hi iam a new rider i brought a 1988 fzr400 this weekend however iam haveing a few problems can any 1 help? basicly around 3000rpm to 4000 rpm its got a flat stop b 4 and after everything is ok. its had the exup system removed and a micron end can fitted (sounds nice) still got the original manifold so with the exup valve not being there cauld this b my problem or is it just a case of eveything needs setting up ie carbs cheers ps its not got the 33bhp restictor on

Hi newrider,
I had a similar problem with my bike and it turned out to be the missing exup causing the problems. I managed to get a second hand rusted set of pipes off ebay with an intact valve and transplant it into my pipes which worked well. The bike now runs MUCH better with lots more torque off the line.

I guess you could tune the carbs to get around the missing valve but the easiest way would be to raplace it.
good luck
Si

yup - sounds about right.

Welcome to the forum though stick up a few pics (check the FAQ link at the top of the page)

hi thanks for the info the problam iam faceing now is i think the bit where the exup valve sits has been cut off so look like i will have to find some new downpipes at the risk of sounding stupid where does the exup valve sit on the downpips oh ya i will need a selonoid to great lol thanks again ps i will add some pics of my bike when i figure it out lol

hey newrider

first off...good choice of bike! . without an exup valve you lose loads of bottom end torque, you'll have to wring its neck to about 9-10k rpm to get it going. as to its location it is in between the downpipes and link pipe to the can on the lhs of the bike.

remove the cover and also check the alignment and the tension in both cables to the pulley...

to do this...

alignment...with the cover removed watch the pulley rotate when you toggle the engine switch on and off (i found it easier if working alone to leave the engine switch on and toggle the key while looking at the pulley on the lhs of the bike). there is a forked bit on the pulley and it should align with the hole at approx the 9 o'clock position on the valve cover. if it doesnt align with the hole then the cable tension is wrong. if you manually move the pulley fork over the hole and put a small allen key in there to hold the pulley in place you can then tighten the cables so its correctly aligned

also the cables should only have about 1.5mm of play in them. mine were to loose and i think it causes 'fluttering' of the exup valve causing power loss.

if that doesnt solve it you may have an air/fueling issue. there is a good guide for carb cleaning on: http://en.allexperts.com/q/Motorcycle-R ... ROBLEM.htm" onclick="window.open(this.href);return false;

if the bike hasnt been run for a while before you bought it then the petrol in the carbs will turn to a kind of varnish that can restrict fuel flow. if you do go down the carb cleaning route...dont seperate the carbs from each other or you will need to re-synchronize them.

also get yourself a manual...there a few pdf available for dl on this forum. also i found one on http://www.yamahaclub.com/forums" onclick="window.open(this.href);return false;

good luck

rich

oh yea...also, this is a great guide for exup maintenance

http://www.cartestsoftware.com/fz1/exupmaintenance.html" onclick="window.open(this.href);return false;

hi rich thanks for the help the problem i have is the exup valve has been removed had a look today and theres a blanking plate on there and all the cables and servo have been removed theres sum wireing under the seat so iam assuming the wires r for the servo so with this all missing wauld this b the cause of my flat stop at around 3000rpm tp 4000rpm have i got to replace it all or can i just get the carbs ajusted accordingly.the bloke a brought the bike off did it up as a project bike and i no he fitted a second hand engine and he removed all the exup system and some other bits and bobs iam loveing the bike apart from that 1 minor fault so like i said iam hopeing i will just need a simple carb clean and set up thanks again newrider

newrider wrote:hi rich thanks for the help the problem i have is the exup valve has been removed had a look today and theres a blanking plate on there and all the cables and servo have been removed theres sum wireing under the seat so iam assuming the wires r for the servo so with this all missing wauld this b the cause of my flat stop at around 3000rpm tp 4000rpm have i got to replace it all or can i just get the carbs ajusted accordingly.the bloke a brought the bike off did it up as a project bike and i no he fitted a second hand engine and he removed all the exup system and some other bits and bobs iam loveing the bike apart from that 1 minor fault so like i said iam hopeing i will just need a simple carb clean and set up thanks again newrider

If the bike is going to be a track animal, jetting the cabies is the way to go. If you're going to be cruising your local streets then you really want to stick the exup back in.
The fzr really needs the variable back pressure at low revs provided by the valve.

Hi Newrider,

Not sure if would be of help but i have a FZR400 3tj Servo, cable and bracket in the garage you can have. I'm sure someone on here could confirm if it is compatable with your bike, If it is then give me a shout, i'll send it over if you cover the postage.

Cheers

Lee.

buzzawak wrote:

newrider wrote:hi rich thanks for the help the problem i have is the exup valve has been removed had a look today and theres a blanking plate on there and all the cables and servo have been removed theres sum wireing under the seat so iam assuming the wires r for the servo so with this all missing wauld this b the cause of my flat stop at around 3000rpm tp 4000rpm have i got to replace it all or can i just get the carbs ajusted accordingly.the bloke a brought the bike off did it up as a project bike and i no he fitted a second hand engine and he removed all the exup system and some other bits and bobs iam loveing the bike apart from that 1 minor fault so like i said iam hopeing i will just need a simple carb clean and set up thanks again newrider

If the bike is going to be a track animal, jetting the cabies is the way to go. If you're going to be cruising your local streets then you really want to stick the exup back in.
The fzr really needs the variable back pressure at low revs provided by the valve.

Hmmn, it all make sense to me now. as my 3tj have been replaced with stainless steel system. have no ex-up. i do get this flat spot just between 3500-4000 rpm.