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Re: Following on from my "3tj cdi post" such terrible runnin

Posted: Thu Aug 18, 2011 7:41 pm
by MarkT
Sorry!!!!just had a forum member pm me and should leave it like it is as it should be ok as it is with mane a touch of enrichment. Am I missing something obvious like plugs or something? Cant afford anything for a while now but am very confused ?
Mark. see you tues nick lol

Re: Following on from my "3tj cdi post" such terrible runnin

Posted: Fri Aug 19, 2011 9:21 am
by Evilchicken0
STOP !!!



Hammer time, du du du du, du du.
Now that's out the way ...

Leave these new carbs alone for now. Open up your carbs and write down the settings (jet size and where the circlip is on the needle) and put them all back as you found them . Only then open the new ones and note those settings too.
Then get the pipes.
This way you know where you are and where you need to move your carbs to.

Re: Following on from my "3tj cdi post" such terrible runnin

Posted: Fri Aug 19, 2011 9:34 am
by MarkT
Cheers mate!

Re: Following on from my "3tj cdi post" such terrible runnin

Posted: Sun Aug 21, 2011 10:32 am
by bendy3
Hi all, I dont think the problem will be the exup valve if it has been taken out and if it has I would disconnect the servo motor aswell. I race fzr 400s and have never had problems with running low down with no exup. I think the problem with the bike has got to be the carbs if you can hold the throtle wide open and the bike bearly revs then surely theres a problem with the slides on the carbs either sticking or not lifting with the vacuum for some reason. I would check the diaphrams for any holes or not sealing correctly, hence the bike goes at high rev's when the vacuum is stronger lifting the slides. Has anyone messed around with the lift holes on the base of the slides, sometimes people drill them out to make the slides lift quicker.

Image
An extract from the FZR 400 Race kit manual
I have a pdf file of the Race Kit manual if anyone's interested.

Re: Following on from my "3tj cdi post" such terrible runnin

Posted: Sun Aug 21, 2011 4:14 pm
by MarkT
Thanks for that, it has been a carb day today!
How on earth do you line up the Allan key to do the carbs up? I have spent two hours on it but I just can't seem to see or feel where they are? Also I want to change one diaphram, can I just remove the outer sealing ring and peel of the old one? Does the new one fit easy?
Also I have to many pipes, I can account for them all bar one, it is a big pipe that comes straight up from the crancase and I think it is a breather hose but can't see where it connects as there already a small breather pipe that comes from the air filter?
Thanks

Re: Following on from my "3tj cdi post" such terrible runnin

Posted: Sun Aug 21, 2011 4:42 pm
by MarkT
Found where the breather goes! What do forum members think of bendys post?

Re: Following on from my "3tj cdi post" such terrible runnin

Posted: Sun Aug 21, 2011 5:38 pm
by Taggyd
Be careful if you disconnect the servo. If the cdi hasnt been modified it will only
rev to about 4k was told its a fault signal of some form. Had this happen on my race bike when i first had it
with a standard cdi and no servo.
Get the carbs sorted and just try it. You wont know till you have a decent set of carbs to use.

Re: Following on from my "3tj cdi post" such terrible runnin

Posted: Sun Aug 21, 2011 5:50 pm
by MarkT
Thanks for the input, I know have a different set of carbs on I just can't do up the clamps!

Re: Following on from my "3tj cdi post" such terrible runnin

Posted: Sun Aug 21, 2011 6:21 pm
by sportspromatt
you need a extra long allen key, about 6inches,
or if you have a cheap set, not ideal, straighted it, and use pliers to grip it as you tighten it,
its quite a reach to get in, a small standard allen key will never reach, from what I remember there is a small gap in the clamp, to allow the rubber inlets to sit into this gap, this is the angle of the clip.
once carbs are fitted
gently heat airbox rubbers, either radiator or hot air, NOT hot water or flames?

hope new carbs sorts the problem out!

Re: Following on from my "3tj cdi post" such terrible runnin

Posted: Sun Aug 21, 2011 8:09 pm
by MarkT
New carbs (sort of long story) now twice as bad. Put it back how it was but the needles were definitely different really runs bad now