2005 Scorpa SY250

Discussion in 'Trials' started by j__h, Jul 20, 2013.

  1. Twin-shocker

    Twin-shocker Long timer

    Joined:
    Jan 28, 2012
    Oddometer:
    1,673
    They crack due mainly to vibration. If you are careful to mount exhaust properly, and keep the mounting bolts tight I doubt you will have any problems. As to that hole, if it was my bike I would simply dent the damaged area in a little to provide more clearance, roughen and clean with acetone, then JB weld it. Its pretty difficult to TIG weld used exhausts nicely, as oil/crud tends to get drawn into the weld area, which makes a good job less than easy. For non stress repair, I think you would be much better off with JB weld.

    Both exhaust boxes on the SY tend to get get blocked with unburnt oil relatively quickly, and its a good idea to find a good full synthetic oil and run this at 80:1, which will greatly reduce the speed at which the boxes get clogged. Later bikes had a modified middle box, which improved performance quite a bit, as the earlier one seemed quite restrictive. The UK Scorpa importer built his own bikes based on the TY Yam motor used in the Scorpa, and found that carefully designed and made intake and exhaust systems, meant performance that was quite a bit better than the production machines.
    #21
  2. j__h

    j__h Adventurer

    Joined:
    Mar 29, 2013
    Oddometer:
    13
    Welding complete, could not get the inside fully oil free this made the job difficult but it seems to be good. It did not want to close the last bit and thus the blob. Hopefully it is all sealed.
    [​IMG]
    #22
  3. Twin-shocker

    Twin-shocker Long timer

    Joined:
    Jan 28, 2012
    Oddometer:
    1,673
    Looks like a pinhole to me.................I would JB weld it to make sure you dont need to remove it again.
    #23
  4. j__h

    j__h Adventurer

    Joined:
    Mar 29, 2013
    Oddometer:
    13

    I know what you are seeing, I inspected that before putting back on and it does appear sealed.

    Although now the bike does not want to idle, with or without choke. Need to get back into the carb and also start using ethanol free fuel and a fuel filter.
    #24
  5. Sting32

    Sting32 Trials Evangelist

    Joined:
    Oct 27, 2009
    Oddometer:
    1,497
    Location:
    Minneapolis, Ks
    JH, the ethanol (AND THE CHEMICALS THEY USE TO KEEP THAT FROM SEPERATING WATER) eats away the fiberglass. at the VERY MINIMUM, suggestion is to fill it up to ride, without ethanol fuels, then empty tank after that last ride that day. ALso insert a good filter in line to the carb, keep extras for easy change.

    some tried to coat tanks, varying results though, because of ethanol eating away at the fiberglass!

    Good luck, I have 2 fiberglass tanked machines, but I no longer store the bike with ANY gas in the tanks! not even a DAY...

    but I can get "ethanol free fuel" at a pump that sells only ethanol free unleaded... But the problem most PEOPLE that get gas trying to get non ehtanol fuel is they exist on the same pumps that pump the trash fuels... What i mean is, can have a 12 foot hose full of ethanol (that was pumped by previous customer). So if you have one hose but 3 selections on a pump, pump 5 gallons into the car, then fill you "mixing gas can" or buy race fuels, or buy Av gas, those are your choices...

    Just fyi
    #25
  6. Twin-shocker

    Twin-shocker Long timer

    Joined:
    Jan 28, 2012
    Oddometer:
    1,673
    The Scorpa tank looks like nylon2 or hdpe to me..............its not fibreglass. TK carb seems to work well enough, but its a nightmare to take on and off, so strip, clean, and careful rebuild would be a good idea I guess.
    #26
  7. j__h

    j__h Adventurer

    Joined:
    Mar 29, 2013
    Oddometer:
    13
    Update:

    The weld is holding, absolutely no oil is coming out. I also opened up the carb and cleaned out some passageways most notably the pilot, whent on a 15 mile adventure and some easy obstacles to get a better feel of it so apparently the carb cleaning was successful, no idling issues. There is no ethanol free fuel from the pump around me, but I have found a few sources where I can get ethanol free race gas that I will probably be using going forward.

    Unfortunately, it appears that I have developed the very common split in the weld at the far rear of the center box, so back to the welder for me. I suspect that this will be much easier than the puncture.
    #27
  8. exman

    exman amateur-enthusiast

    Joined:
    Jul 17, 2011
    Oddometer:
    17
    Location:
    Belgrade, Serbia
    Does anybody know the effective way to clean the exhaust boxes, mine is clogged too. I heard about pouring the gasoline in to dissolve the oil residue, but I wander what could happen once the hot exhaust gases pass trough again.
    #28
  9. motobene

    motobene Motoing for 44 years

    Joined:
    Mar 9, 2013
    Oddometer:
    1,793
    Location:
    Wichita Mountains SW Oklahoma
    Here's how I do it. I burn out the oil. I use a small oxy acetylene torch with cutting tip. I start a fire in the muffler, then shut off the fuel (acetylene) and let the oxygen flow, sometimes hitting the oxygen lever for a directed boost. The trick is to get a flame front started, then carefully monitor the temperature as the front progresses deeper into the muffler. You don't want the inside to get so hot it melts the perforated metal stamping that overlies the oil soaked fiberglass, and it'd hard to see in there. It needs to be hot enough to carbonize the oil.

    This method is effective, but it is a polluting mess that is skills sensitive and can take hours to do carefully and well. If you lack the skills and patience, don't do it.

    A MAPP gas torch can do it too, but you really have to put the heat to it, and the torch will use up much of the available oxygen that otherwise would maintain the flame front.
    #29
  10. ericm

    ericm Been here awhile

    Joined:
    Sep 12, 2002
    Oddometer:
    654
    Location:
    Santa Cruz Mountains, California
    Is it safe to burn out an aluminium muffler box?

    It did it on a TY250 mono pipe and it does make a very stinky mess.
    #30
  11. motobene

    motobene Motoing for 44 years

    Joined:
    Mar 9, 2013
    Oddometer:
    1,793
    Location:
    Wichita Mountains SW Oklahoma
    "Safe" always depends on the 'loose nut behind the wheel.' Any tool or technique can be damaging. That's why I put in caveats when I present one.

    The technique works, but does has some risky of suddenly melting the perforated sheet if you are not quite good at monitoring pulses of heat buildup. Especially with aluminum, because aluminum will just suddenly give way without much warning. Aluminum melts at around 1220 F and steel is more than 2X at 2700 F.

    And oil soaked mufflers are louder and reduce performance a bit by lowering the resonating volume.
    #31
  12. usedtoride

    usedtoride n00b

    Joined:
    Apr 14, 2014
    Oddometer:
    2
    #32
  13. motobene

    motobene Motoing for 44 years

    Joined:
    Mar 9, 2013
    Oddometer:
    1,793
    Location:
    Wichita Mountains SW Oklahoma
    This is how to buy a used trials bike. Find one like this one!
    #33
  14. j__h

    j__h Adventurer

    Joined:
    Mar 29, 2013
    Oddometer:
    13
    Yes, it appears I do have your old bike. Your story matches what I heard from the person I bought it from (minus the cheating part but that would be expected to have been left out given who it was purchased from). Also, yes the extra fenders were included.

    As for the bike, yes it has been treating me well. Having quite a bit of fun on it and am considering doing some local events.

    I assume you were able to determine it was your old bike from the fork guards and nylon fender bolt?
    #34
  15. usedtoride

    usedtoride n00b

    Joined:
    Apr 14, 2014
    Oddometer:
    2
    well the shift lever(blue in scorpa), clear tail lamp lens plus other stuff, did it come with fan hard wired? I recd the switch after she got the house, still have the extra air filter and hex for the frt axle, hope to get montesa (nonrepsol) if they import into us again, oh well win some you lose some, good luck dude.:clap
    #35
  16. j__h

    j__h Adventurer

    Joined:
    Mar 29, 2013
    Oddometer:
    13
    Fan was hardwired but I purchased a new thermostat and have it installed (guy I bought it from did not mention that in his ad), fan works as it should now. Bought two new air filters, the hex key for the front axle, and some other spares also. Thanks, hope you can find an even better bike soon!
    #36