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Project FZR250 2KR 1986 is ready to go

Discussion in 'Your 250cc Projects' started by Why?, Nov 24, 2022.

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  1. Why?

    Why? Active Member Premium Member

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    History of the bike,

    It was a guys daily commuter until 2012 when it was put in the garage and left, last year during lock down he tried to get it going put some fresh fuel in the tank and it fired on 3 cylinders for a short period but that was about it. He could not keep it going.

    Got the bike to my factory on Monday arvo, 2 flat tyres, battery stuffed even with a charger attached could not get Zip out of the electrics.

    Today removed fairings and tank cover, purchased and installed new battery, replaced tubeless valves (perished) and inflated tyres (decided to get it going before replacing the tyres). Generally cleaned up the wheels and chain rear sprocket.

    Electrically the horn, lights and indicators work, indicator switch needs cleaning out and lubing. Motor turns over but could not get to fire, will check for spark on the weekend and possibly clean the carbies.

    I will also replace the plugs while I'm at it. Bike has potential.

    IMG_8432.JPG
     
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    Why?, Nov 24, 2022
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  2. Why?

    Why? Active Member Premium Member

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    It lives, jets were totally blocked, bowl full of crud. Managed to eventually get it started but had trouble getting it to rev, finally got it to rev to 6000 to 8000RPM but it was like it was starving for fuel so I'll replace the fuel filter and try again. Managed to ride it around the carpark in first gear. Also flushed and replaced the coolant.

    Now the down side, alternator/regulator does not seem to be charging was only getting 9VAC on the output of the alternator and 11VDC at the battery, when revved voltage only went up to 11.5VDC at the battery (Brand new battery).

    Also fibreglassed up the inside of the fairing where cracked they are now ready to go back on.
     
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    Last edited: Nov 26, 2022
    Why?, Nov 25, 2022
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  3. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Congratulations
    Charging system, check the reg/rect connection for arcing/burning and you can plug a 120+ volt globe into the 3 phases of the stator through the back of the reg/rec plug to see if it's outputting enough current to drive the globe

    Regulator/rectifiers are a known weak point
     
    ruckusman, Nov 25, 2022
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  4. Why?

    Why? Active Member Premium Member

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    Thanks for the heads up, I was going to unplug the alternator and measure what voltage it is putting out, I figured it maybe the regulator pulling it down as it it is putting out balanced voltages though very low while plugged in. If while unplugged its voltage increases I will replace the regulator. A job for tomorrow. But I am happy with the progress and the bike will end up quite good.
     
    Why?, Nov 25, 2022
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  5. neoncrypnid

    neoncrypnid Well-Known Member Premium Member

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    If you do decide to replace the regulator/rectifier, a good option is the MOSFET reg recs. Super efficient, runs cool, and I've never heard of one burning out. They are a bit pricey but there's some deals around. I'll chase up more information if you need

    Sent from my SM-G991B using Tapatalk
     
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    neoncrypnid, Nov 25, 2022
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  6. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    Make sure you test charging system with a fully charged battery.

    Stator test is easy. Disconnect from regulator, test resistance between all 3 wires. Should be the same. Any high resistance or open circuit is bad. Test each wire to earth - should be infinite resistance / open circuit, anything else is a short to ground on that phase. Last is AC voltage test, easy to do check AC voltage bewteen all wires at 5,000rpm.

    Sometimes when a stator is boderline or only fails when hot you need to load test it with a couple of batteries and a tail light wired in series with the phase you want to test.

    The stators on these are dry, they do not run in oil so easy to pull off and inspect. Right hand side cover. Also has crank timing marks on the flywheel.

    The regulators are body earthed, so make sure the regulator body and mounting bolts are free of rust/corrosion. Also clean the earth strap to frame/engine and main 30A fuse point.

    I've had one of these standard regulators fail on a Zeal and it was overcharging, blew the guts out of the regulator and killed the tacho, dash backlighting, every globe and the indicators. Not fun.
     
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    Linkin, Nov 25, 2022
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  7. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Measuring the actual voltage out of the stator directly and accurately is somewhat difficult as it's high frequency AC - frequency dependent upon engine revs, that's where an incandescent globe works, if it lights it will tell you there's both voltage and current.

    Static measurements; Measure resistance between phases first, then check no short to ground.

    As @Linkin pointed out - Regulator/rectifier needs clean ground to it's casing, they work by basically shunting excess voltage to ground.

    The regulator/rectifier is the likely culprit, but don't discount a poor earth, leaping to conclusions can be good exercise
     
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    ruckusman, Nov 26, 2022
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  8. neoncrypnid

    neoncrypnid Well-Known Member Premium Member

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    You could always swap a known good one from one of your working bikes and see if the voltage improves?

    Sent from my SM-G991B using Tapatalk
     
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    neoncrypnid, Nov 26, 2022
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  9. Why?

    Why? Active Member Premium Member

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    Regulator was the culprit
     
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    Why?, Nov 26, 2022
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  10. Why?

    Why? Active Member Premium Member

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    Getting there new seats should be here Monday, new fuel filter, regulator and fan thermostat ordered 6A86E1DC-06A8-451E-AC1B-23C8F6BB64C3.jpeg 960D1C6A-4A16-4BFC-A9BE-1DB531F4796A.jpeg E6BB807F-96E5-445F-BC27-3F6F61929834.jpeg
     
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    Why?, Nov 26, 2022
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  11. Why?

    Why? Active Member Premium Member

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    Seats arrived


    seats.jpeg
     
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    Last edited by a moderator: Nov 28, 2022
    Why?, Nov 28, 2022
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  12. Why?

    Why? Active Member Premium Member

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    IMG_8458.JPG IMG_8457.JPG Welded up the broken Instrument frame, decided to leave it the undercoat colour, just waiting on new fuel filter as it still starving as the revs increase.
     
    Why?, Dec 2, 2022
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  13. Why?

    Why? Active Member Premium Member

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    Put the carburettors off the parts bike on this today, the internals were very clean, starts and runs much better only issue is the bowls have a slight leak. Ordered a Litetek seal kit which should resolve issue. Still waiting on fan thermostat and tyres to complete this bike.
     
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    Why?, Dec 8, 2022
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  14. Why?

    Why? Active Member Premium Member

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    OK just waiting for new fuel filter and Idle is way to fast, idle adjust screw is not even touching and throttle cable has some slack .
    Apart from that here she is. Have not painted bike and it is as original as possible.

    IMG_8471.JPG IMG_8472.JPG IMG_8473.JPG IMG_8474.JPG
     
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    Why?, Dec 9, 2022
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  15. Why?

    Why? Active Member Premium Member

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    Expecting an air leak to be causing the fast idle (though very smooth) I replace all the carburettor intake rubber manifolds with good ones but this made no difference, all the throttle butterflies look completely shut. Starts easy runs fine just idles at 3500 to 4000 RPM. Help please.

    I did think of putting a fine smear of gasket gu between the manifold gaskets and the head but I hate the stuff. Do you think this may fix it?
     
    Why?, Dec 19, 2022
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  16. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    No, it won't work. I regularly replace old manifolds that have been gooped and are still leaking. None of the stuff used is fuel-proof.

    Have you confirmed air leaks? Spray a solvent around the manifolds. If the revs move up or down it confirms a leak.

    In any cause you should vacuum balance the carbs, just be aware if you replace the manifolds you'll need to balance again.
     
    Linkin, Dec 19, 2022
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  17. Why?

    Why? Active Member Premium Member

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    Best place to get a set of vacuum gauges?
    Are these OK $60.00 on ebay?

    s-l1600.jpg
     
    Last edited: Dec 19, 2022
    Why?, Dec 19, 2022
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  18. jmw76

    jmw76 Well-Known Member

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    I purchased a set, but found the gauges particularly difficult to use.
    The concept seems ok, but the gauges have no damping and are near on impossible to get reliable readings. I tried tweaking the valves on each gauge, but it was not particularly successful. You could possibly insert a small restrictor in each line and get better results.
    I found the old rubber tube to my ear was far more effective. I have successfully balanced the carbs on all of my bikes by ear.

    Peter.
     
    jmw76, Dec 20, 2022
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  19. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    I've got a set from decades ago, very much like that.
    Those look better as there is what appears to be a restrictors at the gauge, without the restrictor the needles bounce like crazy.

    Plus it has the various fittings all there and the price is right.

    Alternatively, make yourself a liquid mamometer - use heavy weight oil 75WT or heavier transmission or diff oil works, add some ATF for colour
    4 holes into a re-sealable jar with rubber grommets to seal the hose
    I recently had to get 4 more restrictors as mine were MIA.
    They're used in fish tanks for the air pumps and the air stones to regulate the air pump flow - got some from Pet Barn I think it was. I tried using the silicone tubing that came with it, but it was too flexible and collapsed with the intake pulses.

    So some oil in a jar, 4 holes with rubber grommets to seal, 4 tubes [clear PVC is rigid enough for the task] and something as a backing to hold the hoses to see the measurements.

    Some details and a youtube video
    https://www.2fiftycc.com/index.php?threads/fzr250r-3ln1-project.10903/page-3
     
    ruckusman, Dec 20, 2022
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  20. Why?

    Why? Active Member Premium Member

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    Appear to have air leaks where the manifold joins the head, when I spray carburetor cleaner near the base the revs increase. I need to make up some new gaskets.
     
    Why?, Dec 20, 2022
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