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500cc slider

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  1. 500cc slider

    Yamaha 1982 IT 175 head tension

    Hi, Can any one tell me the head tension for a Yamaha IT175 please? Thanks heaps.
  2. 500cc slider

    Valve spring cups and seats.

    Hi, Im working up an old 1984 xr100r for flat track, I have flowed the carbs, manifold and ports, got a fat cam and heavy valve springs. Unfortunately i didn't get the bottom spring retainers or the caps which hold the collets. Can i make these from aluminum or would that be too soft? I have some xr100 ones that seem to be aluminum from BBR but im unsure. I am a fitter machinist so if i get the correct material i will make them. Many thanks for reading and i look forward to reply's. PS any fast tips appreciated, like a tuned exhaust pipe dia and length maybe?
  3. 500cc slider

    250cc 4 stroke

    What bike, up to 250cc in 4 strokes puts out the most horse power? So far i have the 2012 crf 230 at 17 hp 2012 crf250x at 32hp 1985 xr250r at 30 hp Thanks
  4. Hi I have an old Yamaha xs250 that im getting out of the shed. The front brake sticks on. If i squeeze the lever the caliper grips but wont release. To release it i open the bleed nipple. Would the problem be in the master cylinder or the brake caliper? Thanks lots. PS sorry its not vintage, only classic.
  5. 500cc slider

    xr 250 1984 1985 cylinder head

    I have 2 xr 250's, one is a 84 the other a 85. They are in good condition but they have the common cracked heads. Its heaps hard to get them fixed and prices are more than a new one. Honda say that 85 and prior heads are not available but the 86 model is available. My question is will it fit? Or Is there a better alternative for high performance? These are to be flat track bikes in Aust. Thanks heaps Matt.
  6. I bought a 2valve jawa in a sand racer mark 2 frame, the frames were made from 68 onwards i think but that's not to say its the original frame for the motor. The two valve jawa were made up to 75 i think, mine has got a real low engine number so im thinking it may be pre 70. Its hard to track as jawa changed so many times. The engine number is 5458 Any help apreciated.
  7. These two engines look similar with the rfvc set up but i see gasket kits and parts differ in the dates, some say up to 84 and others 85 onwards. Whats the difference? I have both motors for rebuild. Doing the 85 model now. Also any tips on tuning or setting the carbs, leads to hot performance parts, exhausts any thing accessory for them would be great. Thanks Matt.
  8. 500cc slider

    Helmet hair

    Hi It is much safer to have your hair tucked in. In a big step off you may get the lot torn out and also the dirt and the heat is harsh. Mine is long too but i just tie it off low and tuck it in my jacket. It would be so horrible to cut it off, long hair always looks great.
  9. A while ago now he wanted to sell his bike, XR350. He spend days polishing and buffing and touching up. Fitted new grips and mirror, the bike looked like new. He got on it early on the Saturday to take it out to sell, he got to the first corner and stepped off, the bike slid on its side busting the new mirror, tearing the hand grip and gravel rash'ing the rest. The moral is..... Dont tyre shine the tread of the tyres! It is silicone and you will go ass up. He was rather angry believe me, i didnt say a word..
  10. Thanks, i got 42mm divider setting through template transfer (on paper first ) i should have marked it out before i bored the center hole
  11. i was thinking pi x d = circumference / 5 = so 3.1459 x 72 / 5 = 45.2389 But after trying it i was wrong, i think its got to do with straight lines and curves. Cheers. and im only using a drill press, so i need to scribe them, centre punch and drill.
  12. I have to mark out 5 holes equally spaced on a 72mm dia, whats the formula again ? I know its 72 deg but i haven't got a dividing head, ,i have compass,dividers and vernier caliper etc. thanks Matt ps Like on a car wheel stud pattern, 5 studs. pcd=72mm
  13. That is invaluable info, thanks heaps.
  14. I need a xr250rf RFVC bare or complete head, it is the twin carby and twin exhaust model of 1985. Its driving me mad trying to find one. Honda want my left n#t for one (very expensive $$$) Thanks heaps Matt.
  15. I have just got my son an old 1985 xr 250. These bikes has been known to punch out big h/p with twin carbs and exhaust. RFVC (30hp std). I know the less exhaust pipe curves the better and where it does curve try and make them long and flowing. In order to obtain maximum results matching the carbs, cam and capacity how would i work out my pipe size and length? Thanks Matt. PS We got 14hp out of a 7hp xr 100 so i hope for at least 45 from the 250. Giddee up