VLX Dual Carb Jetting with pod filters

Posted on by Admin BP

The Skinny on needles:

Ok, dropped my needles one clip to the 3rd position from the top. This seemed to help the off idle stumble a great deal. Throttle response in the 1/8 to 1/4 idle range seemed to be much better. Seemed to run better in downshifting from 3rd gear. I will ride it for a while and report back.

I could not drop the needle any more, I tried the next clip down, but couldn’t get the plastic needle holder it to seat in the slide. It looks like it could be done if you got a shorter spring and nipped/trimmed the plastic nub some, but didn’t want to try that, just noting it here.

So… while I had the needles out, I took some measurements and pics.

click the pics for larger versions. They are not the best quality, but you can get an idea of what these DJ1145 kit needles look like.

Here’s a link to the muniki needles that I was thinking might work, but not sure about the interchangeability of these needles in the kehign carbs and I’m not sure whiech kehin needles would be used that are most similar to the DJs.
Jets r us needles.

Well I just found out that I drilled/jetted my carbs to 159 main jets! That’s HUGE as far as sizing goes. Turns out aht Kehin jets are metric sizing (135s are 1.35 mm, 140s are 1.40 mm and so on). So the 1/16″ drill bit is basically 1.5875 mm or the equivilent of 159s. Ordered some more jets from Jets R us just now and will rejet again soon.

 

Also, don’t know if Jet’s R us sells the correct kehign needles for these carbs. the needles I was looking at (which seemed very similar to the DJ needles), were for Muniki carbs. I will take some good needle measurements with some calipers when I rejet (again…)

 

Bike is jetted! Runs GREAT in all throttle settings except WOT at the very top of the revs(~95mph). It chokes out just a bit at that speed/RPM, but I wont be doing that anymore anyway. Bike pulls MUCH more all the way through the revs and is MUCH faster 3rd gear goes up to 80 now, 2nd gear – 60. I can now remove air filters, carbs and rejet and have all reinstalled in under 30 minutes. This is primarly thanks to the test gas tank (that doesnt have to be removed) and having no airbox/hoses ect…

Current setup:

  • DJ 108 mains drilled out with a 1/16 inch drill bit. I figured I’d never need these again anyway. I was going to try some 140s, but nowhere in town carried them. Previously was 135s OEM replacements from Jets R Us.
  • pilot jets 42 OEM
  • needles set 2 clips from the top
  • idle air screws 2.5 turns out
  • using pod filters (seen below) WITH stock carb boots – Filters attached to end of the boots as opposed to straight on the carbs. The right carb did require a metal spacer that I got from the local auto parts store and hacked the ends off. May try longer spacers in the future to see if that changes anything.
  • many thanks to 3rd Degree and obnoxious on the shadowriders site. (http://www.shadowriders.net/forums/showthread.php?t=20644&page=9)

To Dos:

  • try longer intake runners to get pulse effect
  • run breather hoses and filters
  • sync carbs
  • do a plug pull

Previous WOT run:
6/23/2011 (idle air screw = 3.5 | pilots = 40[stock] | needles=2nd from top | mains=135):
Ran bike with air filters taped up 1/4 of the way. Bike ran great on the needle. lost power on top end. Would not get ukp over 95. Noticeable amount of popping on decel in high gear. Seemed to use a lot of gas.

 

 

OK, so I’m sick of the big ugly airbox. I’m trying pod filters on the bike now. Basically little pancake filters are added directly to the carb throats. This requires rejetting because there is more air flow. There is also another mod similar to this that others have had success with, called the Stax mod. Basically instead of pod filters, you put a couple of velocity stacks (that have filter material inside), and OEM125 main jets. Click here, download the PDF and check the thread for some very interesting reading. If you wanna go this route, you can email Hiro at West Eagle to order the Kajima Funnels for your bike.  He has the model information.  Hiro is a really cool guy and very helpful. His email is Hiro@west-eagle.com

Other Related threads/pages of interest:

shadowriders (many thx to 3rd Degree)

tank bottle (good idea for a temp/test tank)

West Eagle – get velocity stacks (if you wanna go that way instead of pod filters)

Three basic components needed for this mod to work correctly: Jet kit DJ1145, Scooter Assasins Pancake Filters PN#400208986706 , Main Jets (OEM135)

You can get the DJ kit from lots of places, other similar filters and jets may work as well. JetsRUs has a simple easy to use site and in addition to carrying OEM main jets they also sell allen bolts for the carbs, and a surprising array of needles. The theroy behind the allen bolts is that you can use them along with a ball head allen wrench to remove the slide cover (and maybe even the float bowls) without removing the carbs. Ill belive this when I do it first hand. You might even be able to get by ordering just a few needles as opposed to buying the DJ kit(which you really only need the needles from).