Jump to content


  • Content Count

  • Joined

  • Last visited

About scifi

  • Rank
    Advanced Member

Previous Fields

  • Bike

Profile Information

  • Location
    N Wales

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

  1. scifi


    The welded up hole was most likely caused by the clutch basket finger exiting the chain-case. As there are many ears on the friction plates, I don't suppose the loss of one will be noticed. The irregularity might actually help to avoid the plates sticking together. The only downside is that the clutch may now be out of balance, but as it revolves 3 times slower than the engine, it might not be noticeable. Hope you manage to get a replacement from someone who has parts for TYs.
  2. scifi

    Novice question about adjusting preload

    You want the Falcon 'Speed Bump Shocks'... With their 5 inches of movement, they will coast over 4 inch Speed Bumps, without you ever feeling a thing... Just 400 Dollars from your local supplier...
  3. scifi

    Securing studs into rebuilt cylinder -advice?

    If your studs have a coarse and fine pitch, the fine pitch nut end should undo before the coarse pitch. On old British engine studs, the coarse pitch was BSW and the fine was BSF, mostly used in cast iron parts without lubrication or Loc-tite. .
  4. scifi

    Bashed up but better

    I am sorry to hear about your injuries, hope they get better with time. As trials require full lock to lock movements with the handlebars, will this be Ok with your restricted arm movement..? On a road bike you only need to move the bars an inch or so in fast bends, but trials requires the full lock quite often. There are a few venues (e.g. in N Wales.) where the course in-between sections can also be a challenge, think of slippery muddy 100 yard climbs etc. Will you be Ok if you need to get off and push..? Also most courses are 4 laps of 10 sections nowadays. Ask locally if there are any simple events to attend.. I hope it works out for you.. .
  5. scifi

    No Snap!

    Just noticed something else that will prevent a wheelie... You ought to try 2nd or 3rd gear, not 1st. The camera's wide angle view makes it look as if you are going faster than you really are. I can generally get my 175 up to my ears, and straight back down in less than 8 feet, in 2nd gear. .
  6. scifi

    What Is A Twinshock ?

    I suppose you do realise that it is possible to buy a brand new 36a Villiers engine, and fit it into a square section frame that you have recently built, and call it a classic bike. I have yet to see any vintage Scott, Rover or Sunbeam motor cycles, but maybe I just go to all the wrong meetings. .
  7. scifi

    What Is A Twinshock ?

    Quote... Rule of thumb :- any modifications I make are ok, anything that goes one step further is cheating. Showing my age a bit, but I remember a time when if you raised the ground-clearance, it was frowned upon. It should be worth stating in the rules that a seat of 1 inch or more thickness is required... But who needs more rules... .
  8. scifi

    No Snap!

    Yes it is number 4, but it is a very odd size, not often found in O Ring Kits. ( from memory maybe 4 x 1.5..?) To tell if the O ring is worn, it should be a squeeze to put the float bowl on. If the float bowl just drops off the o ring, then it is too slack. You can use a smear of silicon grease to lubricate the fit. .
  9. scifi

    No Snap!

    Have you checked the ignition timing...? If it is retarded, then the response could be slow. Also if the points gap is on the small side, it will retard the ignition. The TY175 has Contact Breaker gap = 0.35 mm (0.014 in.) and Piston BTDC 1.80mm (0.070 in.) I suspect the 250 is similar.
  10. scifi

    Live spark plug lead

    I think the current is much less than 0.5A , cos if you work out the power ( VxI=W.) you would get 50,000 x 0.5 = 25 kilowatts... Nothing on the bike, including the engine produces that amount of power. I think the current will be much smaller, maybe micro amps, or milli amps at the most. There were 5, 000 ohm resistors that you could insert into the plug leads, which would reduce radio interference, yet do very little in reducing the voltage. Your plug lead needs a much higher insulation to avoid the current leaking to ground, or to your fingers.
  11. scifi

    C15 fork stantions

    Why do you want longer Stantions and Springs, are you thinking it will give you more travel...? ( cos it won't.) The travel distance is set in the slider, being the distance between the bump-stop and the upper bearings. Maybe you just want to convert your bike to an Easy Rider type Chopper..?
  12. scifi

    Front brake wont lock on 2018 Sherco factory 300

    You need tyres with less grip, have you tried Mitas..?
  13. scifi

    OSSA MAR 4 speed?

    Looks like it will do the job, as long as you don't want to win any International Competitions. My MAR has a similar paint scheme, but does have 5 gears. I find the crankcase is quite wide, so for some rocky trials I ride my Yam TY175.
  14. scifi

    74 ty 250 wont rev out

    Sound like it is running too rich at full throttle. You haven't done something daft like clean the main jet out with a twist drill have you? Or perhaps you have put the needle back in the wrong notch. Either way you should have a sooty plug, to confirm it is running rich. Maybe the cure is to reduce the main jet size until it gives the correct performance. edit.... Just had another thought... Is the Cold-Start mechanism working correctly, with no rotting of the rubber seals.?
  15. scifi

    Trial bike for single trail riding

    Hi Lefebvre, your idea about the seat/fuel tank is good if you intend to ride for many miles at a time. Most Trials riders change their rear tyre before it wears more than 2mm, but for Trail riding you can ride them down to 1/4 tread depth and still have lots of grip on forest roads. Also the tyre pressures should go up from 6+4 F+R, to 12 all round for road work. You may find that the trials gearing is quite low for fast road work, so you could try a larger gearbox sprocket, up from 12t to 15t would get you moving a bit quicker. Have fun...