Kerker 4-1 help?

[van crawford]

I RECENTLY INSTALLED A KERKER 4-1 ON MY 2005 VMAX WITH A STAGE 1 JET KIT. IT SPUTTERS/MISFIRES THRU THE MIDRANGE ONLY. MY MECHANIC TALKED TO DYNOJET AND THEY SAID MY SETUP OF 1.5 INCH BAFFLES AND A STAGE 1 JET KIT WOULDN'T WORK, BUT IT WOULD WORK GREAT WITH 2 INCH BAFFLES. DOES ANYONE HAVE ANY INSIGHT? CAN I STILL RUN A STAGE 1 JET KIT WITH 2 INCH BAFFLES? WILL I HAVE TO UPGRADE TO STAGE 3,5, OR 7 JET KIT? IT PULLS HARD AT LOW AND HIGH RPMs, JUST STRUGGLES THRU MIDRANGE. ANY COMMENTS OR SUGGESTIONS WOULD BE GREATLY APPRECIATED, THANKS.

 

[Sharky]

Best bet is head over to the intro section mate....folk around here like that....then ask Mr Morley......

 

[Fire-medic]

I RECENTLY INSTALLED A KERKER 4-1 ON MY 2005 VMAX WITH A STAGE 1 JET KIT. IT SPUTTERS/MISFIRES THRU THE MIDRANGE ONLY. MY MECHANIC TALKED TO DYNOJET AND THEY SAID MY SETUP OF 1.5 INCH BAFFLES AND A STAGE 1 JET KIT WOULDN'T WORK, BUT IT WOULD WORK GREAT WITH 2 INCH BAFFLES. DOES ANYONE HAVE ANY INSIGHT? CAN I STILL RUN A STAGE 1 JET KIT WITH 2 INCH BAFFLES? WILL I HAVE TO UPGRADE TO STAGE 3,5, OR 7 JET KIT? IT PULLS HARD AT LOW AND HIGH RPMs, JUST STRUGGLES THRU MIDRANGE. ANY COMMENTS OR SUGGESTIONS WOULD BE GREATLY APPRECIATED, THANKS.

Most people on here are going to tell you, 'fuhgedaboudit' for the Stage 1. Sean Morley of Morley's Muscle can send you his kit which should work well for your application, and restore your midrange. He is available to discuss your setup once you decide to bin your Stage 1, which probably isn't worth the time to mess w/it, from what others post about it. Baffles for your bike? I thought you said it's a 4/1? Souldn't you have one baffle?

I have a Dynojet Stage 7 and UFO 4/1 which my mechanic has made work well for me, it idles OK, doesn't run hot, and pulls well right through to redline. I still have VBoost too, which makes it a lot easier to synch the carbs. If you want to, you can unplug the VBoost motor when it cycles to the 'full-open' position when you turn your key on, and then you just re-plug it in when you want to synch the carbs.

 

[van crawford]

Thanks, I meant baffle not baffles.

 

[dannymax]

I have a Dynojet Stage 7 and UFO 4/1 which my mechanic has made work well for me, it idles OK, doesn't run hot, and pulls well right through to redline. I still ave VBoost too, which makes it a lot easier to synch the carbs.

I have the same carb set-up with v boost and a Kerker.....very strong, doesn't lay down anywhere.

F/M, do you feel the v boost when it opens, or do you leave it open all the time? (except for sync'n)

 

[Fire-medic]

I have tried the VBoost both ways, and unfortunately, had the rear intake cam split in two pieces which I am sure you read about, now fixed of-course, and when I re-installed my fresh valve-job engine and new (used) intake cam (thank-god for parts engines for spares readily-available!) I re-plugged the VBoost motor, so I have it working again, instead of open all the time.

Frankly, when I went for a ride yesterday after installing my Jap big-bore sportbike (canister -only) exhaust onto my UFO headers, I didn't really notice the 'surge' I get w/the stock exhaust. The VBoost was active. I might need to play-around a bit to see the effects of plugged-in vs. unplugged VBoost. When I was using the full UFO Dragstar 4/1 w/either the 'balogna-cut' "muffler" or the UFO megaphone instead, I did have a distinct sensation of the VBoost working. I tried it w/the full UFO & unplugged VBoost, but decided I liked the throttle response better w/it working. It also seemed like it started better (easier) w/the VBoost working, though I am not sure if that was just some subjective issue. It didn't take as-long to crank & start. You barely needed to hit the starter, but then again, I have a "Vanity Battery!" Li-ion, you know!:biglaugh:

 

[dannymax]

Interesting, I was asking cause I don't feel the boost kick in on the 1260 either....certainly not an issue as the bike pulls like a freight train anyway.

 

[94 V-Max Rider]

I RECENTLY INSTALLED A KERKER 4-1 ON MY 2005 VMAX WITH A STAGE 1 JET KIT. IT SPUTTERS/MISFIRES THRU THE MIDRANGE ONLY. MY MECHANIC TALKED TO DYNOJET AND THEY SAID MY SETUP OF 1.5 INCH BAFFLES AND A STAGE 1 JET KIT WOULDN'T WORK, BUT IT WOULD WORK GREAT WITH 2 INCH BAFFLES. DOES ANYONE HAVE ANY INSIGHT? CAN I STILL RUN A STAGE 1 JET KIT WITH 2 INCH BAFFLES? WILL I HAVE TO UPGRADE TO STAGE 3,5, OR 7 JET KIT? IT PULLS HARD AT LOW AND HIGH RPMs, JUST STRUGGLES THRU MIDRANGE. ANY COMMENTS OR SUGGESTIONS WOULD BE GREATLY APPRECIATED, THANKS.

Stage 1 jet kits don't work well with the V-Max. Put the jetting back to stock, except for going up one or two sizes on the main jet. Start there and see how it runs. If you're running a K&N filter, or modified the air box in any way, you may have to address any or all of the following depending where you're having an issue(s):

Idle mixture adjustment.
PA 2 air jets.
Shimming the [stock] needles.

I say this assuming that you haven't drilled the slides, changed the springs, and/or checked the float depths.

 

[Fire-medic]

Interesting, I was asking cause I don't feel the boost kick in on the 1260 either....certainly not an issue as the bike pulls like a freight train anyway.

Yeah, that's pretty-much my feeling, I have a strong pull right through the 6000-7500 rpm area, and beyond, and am not as-aware of thr surge from the VBoost as I was w/the stock exhaust. And once 8000 rpm's shows on the tach, it's only a moment until the needle is sweeping past 9000+ rpm, and it's time to shift. I have a big Autometer tach & shift light I am wanting to install, but I just haven't been able to get to it.

 

[van crawford]

Thx 94 Vmax Rider and everyone else for your ideas/suggestions, really appreciate it.

 

[NHVmaxpower]

I had a stage 1 in my max & took it out & went back to stock . She now purrs like never before

 

[one2dmax]

Remove the stage one as noted. Install one or two sizes DOWN on the main jets. OR, get a stage seven or our Muscle Jet kit (our kit will have more midrange).

Sean

 

[94 V-Max Rider]

Remove the stage one as noted. Install one or two sizes DOWN on the main jets. OR, get a stage seven or our Muscle Jet kit (our kit will have more midrange).

Sean

Sean, for some reason I was under the impression that it's common practice to increase the main jets with the stock needles, and to decrease the main jets with a Stage 1 or 7 jet kit. I'm really interested in this because my brother is running a kerker 4-into-1 that was was way over-jetted (if I recall it had 175 main jets when he bought it). I installed 157.5 mains, put the stock needles in, and it runs pretty damn good except for an occasional burble right off idle in cold weather.

 

[van crawford]

Thx Sean

 

[one2dmax]

If changing needles ONLY then you would want to use a larger main jet on a stock needle then an aftermarket needle. But, it's not that easy. The jetting between the stage seven and our jet kit is a little different. With our kit and the same needles you would use a slightly larger main with our kit.

With the stage seven vs our kit with the stock needles (not many use them anymore) you would need a much larger main with our kit.