noob & new fizzer - engine trouble - couple of questions

hey guys,

i just bought a 1990 fzr (3ln)(3?) its my first bike and im still learning to ride, but ive been having some trouble with the engine. It runs great when the bike is cold, goes up to 20k no problems. Once the bike is warmed up and you stop for example at an intersection and then attempt to go anywhere the bike chokes, doesnt die just plugs along. You have to rev it up to 8 -10 and lightly let out the clutch before it will do much, it revs fine just has no power, feels like its running on one cylinder. My uncle has taken the bike for a ride and has had the same problem so i dont think its just noob reving. ive noticed this problem has occured before, something to do with a rich bike and the exup system. i have drained the fuel tank (lovely brown globs came out) so then replaced the fuel filter and spark plugs. the plugs were quite black and the guy in the bike shop commented the bike was running rich as buggery. another thing to note is that the bike has an aftermarket exhaust with a huge outlet for a bike of this size, could this not be causing enough back pressure and when the bike heats up making it run rich and choke?
when i start the bike it doesnt need any choke, so sounds rich to me...

This being the case how can i check the tuning of the bike? i know its supposed to be 3 turns out, but without knowing which screw to turn i decided not to touch it? Can anyone please describe the process of doing this? and also how to clean the float bowls? would adding a small pipe down the exhaust with a flange at the end give me enough back pressure in the exhaust?

short history of the bike, it has basically sat around doing nothing for i dont know how long, i bought it off someone who didnt actually ride it, and knew next to nothing about bikes, good price, but she needed a clean...

i would like to do an oil change on the bike, what is the best oil to put in and how much does she take?

the bike has a 140/70 (battlax) tyre on the rear, which needs changing soon (battlax) is this a good tyre? i know the recommended in 130/70 is it best to stick with this? how will the 140 affect her?

um also the bike doesnt have a fuel pump, should i get one?

i think thats it, thanks heaps this forum is great!

if i may also say so i think the fzr is an awesome bike, not too many of em out there and u can beat those toy boy racers! woo

 

thanks guys

when i cleaned the tank out i had a good look inside and all was clean, when i last filled the bike it was a way below reserve, and it cost 13 dollars something, with the price of fuel being about 1.30 i guess that means about 10 litres

the bike has done an unguaranteed 30 000 ks

also the problem gets worse on an incline?

in terms of the exup system, i know where it is, and have checked the servo, which does its reset so i assume its working, would it be worth taking the lower exup system off and cleaning it? checking its position? i do admit the bike sounds better than i would expect for a 250 could have been tampered with...

i remember seeing the rain in spain post, so i will check that out and clean up the carbs and float bowls

does anyone have any tips for repainting coroded aluminium?

 

just looked at the rain in spain post and the pics are gone! <!-- s --><img src="{SMILIES_PATH}/icon_sad.gif" alt="" title="Sad" /><!-- s -->
did anyone save them or know of other posts that have them? rain in spain 2 still has pics?

 

ok ive taken the carbies off and drained the float bowls, a small amount of grit was left at the bottom of the jar... i then attempted to take the covers off the float bowls, and only managed to get one off!! ergh, ive allmost rounded the head on one of the screws and another one is starting to give... am i doing something wrong? (yes im using the correct screwdriver) someone mentioned something about heating up the aluminium cause it heats faster and then they will come off easy? going to get a thin cutting blade and see if i can put a notch in the top and remove with a flat screwdriver.

the bowls looked ok, no major grit, there was a bit tho, and upon close inspection you could see more in the corners, and in obscure places, does this affeect it? i will also grab some carby cleaner.

also tried to take the exup system off, and could get every screw out except that last one! i could find a hex wrench to fit! if anyone happens to know the sisze of it that would be great and i can go pick one up or something...

thanks guys

 

haha ok i get what your asking now last time i filled the tank it had just gone to reserve, so when its back to just on reserve i will let u know ks (reset the odo as per habit)

managed to get the exup off, looks clean (well black but spins ok) and evidence of it running to full extents.

bought 8 new screws for the carby (hex heads) so i will give the hammer drill a go and see if that helps...

 

ok, managed to find an old impact driver and got them off! (only had a flat head so used a hacksaw to notch the tops, worked a treat) wow, the carbies were terrible! particularly under the diaphram, you can tell the bike had been sitting for some time, as there was a line of scum where the levels of liquid were...

also took the housing off which the needle butts up against? there was one odd screw (not brass, home made) and they had done a shocking job! and had tried to realign with washers and that, and i dont think would have come close... i couldnt find anything brass myself (i live in a rural area) but the local mower come motorcyle enthusiast managed to rustle something up for me (steel) and ive drilled it out myself with a drill press looks quite good and is very close to the original... (incedentally it was going to cost $40! to get one shipped from sydney, catcha!)

im going to give the carbies a good clean with carby cleaner, and reasemble then see how it goes... can anyone help me with tuning? ive allways wanted to tune the bike myself is this possible?

thanks guys

 

that would be great, i may even have a friend with one of those gas pressure thingos?

 

ok carbs and clean as a whistle (exup is clean too) and shes all back together...
i think it now has highlighted the problem, she doesnt sound nice at all, if u open the throttle right up it chokes at about 4 and lags, blows smoke and revs up, sounds rich to me! smells rich, feels rich. hope u guys agree
so i think its tune time!

 

ok, i have no idea how to set either of these! the idle screw is set right (the big one in the middle) are you talking about fuel mixture screws? which ones are these?
what do i change to set the float heights to 14 mm?
and what do you mean by resync?
sorry to be so daft!

 

found the 'how to' section of the page couple of questions about the carbs tho, the "carbs???" post details the carb setting, ie main jets 100 etc etc what does this mean? is this a measurement, or what?

found how to check float levels... couldnt find how to alter them...