I have been posting on all the other related topic's in this forum but feel its time to start a thread dedicated to resolving my issues. Top To Bottom recount of service so far; Carbies have been stripped and cleaned (soaked for three days), Re-assembled with new airbox boots and orings. Replaced Air Filter and Oil Filter and oil change. Replaced chain and sprockets The problem is after riding for more then 5min's it cuts out whenever it returns to idle. I have to leave it at 5000rpm for it not to cut out. you can hear the fuel pump load then the bike run low in rev's and cut out followed by the noise of the feul pump again. If i pinch the fuel line before the fuel pump I can feel a random pulse, at the sametime you can hear the rev's change as though it is lumping small amounts of fuel (or) its restricting flow?? Through these forums I have found another issue; the drain for the carbi is blocked, could this also contribute to this issue Finally when it does cut out is smells heavy of fuel (rich) and if you can rev it hard or ride it hard you can hear misfire in the exhaust. It feels like vapour lock with the bike spluttering and struggling to create power. The only way around it so far is to leave the ignition firing for about 30sec's.. this is probably killing my starter motor and battery but the bike sometimes returns to a ruff and very low and random) idle.
The bike should idle for quite a while (minutes) even if the fuel pump stops, disregard fuel pump as an issue for this problem. It could be either float levels or idle mix screws or both. Have you checked that the choke is not stuck on? Idle mix screw location is on the top side of the carb accessed by taking the air box off (I think) and just near the rubber boot connector to the head. Looks like item 5 on the carb PDF file. Might have a cap on it, someone else may be able to confirm that. That blocked hole is the float chamber drain valve hole, turning that rusty looking screw at the lower right of the hole opens the drain. Handy to have unblocked but not essential. It could be unblocked by using a pin or a bit of wire.
If I put even the slightest amount of choke on it cuts out straight away. before i attempt any dissassembly I will run a treatment through, something to clean the carbi (Break up any hydrocarbon) this might solve my issues without pulling it apart.. If this doesn't solve it I will post some pic's up of my attempt of doing something with the float levels and idle mix screw's
Backfire on acceleration (on throttle) means your running rich (backfire on deceleration (off throttle) means your running lean), now that we know your running rich, we check the obvious, mix screw, float bowls, air filter, carbs etc. to see why there is more fuel (thats required) than air supplied. This could be due to lack of air (air filter, carb, mix screw, choke), or too much fuel (float bowls, injectors, high octane fuel (of which some doesn't ignite till its in the exhaust), etc) after all that you should have found your problem. Now lets check off your list ; carbs :tick: , air filter :tick: THis has probably not help but i tried. <!-- s --><img src="{SMILIES_PATH}/icon_smile.gif" alt="" title="Smile" /><!-- s -->
First run with fuel treatment (carb cleaner) is now complete. I only used a small amount of it in so it was not too concentrated in the tank. I ran it through for 110Km, riding it easy, holding revs and riding it hard 17-18000rpm. (still never letting the revs drop incase it cut out) To my suprise when I got home and let it idle it did not cut out!.. I was just about to put the stand down and ... blop blop blop blop burrrrrrrrrrrrrr (fuel pump left running).. IT CUT OUT. At least I have bought time to catch the idle before it cuts out by reving it back up again. I'm hoping after another two runs with the fuel treatment that I can get it to idle even longer before it cuts out. I was so impressed by this additive I have bought an oil treatment too, it releases sticky vavles etc. After I save up some money i will take it back for a tuneup (less rich and new spark plugs) So far, it has been a positive outcome with the fuel treatment so I will continue this course of action.. I will update the outcome soon.
Well its raining too much for a ride so I decided to let the bike idle for a few minutes to see if it has improved since last ride with its idling issues. For an experiment I decided to disconect the fuel pump to see what would happen .... nothing, infact it can start the same, run the same and cut out the same .... I think I might make a bypass of the fuel pump to see if it actualy restricts its operation in some way. while idleing the fumes from the pipe were white and you could hear it purbling as though it was igniting in the pipe. the fumes were strong too. could someone please show me a photo of the idle mix screw, so far I cannot find it .. remember its a 2kr.
The fuel pump is there for a reason - the lower half of the petrol tank is lower than the carbs and petrol does not run up hill - without it you will run out of fuel when the tank gets to about half full/empty.. Have a look at the fzr 400 manual, which is in english, for the location of the idle screw and presumably in a similar location - it is item number 20 on page 6-2 in this chapter <!-- l --><a class="postlink-local" href="http://www.fzr250.com/attachments/fzr400/05_FZR400_Service_Manual_Ch567.pdf">attachments/fzr400/05_FZR400_Service_Manual_Ch567.pdf</a><!-- l -->
Just a quick update for this thread. A friend showed me where the idle screw was and we cranked it up (about a 8th of a turn) and it's idle sounds alot less (diesel injected!) Its also stopped cutting out and is getting steady(er) and quicker with its power delivery. Honestly being a new rider didn't help with this bike. It wasn't until I hated everything about this bike that it started to come back to life. The reason is because I started to ride it like I was trying to rev it to death and it likes that. It still sometimes chokes, I dont know if its flooding or starving with feul but i do know if i spike the throttle a few times (CPR) it manages to keep going. (from froom froooom from from) It's unusual, the bike has its own personality and I swear I would be the only one who could ride it now. I like it now cos it sounds great and I nailed a new hyosung GT250R from the lights. I guess its all about getting to know the bike and my bike is an unsociable difficault clown with asthma and blood pressure problems but boy the last years of its life are gonna be a blast if i have anything to do with it!
<!-- s:roll: --><img src="{SMILIES_PATH}/icon_roll.gif" alt=":roll:" title="Rolling LoL" /><!-- s:roll: --> <!-- s:roll: --><img src="{SMILIES_PATH}/icon_roll.gif" alt=":roll:" title="Rolling LoL" /><!-- s:roll: --> <!-- s:roll: --><img src="{SMILIES_PATH}/icon_roll.gif" alt=":roll:" title="Rolling LoL" /><!-- s:roll: --> <!-- s:roll: --><img src="{SMILIES_PATH}/icon_roll.gif" alt=":roll:" title="Rolling LoL" /><!-- s:roll: --> Thats the spirit
