Fahren Posted August 20, 2009 Share Posted August 20, 2009 Is it worth ditching the airbox on my 87 FZ600 in favour of KN air filters?...the airbox lid is damaged and doent seal properly plus there a pain in the ass to get back onto the carbs. I need to replace the carb/engine inlet rubbers, i noticed only one air box rubber was actually fastened tight to the carbs the other 3 were barely covering the carb, no apparent gaps that i could see but no airtight seal either i would guess. I figure i would need to change the jets too anyone ever done this and know what size jets are required, also if it rains is that going to affect the bike too much. failing all that does anyone have a spare airbox for sale? Link to comment Share on other sites More sharing options...
barwell1992 Posted August 20, 2009 Share Posted August 20, 2009 Is it worth ditching the airbox on my 87 FZ600 in favour of KN air filters?...the airbox lid is damaged and doent seal properly plus there a pain in the ass to get back onto the carbs. I need to replace the carb/engine inlet rubbers, i noticed only one air box rubber was actually fastened tight to the carbs the other 3 were barely covering the carb, no apparent gaps that i could see but no airtight seal either i would guess. I figure i would need to change the jets too anyone ever done this and know what size jets are required, also if it rains is that going to affect the bike too much. failing all that does anyone have a spare airbox for sale? i would go with the kn filter but try and get one with a cover as they do get wet changing jets is easy just have a look at some diagrams and you will soon see i have no idea about ure bike thogh so carnt help there but if you want a quick fix then just get an original oir box Link to comment Share on other sites More sharing options...
Moderator Cynic Posted August 20, 2009 Moderator Share Posted August 20, 2009 Is it worth ditching the airbox on my 87 FZ600 in favour of KN air filters?...the airbox lid is damaged and doent seal properly plus there a pain in the ass to get back onto the carbs. I need to replace the carb/engine inlet rubbers, i noticed only one air box rubber was actually fastened tight to the carbs the other 3 were barely covering the carb, no apparent gaps that i could see but no airtight seal either i would guess. I figure i would need to change the jets too anyone ever done this and know what size jets are required, also if it rains is that going to affect the bike too much. failing all that does anyone have a spare airbox for sale? NO absoloutly fix the airbox, TTS tuned my GSX years back and they ALWAYS use the airbox where possible. That means anything upto and generally including race prep they only junk it when its either too restrictive which you would be surprised to find how far an engine can be tuned before that happens. Or the engine mods require big induction mods like turbo's and such, like drag bikes with nitros , Or the bloke paying the bills say's so, Pod filters only work efficiently at flat out. The airbox acts as a buffer to pressure waves caused by wind, riding at speed and the reflections off of the carbs themselves (the same tuning that affects an exhaust affects the carbs)etc and give a pool of calm balanced air that can be fed evenly to all cylinders at an even if not low temperature and pressure. It is also much better at protecting the motor from dust, water and general crap. The greater part of the crap a motor sucks in is rubber and that really messes with the internals. By all means fit a K+N element as that will give much better airflow but keep the airbox if even remotely possible. Your bike really will thank you. Link to comment Share on other sites More sharing options...
Moderator Cynic Posted August 20, 2009 Moderator Share Posted August 20, 2009 There are 2 on e-bay now search ' yamaha fz600 airbox' Sorry don't know the clickky (edit)Ahem, sorry didn't realise that the modern fazer was also an FZ dur. Link to comment Share on other sites More sharing options...
Fahren Posted August 20, 2009 Author Share Posted August 20, 2009 cheers guys...think i will either try and fix old airbox (previous owner broke the lid cos 2 screws were rusted solid) or replace with 2nd hand ebay job Just had the shock of my life 4 carb to engine intake rubbers £242 jeez thats rather steep! will need to do some online searching methinks...ebay aint got any! Link to comment Share on other sites More sharing options...
grizzlydan Posted August 20, 2009 Share Posted August 20, 2009 I have a 86 fz600 with k&n cone filters & can say that if you change to them up your jets by 2 sizes to stop overheating (too lean mixture), by the way the bike will have starting/running problems in wet weather til the bikes warms up & dries the filters. Link to comment Share on other sites More sharing options...
Fahren Posted August 20, 2009 Author Share Posted August 20, 2009 cheers Grizzly, if i do go the KN way it will save me time knowing the jets need to be 2x up in size, just cant beleive the price for the inlet rubbers...still i bought this bike as a bit of fun to do up etc...last couple of days its been running a little rough, it was alright when i went to Devil's Bridge on sunday (heheh beat a 600 bandit on the twisty bits ) I have the carbs off atm so will give em a good clean, intake rubbers are cracked on the outside and quite hard on the inside which points to replacement. Bike has started showing a reluctance to power past 80MPH last few days feels sluggish and also seems to have developed a vibration at same speed that ive not noticed before....on inspection of the airbox there seems to be a small amount of oil in there behind the filter is this normal?.....i know theres 2 pipes one that comes from the crankcase and the other is a drain pipe.. Link to comment Share on other sites More sharing options...
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