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jc2

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About jc2

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    Advanced Member

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  • Bike
    KT, TY175, Bultacos

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  • Location
    Toowoomba, Queensland
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    Male

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  1. jc2

    Zundapp Trials.

    Here's a few more
  2. jc2

    Zundapp Trials.

    I have a keen interest in these too - in fact anything from the euro manufacturers that got little/no coverage in the UK press back in the day. Some fascinating machines Here's some pics to get you going: Franke again Sengfelder's bike Said to be Jacky Ickx's 1964 works 125 The other side of one above Another nice one And a Rickman Zundapp trials
  3. jc2

    Gaunt Suzuki

    Please do post some pics cheers
  4. jc2

    what bultaco engine used in this racer

    I could never understand why Bultaco didn't use/develop that engine more in their motocrossers, especially the big-bores, but I'm told it is a very heavy engine and that Pomeroy hated it. Apparently that meant end of story at the factory at the time, whereas the Brits (Malcolm Davis & Vic Allen) loved the last 400 prototype based on that engine. Seemed to me to be a much better design than the chain-drive engine. Anyone know the truth?
  5. jc2

    325 Cylinder head on 250 Model 49?

    Some dealers back in the day took 125/175/250 Bultacos out to 325 using a new liner but it was a hec of a lot of work - press out the old liner, bore cylinder to take new 325 liner, open up the transfer ducts, split the cases to enlarge the crankcase 'mouth' for the new liner, machine head & combustion chamber adjusting dia & C.R. to suit larger capacity, then fit bushes on the 16mm gudgeon pin (of the smaller engines) to take the 325 piston (which used 20mm pin). Bert Flood sold the kits in Australia & a local rider had it done on his Sherpa S 125 by our local dealer. But it always seemed a somewhat less than satisfactory practice to me, especially bushing the 16mm pin to take the 83mm piston. And if you didn't get the transfer ducts and head mods right.... These days guys seem to prefer boring out the 250 to take 76mm GasGas piston, giving extra 28cc. Don't know if they just bore the std liner or make new one. The Bul 250 liners are 4mm thick so that would only leave a 2mm thick liner if they just bored the liner. For me that'd be right on the limit. Don't know if the deck ht is correct or if you need to run a reedvalve with the GG piston either (ie if there's holes in the skirt.) Another idea I've toyed with but never fully investigated is to use a 75mm KawJS550 watercraft piston, up to 1990 model which were pistonport engines (later models were reedvalve). Wiseco list them as having 16mm gudgeon, same as 250 Bul, but don't know if deck ht or ring locating pins are suitable. That'd give 21cc extra & more meat in the liner
  6. jc2

    no cut. change the head angle for TLR200/250

    For some reason that first website transposes "steep" to "spam", so whenever you see "spam", read it as "steep" or "steeper" to make proper sens of it.
  7. jc2

    V Force reed valve for TY250

    Thanks for the info Tony. I'll be interested to hear how engine performance compares to one with standard Yam reeds
  8. jc2

    M27 exhaust front pipe

    I checked my M26 Matador engine and pipe. The pipe does clear the head with no cut fins
  9. jc2

    M27 exhaust front pipe

    Try the Matador Mk3 (M26) and/or Mk4 (M75 - not the M82 SD model)) pipe. You may find it fits the M27 engine. (I'll look at mine tomorrow if I remember)
  10. jc2

    Hello fellow Montesa owners!

    Very good advice about the position of the kickstarter. I can't remember now whether it's the 1 o'clock or 2 o'clock position for the kickstarter they say not to exceed. From memory its at the bottom of the stroke where the stop tab punctures the case if you have it too far forward. Nice bike by they way.
  11. jc2

    Bultaco Alpina design changes

    Yeh, I wondered something like that too. For what it's worth, I've had a go at summarizing the changes that I've gleaned over the years: Alpina changes M85 – near identical to M80 Sherpa, but with Matador gear ratios, longer seat & larger tank. One-piece tank/seat unit. Airbox under seat a la Sherpa. Full width 125mm dia front hub , mud-catcher alloy rims, round barrel & head, bolt-on footpegs, 2-piece header & midbox, triangular rear muffler. Single gusset at steering head (on centreline of tubes). Tapered fork-tubes (at top triple clamp). Alloy top triple, steel bottom, with built-in angular offset (a la Sherpa). Some had high-mounted front guard (early?), some low-mounted (late?). Late ones had recessed swingarm pivot (like early M91/2 Sherpa) & weld-on footpegs & the swingarm was slightly diff to match the recessed pivot. Not sure if they used the longer Pursang footpegs or shorter Sherpa pegs. M99 – 325 version with square barrel & head, 60mm stroke. M115/116 – extra frame tubes above swingarm pivot (like late M91/92 Sherpa). Frame seemed lighter, perhaps thinner gauge but still mild steel. Top shock mount moved rear-ward (on bracket behind the rear frame tube). New tank-seat unit. Airbox on right side (somewhat like M107 SD Matador) under removable cover. Angled/offset inlet manifold. Conical 140mm front brake, chrome-lined. Stepped gusset at swingarm pivot a la late M91/2 Sherpa. Pursang alloy triples & non-tapered fork-tubes to suit. No angular offset in triples (which is why these & later Alpina’s steer so differently to Sherpa’s) with 20mm less overall offset. Shorter wheelbase. Shoulder-less alloy rims. Dual gusset (folded over) at steering head. New longer seat; slightly new colour scheme. On these models the rear central-downtube was recessed for the swingarm pivot (like the equivalent model Sherpa) which I believe enabled the engine to be mounted about 15mm further back. I’m lead to believe the fork-tubes are longer than Sherpa ones too but not sure when this occurred. 350 engine had 64mm stroke, bigger crank (wider and larger dia), different crankcases to suit & diff stud spacing from earlier 325 engine (if I recall correctly). M137/138 – much lighter Cro-mo frame, said to be 8 lbs lighter; very thin gauge which fractured everywhere, despite extra gussets/tubes under the airbox. Left side shifter, right side brake, Mk8 pursing rear hub (chrome-lined), one-piece header/mid-box, boomerang/clubfoot rear silencer, sidestand attached to swingarm (instead of frame), new swingarm (20mm longer?) with what appears to be lugs for passenger pegs. Longer wheelbase, more ground clearance. New clutch cover. My 137 engine has square barrel & head & duplex primary drive. Later models (165/6, 187/8 & 212/3) had completely different frames, swingarms, tanks, shocks etc to the earlier Alpina’s, with rear engine mount bracket hung from swingarm pivot. These are similar frames to the 158/9 Sherpa’s and very different bikes to the early Alpina’s. Forks, triples & wheels look to be about the only things in common with earlier Alpina’s. They were said to have gone back closer to the Sherpa, but maintained the Pursang triples & Matador/Frontera gear ratios. M165 & 187 250 models appear to have the shorter 158 style Sherpa frame, with wheelbase specified as 50”, whereas 166, 188, & 212/213 models have the longer 159 style frame, with wheelbase specified as 51.6”. Bultaco brains trust, feel free to correct it where required
  12. jc2

    MZ Forks Progressive springs

    You may find progressive springs for the 34mm TY250 forks may fit and improve things
  13. jc2

    Bultaco Model 10

    According to one of the Sherpa books I have, apart from the tank, it also got alloy (mud-catcher) rims, a longer bash-plate, steering stops, larger reinforcement gusset at the steering head, & relocation of the VIN to the right side of the steering head (from left side above the swingarm pivot). It doesn't indicate when, and I don't know how accurate the info is.
  14. jc2

    Sprite trials bike age?

    Its only a minor difference so you'd think yours would be legitimately P65 eligible.
  15. jc2

    Sprite trials bike age?

    Nice bike Click on this link: http://s1085.photobucket.com/user/trialrider/library/?sort=3&page=1 Is that your model? Except for the rear loop it looks like it to me. The copy of the dated magazine ad shown there (from when they were available back in the day) is Nov 18 1964 . Does that make yours a '64 model??
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