Wont start my cbr 400rr 1988 wont start have clean fuel in tank spark from the plugs and smells of petrol been stood for a while drove it back from my freinds house three weeks ago and now nothing. cheers any thoughts willl be helpful

most likely the fuel. if your using the petrol that was in before it stood it could be that. clean tank and card add new petrol. take out spark plug ( check for spark ) and check the end . if its black clean that too

how old is the fuel in the tank ? fuel goes off after 5months !! or it dould be contaminated with water or dirt etc , recomend cleaning the tank and removing the carbs and stripping and cleaning the jets etc !!
has the bike been unused for a long time ?
check that all spark plugs are sparking and check the compressions of each piston ! 100 psi or more is correct for each one , if less then the rings or the valves need investigating !
if you have any more information it will help me !
thanks Paul ...

The internal combustion engine is quite simple. All you need for it to run is compression, fuel & a spark to ignite it. I'm not saying it'll do 40 MPH but it should start & run. If it doesn't then one of the 3 elements is missing.
You need the following - sounds stupid but it wont work if one of these is missing.
1. PETROL - fill the tank to be sure. If its a 4 stroke just petrol. If its a 2 stroke petrol & 2 stroke oil mixed or top up 2 stroke oil tank.
2. Fully charged BATTERY. Clean connectors on battery tops
3. a SPARK at spark plugs. Clean them while they are out. If no spark look for dodgy coils, plugs, HT leads, triggers.
Look for air leaks in fuel line - if bulb does not go hard you got an air leak. Does it smell of petrol? check for leaks in fuel line & around carbs, look for perished fuel line, loose clamps or if they are jubilee clips, they could be too tight, crushing the anti-syphon valves at the primer bulb. loosen them until squeezing the bulb scoots fuel out then re-tighten JUST enough to stop fuel leaking.
Does it turn over? - then battery ok & not seized
Does the choke operate? operate lever & confirm things turn properly on carbs.
Once its started you can fine tune it but it needs to start first!!

Sounds like you have trash in your tank or line. I've seen this happen with atv's even though you believe all your fuel going in is clean, stuff can still get in unknowingly to you. I've seen a floating honey bee in a cars fuel tank cause all kinds of problems like that. Owner spent countless hours and dollars replacing sensors, solenoids, and come to find out the dead bee would stay afloat normally, but when the fuel pump pulled it into the screen, the fuel flow would either be minimal or totally stop it all together. Pull that fuel line off and turn your petcock valve on and off to see if fuel comes out good or partially. Your bike may be getting fuel fine during low speed and idle, but upon demand when more fuel is needed to accelerate, the flow is restricted somewhere and it starves the carbs. Hope this helps.

check the spark plug. if was working fine before i would start there and work your way back from that. clean the spark plug and test on a meter top part to the tip on the electrode. then check the lead then the wire/s into the coil pack

FIRST CHECK SPARK PLUGS CLEAN OR REPLACE THEM REMOVE OLD PETROL FROM TANK AND REPLACE WITH NEW
IN SOME CASES THE JETS IN THE CARB GET DIRTY THIS MIGHT NEED ATTENTION

Try a new spark plug, that would be your best bet, if that fails charge your battery and heck with a volt meter that it is 12.5V if that still does not work replace your ignition coil, they can go at any point in time :)

I would first fill the tank with fresh fuel especialy if the bike has stood for any length of time also determine as to wether or not fuel is actualy reaching the barrrels remove the spark plugs & check if they are wet or dry if they are found to be dry open the drain plugs on the carby float bowls if fuel runs out of the drain it must be asumed that your broblemis carburation & will require the carbies to be removed stripped & cleaned this will involve the removal of all the jets the float & the needle & seat once these have all bean cleaned thoroughly [compressed air is usefull for this part of the operation] &reasembled return them to the machine &

Hi there, try this sometimes the stand switch can make the bike not work if has got rusted at the back.and check or replace the coil., then check if you are getting a spark from the plug by putting the spark plug on top of the head. The next thing is if the bike turns over but not fire up, you need to strip down carb and clean jets, also check petrol value under the tank If you have a book it will go through this step by step. good luck.

you say its see its been serviced if i was you i would buy new plugs if that doesnt work try cleaning carbs and fuel filters and as to starting a 4 stoke they usualy need full on choke in cold weather when you buy plugs get a hotter rated plugs /before you try above take out spark plug/s and brush end that goes into engine with a small wire brush clean well then warm plugs with lighter or burner and replace then try to start bike