Good Jetting Info
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junkmail10000
(5/14/02 4:21 am)
Aftermarket Kerker Exhaust and JEtting Q's
so i've got my hands on a Kerker slip-on (the old one, with specific bandit 400 application). Before i install it, just a few questions.
Is it mandatory to rejet after installing the can? At this point, I'm mostly considering installing it as a cosmetic/aural enhancement (my stock pipe is black, heavy, and a bit scratched up, and i'm looking for some whup-whup-whup to annoy the neighbors), and I don't have the time or money to futz with a jet kit.
I'm not too concerned with increasing HP, but am worried that the can would cause my bike to run too lean (causing something horribly bad to happen?). FYI, i've got a K&N air filter installed, and their literature recommends installing a jet kit if it is coupled with an aftermarket can, but i'd like a second opinion.
any enlightenment would be greatly appreciated.
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400FOREVER
(5/14/02 10:14 am)
jetting
I've put in a Dynojet kit to cure what I thought was a problem. It ended up being worn o-rings in the carbs. I can't stress this enough on these 400's. If it starts fouling plugs, idling poorly or running bad at part throttle, replace these. Also get bowl gaskets/seals. I don't know if the reformulated gas or alcohol in the gas causes these problems but you'll beat yourself over the head trying to diagnose the problem. Been there done that.
As far as jetting run it stock and see how she behaves. You won't do harm unless you do a top end run for more than a few seconds. Nothing beats a dyno run to get your main jet sorted.
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BEG
(5/14/02 1:15 pm)
Re: jetting
400forever, i wanted to know what problem you were referring to. i'm having problems with starting my bike. it doesn't want to start with the electric switch almost everytime. if i don't try to start the bike for maybe a week or two, it'll start right up with no prob. but as soon as i kill the engine, it won't start at all. i can bump start it sometimes after that, but sometimes even that fails. does this sound familiar to you or anyone!? if it does, please, please give me a remedy for this. i can't ride if the prob isn't solved. thanks so much for your time. ~ b.e.g
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400FOREVER
(5/14/02 6:30 pm)
jetting
Beg, the problems I experienced were rich running, gas coming out of the overflow tubes and fouled plugs. It would start fine if it didn't sit long. When it sat 8hrs-12 gas would run into one of the cylinders and when you hit the starter it would turn maybe a quarter crank turn and stop. I had to hit the starter about about a dozen times to finally spin the motor. Hydraulic lock big time. But like I said rich as hell. As long as the motor was revving and use fuel it ran great. It was like riding an older two-stroker, no power until the revs went up then BAM acceleration.
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psr123
(5/20/02 4:30 pm)
Re: Aftermarket Kerker Exhaust and JEtting Q's
The fellow that owned my Bandit before me tuned it at the dragstrip. He found that after shimming the needles to improve midrange, the main jets had to be dropped to 99's (from the stock 103.5's) to get best power at top end. I was skeptical, until I read an article in Motorcyclist by the fellow that makes the "Factory" jet kits. He said that several late-model bikes were jetted too rich in order to make up for the leanness of the needle settings (for smog purposes). In my case, the bike then went to my friend's ex-wife, who let it sit until the carbs gummed up and it had to be taken back to the dealer. The dealer returned everything to stock. Now I have the bike. I also have a brand-new Kerker slip-on. (Thank Goodness for Ebay & PF Cycles). My plan is to shim the needles up, leave the stock jets in, and hope that the Kerker will lean things out to an optimal level. I know what kind of trap speeds my friend was running, so I should be able to compare my results with his. (There's a dyno near me, but that's $50 a run; the strip is $10 for all day...)
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junkmail10000
(5/21/02 4:01 am)
Re: Aftermarket Kerker Exhaust and JEtting Q's
psr123: that's EXACTLY the sort of info i was looking for. i'm actually the other fella who bid on that P&F auction, so i'm in the same boat you are right now. please update on what you find out. i've got so many other things to deal with (new tires, chain, sprockets, radiator) before i stick the exhaust on. don't want too many variables at once.
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junkmail10000
(5/21/02 4:04 am)
Re: Aftermarket Kerker Exhaust and JEtting Q's
on a bit of a tangent, there's a yosh full system on ebay RIGHT NOW for $400. too rich for my blood, but maybe somebody here would be interested, i hear it's got a killer whup-whup-whup to it.
really don't want to start a bidding war amongst board members, just wanted to inform you guys, since the buy-it-now price is $450, and if it's gonna go at all, it's probably gonna go at that price.
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f155mph
(5/21/02 4:27 pm)
Jetting
Hey I got a Kerker from ebay too. It look very nice. I have the same question too. I want to jet mine but I don't want to spend $100 for a jet kit. I jetted my Gs500e without a jet kit and it runs great. So does anyone here know what Main jet, Pilot, and the number of shims I need for the needle to make it run good. I also plan to get a set of K&N.
thanks
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psr123
(5/21/02 6:17 pm)
Re: Jetting
The standard shim for raising the needles is .020" thick. I'm in the process of doing mine now, so I'll let you know how it works out.
If you go with the K&N pods, lemme know how that works. Everyone on this board (and my friend who tuned at the strip) says that the stock airbox w/ a K&N replacement filter is the way to go. They say that pods (or no filter, just open carbs - as a test) kill the power. I find that hard to believe, as airboxes do not tune the intake path length (they're a common plenum), although a well-designed box can smooth flow into the carbs.
To once again quote the guy from "Factory", he claims that the Bandit runs too cool in stock form to carburate properly. He races a Bandit 400 and runs a 190 deg. thermostat from a CBR600 vs. the stock 170 deg. 'stat. I may try this once I'm familiar with how the bike runs stock.
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psr123
(5/26/02 3:59 pm)
Re: Jetting
Correction: Stock jets are 102.5, not 103.5 as I stated. I just took my carbs apart this morning, and the rubber seals around the float needle are shot. More waiting.....
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Ambulance Chaser
(5/28/02 1:25 pm)
Re: Jetting
Hey there I believe that I bought a kerker from the first wave that P&F was selling on ebay, anyhow I am very pleased with how it looks, I also painted the stock pipe with high temp. aluminum. It Looks great pics to follow. Also I had added a k&n filter and have purchased the jet kit from factory. I am in SLC and have the following settings. 97.5 jets the needles are clipped in the third position which I believe is one down from stock. I also purchased a synch tool which is well worth the 40.00 I paid for it. The bike runs awesome. I put dunlop 207's 120/60 r17 and 160/60 r17 on the bike and I am so impressed with how it handles. I also tightened up the rear two clicks and have vortex clipons on it. I also have painted the wheels black. Anyhow this bike get looks. I love the way it runs.
Safe riding
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f155mph
(6/8/02 11:55 pm)
Carb adjust
I finally got the exhaust on today. I put two washers under the needle and I set the air mixture screw to 2.75 turn. Well my bike do idle now. At first I forgot to set the air mixture screw so there was no turns on it. When I hit the gas the engine stay rev for few seconds before droping back down. With the air at 2.75 the engine would die down then go up. But not it will not idle. So how should I fix this?
Thanks
Topic: Good Jetting Info (Read 12550 times)