid weeker! Lucky bugger!