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Project '98 FZX250 Zeal

Discussion in 'Your 250cc Projects' started by jakezeal, May 11, 2022.

  1. jakezeal

    jakezeal Active Member

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    Fair warning, essay below.

    Picked up a 1998 fzx250 zeal about a month or so back off a guy who had stored it in his shed for a while, first bike after getting my L's earlier this year. Had to have this one after test riding another and loving it at a dealer only to have him sell it as soon as I decided I wanted to buy it!

    Rode it home, rode for a couple of weeks until the local shop could fit me in for the new tyres (Pirelli Sport Demons) it desperately needed where I found out the seller had been bending the truth a little when he said he'd recently done oil/coolant/brakes/carbys. Shop sent me home with a list of things that needed immediate attention!

    When I got it there was fuel coming from somewhere in the back of the carbys, enough to pool on top of cylinder 1 and then spill off onto the oil pump/all down the coolant hose/pipe. Idle was inconsistent on choke when cold (and reluctant to start, would take about a minute trying different choke positions), then after a couple minutes riding I'd push the choke all the way in and it'd idle really low - around 1000rpm - until properly up to temp, then idle around 2000 unless I was riding it hard and then it would be more like 2200-2500 at idle.

    So far I have flushed radiator and refilled with fresh coolant, changed oil and filter, got a k&n air filter and cut it down to size (found the tip on a Facebook group), taken the carbys off and semi-dismantled them (got the float bowls off and cleaned them and the jets I could get to out, didn't get to the needle), tried to change the (cracked) intake manifolds to some from a FZR250 but the throttle fouled on the rocker cover because they're about 10mm shorter than stock, and played around with the idle mixture screw (all 4 carbs were set at 4 turns out) so it's not running quite as rich. Turned idle revs down to 1600. Managed to split the fuel hose at the petcock and spit petrol everywhere in the process today so ran out to get a new hose and a new fuel filter while I was at it - just got whatever the had at Repco and found a way to hook it up with the new hose.

    Took it out for an hour in the hills after putting all back together (lost half an hour after I put it all back together and forgot the airbox so had to take the tank off again) and it feels much... Cleaner? Throttle is a bit more responsive and doesn't seem to be leaking fuel out of the carbs any more (yet!) but there are definitely still some flat spots. Sometimes on opening the throttle pretty wide it'll hesitate for a second before the power kicks in, and power drops off completely at 12k rpm (stock redline 25 years ago was 14500.

    Bike is very fun to ride, and I know I'm in the deep end with learning to fix a bike where there are 4 tiny everything's instead of a single cylinder beast that would definitely be easier to tackle. I'm assuming that I've got the idle mix close enough now that it's a consistent 1600rpm at all warm temps (even after riding hard) to not need to keep fiddling with it, but am I going to do any damage riding it with these flat spots?

    Things I know I still need to do: find replacements for the intake manifolds that are all cracked all the way around (not cracked through, so not leaking), replace the fuel pump mount that's split, replace split clutch cable and lever (housing is split, lever wobbles a fair bit vertically), flush and bleed both brakes, get new grips. Also don't know if the valve clearance has been done, so need to either tackle that one or find a shop that'll do it.

    Things I would like to do: LED headlight insert for the stock mount, LED indicators, new mirrors (can't see great with the stock ones and the right one rattles like crazy), flatter bars (without going wider, the narrow bars are nice and I don't want to recable the entire thing), maybe a tail tidy. Kinda hate the rear end and don't envision ever using the pillion seat.

    Next time I'm doing work on it I'll be sure to take some photos! [​IMG][​IMG][​IMG][​IMG]

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  2. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    Welcome. It is going to be cold blooded coz it's a 250cc 4. Please read through the tech tips section in the forum and most of your problems have already been covered. You are a learner rider but you don't sound like a total noob when it comes to the mechanicals - worked on other bikes?
    I'm old, so I like bikes to have rear guards and seats. The new fashion of tail tidies and cafes makes me want to vomit. If you want to go down that path then please keep the original parts. First it will be worth a lot more as original, and second the bike will appeal to a lot more buyers.
    Cheers
    Blair
     
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  3. jmw76

    jmw76 Well-Known Member

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    Welcome.
    There is something satisfying about riding a screaming 250 x 4 as opposed to the more modern 1 and 2 cylinder commuters.
    I am addicted to the screaming banshee style engines.
    I seem to get more comments about my little CBR250RR than I do about my cbr900RR.

    Enjoy.

    Peter.
     
  4. jakezeal

    jakezeal Active Member

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    Thanks for the welcome both!

    Yeah, have had a pretty good look through for most of the info, would've never tackled it otherwise! Definitely going to get a rebuild for the carbys and will probably try to get new needles at the same time so it'll be all fresh. Don't worry, I'll rethink the tail tidy and seat - run it original seeing as it's all there and complete!

    The inside of a couple of the float bowls seemed really scaly and rough - is that a concern?

    Have done minimal work on cars but was a bicycle mechanic in a shop here in Adelaide for nearly 5 years so pretty confident with fiddly mechanical stuff. Never worked on a motorbike before this one!

    Still trying to make the riding position work but being such a small bike the bars are a bit too close for me to really sit in the seat, I find myself sliding backwards to get comfortable and then sliding forward under heavy braking. Anyone got a bar recommendation in an appropriate width, or should I just find something flatter with less sweep and then cut it down if need be?

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  5. Dingleberry

    Dingleberry Member

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    I personally like wide mx bars on my bikes. Something with very little sweep and relatively flat. That's spreads my arms (6'4 armspan) to get me into a more comfortable position without sitting upright with little bars.
    The inside of the float bowls doesn't matter but if any loose scale, just give it a clean up.
    I would recommend making a cheap carb balancer to get your tune spot on. Have a Google for homemade carb balancer. They consist of some clear tube, a board to mount on, and some joiners etc. Cost you less than $20 to do and well worth it.
     
  6. jmw76

    jmw76 Well-Known Member

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    Call me old school, but I still prefer balancing carbs by ear.


    upload_2022-5-13_9-44-30.png
     
  7. jmw76

    jmw76 Well-Known Member

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    I have gauge based synchroniser, but I find it easier and more effective to just listen to the intake hiss.
     
  8. jakezeal

    jakezeal Active Member

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    Gonna have to look into balancing them then I guess!

    After deciding I'd magically got the mixture screws and idle revs perfect a few days ago, yesterday at the end of the ride idle revs dropped down to 1400 and stayed there, and today after fiddling with the idle rev screw I got something I've seen others brjng up on these and FZRs - the idle climbs up to 3500 or 4000 rpm and stays there. If I let the idle rev screw out a quarter turn, it drops back down to 1500, but if I touch it again to get it up to 1600,just climbs on back above 3k.

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  9. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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  10. jakezeal

    jakezeal Active Member

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    Oh ****, so the idle screw acts on the throttle but the throttle only moves carb 3 and the rest move from that one? That would explain it!

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  11. jmw76

    jmw76 Well-Known Member

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    sounds like you might not have the carb balance quite right.
    When the balance is correct, adjustment of the idle speed screw should move all 4 butterflies in sync.
     
  12. jakezeal

    jakezeal Active Member

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    Had a crack at fixing the idle issue this afternoon - wanted to see if I could fix it without taking carbys off.

    New fuel line and filter routing has enough give that I can take the tank off and rest it next to the bike and run the engine - small win. Without diving into one of the existing forums about balancing while I already had the tank off and was in there, I decided to see if I could work it out so started playing with the adjustment screws (perhaps not my brightest move, but we'll see). With the engine idling around 1800, started with the central one between 2 & 3, and went one way - no change - started turning the other way until the revs started to change as I assume this meant carby 2 had begun to open the throttle. Backed off until revs went back, then repeated the process with the 2 & 1 screw and the 3 & 4 screw. Managed to go back in a quarter turn on the mixture screws with no discernable change to idle (all now at 3 3/4 turns out) and throttle response is quick and clean when opening.

    I'm going to take a minute tonight to go through the other balancing posts to compare my method to what I should've done, then ride the bike to work tomorrow and see how it rides.

    Managed to forget to take the side fairings off the tank before trying to lift it off the bike and snapped one of the mounting points in the process.

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  13. jakezeal

    jakezeal Active Member

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    Update: success! After a mishap with cheap jets I got some replacement mikuni jets as the stock ones are all chewed up by previous owner, and with them and the float bowl half of the litetek kit (it was all I hafld the guts to take apart) the little Zeal now runs better than ever! Couldn't help taking it out even though it was raining last night now that I have my bike back, had been out of action for a month. //cloud.tapatalk.com/s/62fadace5d41b/VID_33050106_031232_031.mp4

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  14. Why?

    Why? Active Member Premium Member

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    Am I doing something wrong, cant get sound to play
     

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