Kawasaki Vulcan Forum banner
1 - 8 of 8 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter · #1 ·
Hi I have a question on what starting point to rejett my carb. I have Vance and Hines pipes and deleted all emissions stuff airbox and put on round open air filter my main jet is 138 and pilot 45 my elevation is above sea level 722ft in Canada temp here get up to around 30c in summertime. If anyone could help be appreciated just a starting point. Also my needle clip was set a two from bottom. Would a 170 main jet e to big? And say a 48 or 50 pilot? Thx
 

·
Registered
Joined
·
682 Posts
Hi JW,
  • Have you considered a DynoJet kit for your bike?
  • From what you said about the needle clip position, I would guess that the stock needle has already been removed.
  • A step up on the pilot will likely be necessary. The 50 with 1.5 to 2 turns out probably good.
  • A 170 from a 138...that is a HUGE jump on the main.
  • No doubt the flow mod you have done will require a major step up. The biggest change is the open air filter. You mean like K&N or you went full on open cell foam type filter?
  • You must have a good job to afford all that gas your bike is gonna start consuming.
  • You will need an assortment of jets to find the correct one. To just say "Oh Yeah, a 170 will be perfect" just isn't realistic. Jetting is a trial and error process that some find fun and others frustrating.
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #3 ·
Thx for the info and it’s becoming more of a pain in the butt lol. I’m actually using one of them spectre round filters deleted everything else air box and stuff I maybe should of not into this haha I’m mechanical guy but with a air ratio gauge installed still can’t figure this out yet. I put a 42 pilot in runs around 13.9 or 14 idle but when I give it throttle it just is in the 17 ratio and pops like heck.. tried 4 different sizes of jets so far nothing seems to fix when I give it throttle. Thinking something else is wrong maybe with carb?
 

·
Registered
Joined
·
682 Posts
  • Operating it that lean can melt spark plugs and pistons.
  • Do you maybe have an open vacuum port on the back of the carb? Or a 'T' fitting missing a hose?
  • You recognize that you should be seeing some change, so then something is keeping it full of air or there is a general lack of fuel in the carb or fuel being supplied to the carb.
  • If you have the 170 main, put it in and see what response you get.
  • I have seen in a web search a Jet manufacturer comparison chart. I'll see if I can find it again.
  • FAQ Jet orifice hole size Mikuni, keihin, dynojet - Jets R Us
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #5 ·
Wondering if I should just put the cross tube back in run the stock filter again just keep everything else deleted. I capped off the back at the top of carb where all the emission stuff connected. Hooked everything else up the only other line was the one to the side of card by choke but it never said cap or anything that one. It runs down to bottom of bike.
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #6 ·
Backing plates are in sealed good so not sure. Unless I’m missing something simple I can’t figure it out. I only run bike tell it warms up then see what it does shut it off when testing. But ya throttle gives me nothing but troubles on all different main jets. Idle is little rich but nothing horrible.
 

·
Registered
Joined
·
682 Posts
  • I would look into a DynoJet kit or ask around for some larger jets for the carb
  • The richest main that Kawasaki lists for that bike is a 142. But that takes into consideration that the bike is stock. Yours isn't
  • If you could get something like a 155 or 158 Keihin main. The 158 would be a 15% increase (from .053 to .061 hole size)
  • Locate your carb model number on the side and then Google main jets for it. There has to be some used that you can buy.
  • I wouldn't give up on trying to increase your bikes performance.
  • It will be a great learning experience, you can say you did it yourself and, you may be able to offer someone else some good tips for similar projects on similar bikes.
  • The line on the side of the carb sounds like your bowl vent. Without a pic can't be sure. You definitely don't want that plugged.
  • Like I said before, trial and error.
  • Have you searched the forum for 'Rejetting VN1500' or 'Carb setting after pipe install VN1500'?
 

·
Registered
Joined
·
682 Posts
  • The DynoJet kit comes with a DJ140 as the largest main which according to most sources is = a Keihin 152.
  • So if you don't want to or can't get the DJ kit you can look for a used Keihin 152 and 155.
  • The DJ140 is recommended for a K&N high flow and aftermarket exhaust
 
1 - 8 of 8 Posts
Top