ninjette.org - View Single Post - Misfiring, bogging at specific RPM (7.5K-8.5K) !

vtrider · October 11th, 2019, 05:52 PM

Hm, my earlier post is still not up, so I'll paraphrase it here:

Took some measurements of the main jets and they appear to be Dynojet DJ type jets, inner bore was roughly 1.09mm so Keihin 112 / Dynojet 108. Looking at dynojet stage kits, my best guess is the PO bought a stage 3 kit which comes with a Dynojet 110 main. Stage 3 is intended for bikes with pod filters. This would help explain the rich bogging at WOT because the bike has a stock airbox (with snorkel removed).

Still not sure I quite understand the mechanics of the "flat spot" being so closely linked to RPM, uphill and downhill (which I imagine would make a big difference on vacuum pressure) but getting this sorted out and seeing where it leaves the bike seems like a good way to go.

I've got some Dynojet 96s and 98s in the mail as well as stock keihin pilot jets, and we'll see how that does.

Do you think the Dynojet needle will work well with the Dynojet 98 main?

October 11th, 2019, 05:52 PM	#24
vtrider ninjette.org member Name: Ethan Location: Vermont Join Date: Oct 2019 Motorcycle(s): '09 Ninja 250R, '04 KLR 650, '74 CB350F Posts: 17	Hm, my earlier post is still not up, so I'll paraphrase it here: Took some measurements of the main jets and they appear to be Dynojet DJ type jets, inner bore was roughly 1.09mm so Keihin 112 / Dynojet 108. Looking at dynojet stage kits, my best guess is the PO bought a stage 3 kit which comes with a Dynojet 110 main. Stage 3 is intended for bikes with pod filters. This would help explain the rich bogging at WOT because the bike has a stock airbox (with snorkel removed). Still not sure I quite understand the mechanics of the "flat spot" being so closely linked to RPM, uphill and downhill (which I imagine would make a big difference on vacuum pressure) but getting this sorted out and seeing where it leaves the bike seems like a good way to go. I've got some Dynojet 96s and 98s in the mail as well as stock keihin pilot jets, and we'll see how that does. Do you think the Dynojet needle will work well with the Dynojet 98 main? Last futzed with by vtrider; October 11th, 2019 at 06:52 PM.