sluggish power pulse adrenaline 125

[benlad2012]

hey guys i've fitted an new exhaust, new cone air filter and changed my main jet to a 105 jet. i figured more air and fuel and a bigger exit for the gases would make my bike abit more responsive. Since i've done this i have more top end power (slightly anyway) and i know i'll loose some acceleration but in 1st it seems really sluggish! and at the bottom of 3rd gear too its almost as if i twist the throttle and nothing happens for a few mins then finally i get a response. Would changing my main jet to a smaller jet like a 100 improve this? or is there somting else i can do? any help would be great thanks ben.
P.s i've added a few pics of my bike too!
Photo0048.jpgPhoto0049.jpgPhoto0046.jpgPhoto0051.jpgPhoto0052.jpg

[spencer2004]

You probably need to adjust your idle mixture and raise the needle a notch. The main jet mainly affects throttle positions from 3/4 and up, the needle will have the most effect at 1/4 to 3/4 and the idle effects everything up to 1/4 throttle. A good start would be to adjust the idle mixture as it is the easiest to do; the idle mixture screw is the one on the bottom of the carb, it's really hard to access but you can make a tool out of a paper clip or a hack saw blade to make it easier. First get the engine fully warmed up then temporarily set the idle speed to around 2k using the screw on the side of the carb then using the idle mixture screw adjust the mixture to achieve the highest idle speed (turning it counter-clockwise richens the mixture (adds more fuel)), when done re-adjust the idle back to 1.4 - 1.5k.

The needle is attached directly to the throttle slide, when raised it allows more fuel to flow out of the carb, you can raise it to richen the mixture. I can't remember exactly how to do it but you have to remove the cap from the top of the carb, draw out the throttle cable, remove a snap clip then re-assemble with the needle 1 notch higher. It's pretty much the same for most carbs so just Google "mikuni needle adjust" or something.

Also make sure that you do not have a gasket leak at your carb. With the engine running spray some sort of flammable liquid on the intake (such as brake cleaner or WD-40) and see if the idle changes, if it does you have a leak and you probably need new o-rings. Don't get any sucked in to the cone filter or it will give you false results. Speaking of your cone filter you should waterproof it or your engine will suck in water when it rains.

[benlad2012]

cheers spencer, i've adjusted the idle speed using the screw on the sid of the carb and it seems to be alot more responsive but the idle is running quite hight. i'll have a look for the screw underneath you were talking about and try that. hopefully once i've adjusted that i think i'll be ok then. yh i saw your thread about your filter when you put a plastic bottle round it? i've been meaning to do that just havent got round to it. luckily its not been raining that much recently. i'll get it covered up soon tho thanks again very helpful!

[spencer2004]

As your filter is visible from the outside you would probably should find a more elegant way to waterproof it than a plastic bottle, you should get it done pretty quick though, if you get caught in heavy rain and it sucks in a large ammount of water the conrod could get bend since water dosen't compress too good.

[benlad2012]

where abouts is that screw you were talking about? i couldn't see any underneath my carb. and i'll make the air filter cover the next thing i do don't wanna end up having to fork out for the damage made by sucking water in!

[spencer2004]

There should be a brass flat head screw one the underside of the carb closest to the cylinder block. It does not stick out so it is hard to see.

20130626_215635.jpg

[benlad2012]

ah right ok i'll have another look cheers

[extr3m]

This is great guys. Got the same project on my Adrenaline with Yoshimura exhaust. Plus changing sprocket to 17 tooth.
Will post result here. ;-)
Thx btw

[benlad2012]

did you change your sprocket? i've got a 17 tooth sprocket but not had time to put it on yet.

[extr3m]

Ive put on 17tooth sprocket but didnt modify any thing yet. So my acceleration decreased, my top speed decreased from 72mph to 63mph.
Less fun but more economicaly. And my new sprocket rubed off the wires which goes next to it and my bike doesnt start anymore couze of the naked wires. rubis. gona fit my old sprocket.