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RG 250 - fuel runs out of carbies like a waterfall

Discussion in 'Technical and Troubleshooting Torque' started by linerunner, Aug 16, 2006.

  1. Ok, bit of background - 85 RG250 with blown head gasket
    Had in shed for a few years, thought it was either going to the wreckers or I was going to pull it apart and do it myself even though I dont know what the hell Im doing. So I pulled it completely apart, cleaned it and put it back together again.

    Well, the engine has been rebuilt now, new head and base gaskets, powervalves serviced, new coils etc (I had to take it to MR motorcycles in SA) because I kept snapping bolts with my dodgy torque wrench.

    Anyway, I put it all back together, gave it fluids, charged the batt and went to try and start her up on Sunday. I turned the fuel switch on and fuel started gushing out of some tubes in the carbs. Ive got some pics at bikepics.com where you can see the tubes -


    its the tubes for BOTH carbs, the greenish ones at the bottom as well as the black one to the right of the choke, below the idle screw.
    When I took it apart I had to take the tops off the carbs because im a retard and couldnt get the throttle cables off any other way, which meant the carbs were in two parts for some time - I thought Id put them back together again right!!

    I know that this is a difficult problem! I dont even know where to start! Its like they fill up with fuel and just overflow but I dont know what that could be.

    Any advice would be greatly appreciated!! Im totally stuffed!!
  2. Umm obvious question first, the carbie drain taps aren't open by any chance?
  3. check your float needle is seating correctly and set your float levels to whatever it says in the manual
  4. I remember having an RG250 a long time ago.. fast lil bikes.. i had issues with the float needle in one of the carbies getting stuck, so fuel will come out of the overflow.. i give the carb a tap or 2 with fingers or something harder and it fixed itself..
  5. Yeah, try tapping the carb bowls with a plastic screwdriver handle, hopefully the needles have not got rubber tips and haven't dried out...
    Oh, and put a fuel filter in the fuel line if you haven't got one, who knows what crud is in the tank!

    Regards, Andrew.
  6. OK, Ill try tapping them and see what happens. Just gotta hope I dont set myself on fire

    If that doesnt work I might have to rip em out and get them looked at I suppose
  7. OK, I gave them a tap with a bit of wood and a hammer and that stopped the leak so thanks Paul and Typhoon! Unfortunately it still wont turn over.

    The battery was totally dry so I filled it with water hoping that because its a 2-stroke it wouldnt matter so much but now I think the next step will be to get a new batt and check to see if theres a spark.

    Any suggestions?
  8. Try buying some battery acid and refilling the battery with that. It's a cheaper option than a new battery, and it MIGHT get you going for a month or two, but treat the battery as being on borrowed time if it works.

    Regards, Andrew.
  9. if the battery was flat on my old rgv250 the little bugger wouldnt run properly even with a jumpstart
  10. A lot of batterys develop a "memory" after going flat and will never reach full charge again.

    I think the reason is~ a fully charged battery, the lead plates are disolved into a type of phosphate in the acid and dischargeing transfers the phosphate back to the lead plates.

    Once the water is evapourated, leaveing the lead plates with less lead so the battery will never reach full charge again.

    My chemistry is shocking, may be total bull *hit.
  11. Lead - Acid batteries don't suffer from battery memory.

    Chance are when the battery dried out the sulphate reduced the lead plates completey to lead sulphate.

    You will need to have a look at the lead matrix and see if its in good condition. If it's white, your matrix has turned to sulphate, and its time for a new battery.

    No amount of sulfuric acid will fix it.
  12. Linerunner, if its an 85 bike it will most likely run on leaded petrol. What are you running it on now? Out of curiousity, how do you alter an older bike to run on unleaded?
  13. I ride a 1980 kwaka Z250B.

    Even if it does run on leaded petrol, you can use unleaded in it.

    The lead is just there to prevent detonation on compression.

    My car has run for the last 10yrs on regular unleaded and it was built in '77

    It is a 2-stroker though, so i'm not sure how lead would affect that.
  14. 2 strokes don't have valves, and most of the reason for running lead through a car is that they don't have hardened valve seats and they die in the arse due to them not getting enough lubrication.

    I had a GT250, which is a 2stroke parallel twin also from 'zuki and it ran perfectly fine for 5 years on 95RON unleaded. No pinging, no carrying on, and the engine was just fine and dandy when I sold the poor girl.
  15. actually, tetra-ethyl lead like what is used in petrol, was found to peripherally protect the valve seats. The lead in the fuel reduced detonation.
    The valve protection is just an added bonus that was found out later.
  16. the lead in fuel is mostly their to lubricate, when a vehicle is changed from leaded to unleaded they put in hardened valves and valve seats.
    its a 2 stroke, has no valves and therefore isnt such an issue.
    also the fact it uses 2-stroke oil to lube...
  17. And the octane rating of the uber leaded fuel available was around 98RON.
    Moot point, lead helped valve seats too - the only reason not to use it in some cars is cause it kills the valves, ASSUMING YOU CAN OBTAIN FUEL OF THE RIGHT OCTANE (or detune the vehicle).
    Running unleaded fuel of an appropriate octane in lots of vehicles does no damage (including some cars) and it definately isn't a problem in two-strokes ASSUMING YOU HAVE THE RIGHT OCTANE FUEL IN THERE (or detune).
  18. OK. cheers for all the replies - the bike however is still sulking in the shed.

    N20 - the battery is COMPLETELY white inside. I would guess that means its totally f-ed. Typhoon, Saintan - Id like to try the acid coz Im a tightarse but I dont think that will help. The bike hasnt been started in a few years so I dont have much faith in it.

    The RG has never been run on leaded. Ok thats a lie. Once I was mega hungover and got confused by all the silly names and filled it with leaded. Poor bike hated me for it - it sounded like it was choking and couldnt breathe properly - as if it was on the verge of death. I took it home and emptied the tank all over my front lawn trying to take it off and ended up with a big dead lawn. So premium seems to work the best. Also petrol makes you itchy.

    This Sunday Ill be checking the spark so Ill keep you all posted.