Tuning-how to??

[Slipin]

hi all .. have finaly got my GSXR400's CDI rebuilt and solved all my woes the bike has had the carbs rebuilt befor i brought it. and have noticed a flat spot around 8-10k mark .. was wondering how to go about tunin it and if a carb vaccum gague would help in tunning the higher rev range ??...

cheers for any help

[Nigel]

I have no idea bro but glad to see you're almost ready to get out there! There's a racecraft coming up on the.. 17th? It's the monday following this monday. Hope it's good to go by then!

[Lord Farquaad]

nah, vacuum gauges would be pretty pointless

[Slipin]

cheers semi.. and yuggert you betta fracken belive im ready for the 17th!!!!! been waaaaaaaaaayyy to long between drinks !! and yeah seems all those probs i had bfor were the CDI ... so as off about 5pm this arvo shes ready to rock!! the bike's good to race but would be nice to get that flat spot out.. you going up 2 king's on the wknd?? apparintly im one of the flagy's for sat and sun ..got me u beut pit padock pass for my car and my free ticket that even has the terms OFFICIAL on it!! scarry i know!! i have the power!! first time ever up there for an event besides Race craft ... so should be good

[druu]

I'd do the carbs again and check what position the needle is at on the clip (if it's adjustable that is). If you're running stock jets, etc. make sure your needle position is centre.

[Nigel]

I'm hoping to get down there for a little bit to see some of the racing, should be bloody awesome, but I have exams on monday and tuesday so i may not be able to make it, and if i do i'll only be around for a little while.

There's also a champions trackday (google them) on the 13th if you're keen bro, I won't be going unfortunately (fucking exams again). Seeya on the 17th though, if all my stuff arrives - still waiting on tyre warmers and slicks.

[Slipin]

mmm 17th... monday aye is it a public holiday at all mite not be going up otherwise

[Slipin]

I'd do the carbs again and check what position the needle is at on the clip (if it's adjustable that is). If you're running stock jets, etc. make sure your needle position is centre.

wasnt me who did the carbs the first time so mite be a bit out off my league and i dont think the jetting on it is standed.. the flat spot's not major but it's deffinatly there ... heard horror storys about the GSXR400 carbs and trying to tune them so as ive just got the bike going again im a bit hessitant to pull it apart again .. fiddeling with the screws i can do .. but how much and wich ones and will it go bang if i twist the wrong way..

[druu]

Ahh I see. Well 8 - 10k would be the midrange of the bike which would be pointing to the needle height (ie clip position) so maybe play around with that.

[Slipin]

well i have know idea what your talking about . or what it is but i will look it up in my japanise manual and suss it out .. cheers for the info though dru ..

[RAVENGSXR]

The needle on the left is the factory or standard setting moving the circlip down makes for richer moving up makes for leaner

[Slipin]

ahhhh ok .. not so hard .. cheers... can i do this without taking the carbs off??

[Slipin]

and am i right in saying all the carbs should be at the same level??

[House]

Also, not all stock needles have adjustable clip position.

Ones that don't may be shimmed with tiny washers however.

[druu]

Yup, all should be at the same level. You should be able to do this without removing the carbs from the bike but it will be a little fidgety, just make sure you don't drop any screws anywhere! If it's bogging, try to raise the clip one notch on the carbs to lean out the midrange. If it's worse, go the other way.

[Slipin]

cheers boyz .. doesnt sound to hard .so will def give it ago in the next week or 2

[rgvlee]

Ahh I see. Well 8 - 10k would be the midrange of the bike which would be pointing to the needle height (ie clip position) so maybe play around with that.

nearly... substitute 'mid range' with throttle position, and couple that with a chart of the jets for that carb vs throttle position and you're on your way. Throttle position, not rpm, is the key to working out what is causing the problems. As a general guide, up to 1/4 is pilot, 1/4 to 3/4 is jet needle and 3/4 onwards is mains.

[druu]

I stand corrected. And here's a pic to redeem myself:

[Slipin]

ahhh cheers lee.. every little bit helps

[Mockery]

ah excellent, I've been meaning to look for a copy of that chart.