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fxz250 Zeal Running issue

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by sjh, Apr 16, 2009.

  1. Hey all,

    Thought id throw a spanner in the works.

    My bike runs fine until i have been riding for 30mins or more, quicker if there is bad airflow.

    then the bike starts to miss at around 6,000rpm. The longer you ride the bike starts to miss lower in rev range, and im 'powerless' from 4k to 6k then from 2k to 6k.

    BUT as soon as i can get the bike to crawl past 6k rpm all hell breaks loose and its like nothing was wrong. - that is until i have to change gear and the revs drop below 6k again.

    hopefully that makes sense.

    any advice? have cleaned carbies, and flushed fuel tank, using goood fuel.

    The bike will sit at idle fine, but under load the above happens. If i walk outside now, it will start fine and rev freely through the rev range.

    its not due for a service, but its no fun to ride like this its a real prick to ride when its playing up.

    thanks guys

  2. 250's don't do anything below 8k rpm anyway so it sounds normal. :LOL: Someone will no doubt anwer you with a definate solution... but until them I would clean/repace the air filter hoping that could be the issue. If it's filthy then it can cause the engine to miss and bog down when you give it throttle. I'd replace the sparkplugs too as if a clogged air filter has caused it to run rich, then I guess it's possible they've fouled too.

    Is the bike overheating at all?
  3. g'day seany,

    air filter is aok, will check the sparky's.

    The bike isnt overheating

    I had this reply on another site 'your cdi unit is suffering a from power surge try to check the output power if it is stable.'

    i have no idea what the guy is talking about. :) so if anyone knows...

  4. It's most likely that the plug leads that are the problem then. :)
  5. 1) Does the miss occur at all throttle positions, or only some throttle positions? (EG closed, cracked, 1/4, 1/2, 3/4, full?)

    2) Are your high tension leads rubbing on anything (or against each other?)

    3) Is your choke sticking open - if you pull the clutch in and close the throttle, does the bike die?

    4) If so, can you do that in your driveway, pull the plugs and describe their condition

    30 minutes sounds far too long for the problem to be directly temperature related.

    Also, if the CDI recieves a surge, the Regulator would be cactus. things lose their smoke when the regulator goes, even more at higher RPMs, so that seems unlikely. Any surge protector would still kick in at higher revs, and except in special circumstances, it would be happening from startup. I'll happily eat my words if I'm proved wrong though.
  6. Ok, just a quick update.

    I have just thrown out the old battery, and replaced it with a new one. Also picked up a trickle charger.

    Took the bike for a couple of small rides, havent had a chance to take it for a good one yet.

    answering the last questions;
    1. misses start at 6,000revs, and if i kept riding the miss started coming in earlier in the rev range.
    2. Leads are aok
    3. the choke works no worries, doesn't die if its full in and the bike is warmed up.
    4. will pull the plugs out this weekend and check em out.
  7. have the carbs be overhauld not just cleaned, i had a zeal and the performance was all over the shop, the carbs needed to be rebuilt... i was running a gutted exhaust and no aircleaner, so it should run very lean, but was infact the opposite, black fart on full throttle all the time and 8-10L/100km :shock:

    it did fly though but had 2 distinct flatspots at about 8k and 11k but pulled hard to 14k and even with me 120kg on it smoked my mate 80kg on his bmw650 lol
  8. Check the following:

    - Air filter
    - Amount of oil (2 liters max for Zeal).
    - Check that the throttle cable is adjusted correctly and that the handle grip isn't catching on the end piece of the bar.
    - Check that the choke isn't out.

    My guess would be the throttle cable... too much slack. I had a similar problem but fixed it by adjusting the throttle cable.

    Below are some diagrams to unsure you put the parts back where they belong. If you require the complete parts diagram eBook for the Zeal, simply PM.


    If people are having troubles finding part diagram guides for their Yamaha, send me a PM and I'll see if I can locate a copy to suit your bike.
  9. If you could send me this it would be great! (cant PM yet.. not enough posts)

    email: scott@activelifestyle.com.au

    thanks mate.
  10. Year of manufacture?
  11. Will do soon. Couple of days mate.

    Unfortunately I am slowed (bigpond) so sending a file this large will take hours.

    I'll post here once I've sent that off to you.
  12. thanks mate! no rush