Rejetting to suit new exhaust

[conan]

Hi All,

I've never really done any sort of tuning-y type stuff before and I guess this is about as basic as it gets but I need some advice on how to proceed.

Basically I have fitted a delkavic system to the bike. It runs fine with the baffles in, but with them out my bike has gone from a bike that never turned any heads at all, to getting two compliments on the sound in a week from people at traffic lights and several more people oggling the pipes. I like it, other people like it, it must be good.

The downside is that it is gutless above 90 and really has to be pushed to reach 110 and it has all but lopped 15-20mph off of my top speed. Obviously I don't really need to go that fast but I do/did once or twice a week. Also to me it indicates that it isn't running right.

So firstly the easy option would be has anybody fitted the Delkavic 350mm oval pipes to their divvy and jetted to suit? If so care to share the correct jetting?

Otherwise how do I go about jetting it correctly to suit the pipes? I guess if I am going to go down that route I will stick a K&N filter on it too. Is it a case of buy a bunch of jets and trial and error or is there a standard formula to work it out? Do I need to get the bike dyno'd first? Is it a job best left to the professionals and if so how much will that cost me? yadda yadda.

Thanks

Conan

[neilmud Lord Protector]

Put the baffles back in & dont go over 70MPH its antisocial yobs like you that give us all a bad name

Neil

[conan]

ummm, It's purely for track use, officer, honest!

[CD]

My 900 had Delkevic headers and collector with Beowulf tri-oval cans. The baffles were ordinary 47mm universals bolted on with spacers so they sat neatly inside the very large bore outlets. The bike was certainly more lively than with the standard silencer cans and carb jetting was untouched.

The MOT guy loved its sound and passed the bike with no advisories.

[HRHpenfold]

Jun 15, 2013 9:57:33 GMT conan said:

Hi All,

I've never really done any sort of tuning-y type stuff before and I guess this is about as basic as it gets but I need some advice on how to proceed.

Basically I have fitted a delkavic system to the bike. It runs fine with the baffles in, but with them out my bike has gone from a bike that never turned any heads at all, to getting two compliments on the sound in a week from people at traffic lights and several more people oggling the pipes. I like it, other people like it, it must be good.

The downside is that it is gutless above 90 and really has to be pushed to reach 110 and it has all but lopped 15-20mph off of my top speed. Obviously I don't really need to go that fast but I do/did once or twice a week. Also to me it indicates that it isn't running right.

So firstly the easy option would be has anybody fitted the Delkavic 350mm oval pipes to their divvy and jetted to suit? If so care to share the correct jetting?

Otherwise how do I go about jetting it correctly to suit the pipes? I guess if I am going to go down that route I will stick a K&N filter on it too. Is it a case of buy a bunch of jets and trial and error or is there a standard formula to work it out? Do I need to get the bike dyno'd first? Is it a job best left to the professionals and if so how much will that cost me? yadda yadda.

Thanks

Conan

this explains jetting, its for the triumph twins, but the principal is the same!

Carb Jetting Info 2007.pdf (325.71 KB)

buy some jets in a range say every 5 points upwards of standard, buy some shims(small washers) in .5 thicknesses and some o rings

effectively you tune using the mixture screw, if it's still to weak, add the shims, if still to weak up the jet to the next one, start again until it's right,

it is of course easier done on a rolling road, but possible if time consuming to do it at home

[kawasakiinit]

my fzr 400 ran way to rich when i put an open can on it and lost loads of mid and top end ,with that i dropped the needles one notch to lean it out a little and wow what a difference . if you have loads of carbon build up on ya outlets its too rich normally . best thing to do is a dyno run to set up properly ,that way you see where its fueling wrong at what revs etc ..

[CD]

My 900 with Delkevic headers and collector never needed any jetting changes.