pbear62

Hi Kevin, Re: your item #5 above: I have a 1984 TY250S (red frame/steel tank model) which I have just finished a resto on & I also read the CMM article by Stan Stevens. My TY was particularly bad in regards to the rattling & clanging these bikes did in the day so I was keen to see what difference these mods would make. I only did some of his porting mods though - I already had a brand new Pinky piston with the reliefs on the crown (the "bodge" he refers to) so we didn't want to modify the transfer ports straightaway (bit hard to put metal back in once it's been removed!) We did open up & straighten the exhaust port & we also machined the cylinder head as per the magazine article. We also cut open the exhaust system & removed 33 years worth of accumulated oily sludgey packing & replaced it with new stainless packing & made a new "straight through" aluminium tail muffler (similar to the DEP/WES type) We fitted a new air filter element but didn't cut the airbox lid up or change the jetting which still feels fine. We also left the steel ring on the flywheel. The bike still has a bit of a jerkyness on the over-run & because of this, it still wants to run on after blipping over logs etc but the power is much stronger & smoother in 2nd & 3rd gear situations. I hope this is helpful for you, Cheers, Andy

I did mine the same way as Searay175 did - doing it this way makes the cuts & rewelding less visible when fitted on the bike. Takes a while to dig all the crap out but definitely worth doing!

Excellent job Mike - I particularly like the yellow one. Too nice to get dirty now though! Cheers, Andy

Thanks for the info guys - will have a look on TY Trials & then possibly get some number drills too. Andy

Hi guys, I'm just getting my TY250S (#53Y model) head machined (faced & squish band modified) & am getting the barrel rebored to suit a new Pinky piston & have been advised that it's going to need a bit of an increase in jet sizes when I get it all back together. The original TK carb (28mm) has a 110 main jet and a 48 pilot jet which is different to anything I've read about (this bike has been in our family since new & has never had jetting changed) The bike still has the original flat airbox lid with the 'snorkel' fitted which I believe will also need modifying so it can breathe better. Has anyone got any suggestions for a starting point with the re-jetting? Yamaha don't have many different jets available & they're expensive too so I don't want to have to buy too many! Alternately, are Mikuni jets the same size & interchangable with TK jets? Or, should I just replace the whole thing with a Mikuni? I can get a new round slide 28mm Mikuni but I've read that people seem to go for a 26mm? If I decide to go for the Mikuni option, what's the deal with the TK carby screw-on cap - it appears to be attached to the throttle cable & not removable? Thanks in advance for any assistance & suggestions, Andy

Hi there, Would your man in Chang Mai be able to make the mudguards in white to save getting them painted? I'd be interested in getting a front & rear pair made if so - do you know what they'd cost (plus cost of freight to Western Australia?) Cheers, Andy

Hi guys, Andy from Western Australia checking in ..... I started riding trials back in 1979 on a Montesa Cota 247 then progressed to a Cota 348, Italjet 350, Yamaha TY250S & finally a Yamaha TY250R Pinky. (also did some sidecar trials on Italjet & Yamaha outfits) Since 2000 I've been doing VMX & riding road bikes with just the occasional trial & practice session here & there but have never really lost the trials bug so will be getting back into competition for next season. I'm currently reviving another TY250S mono so will be scouring this site for tips, parts & info as there's nothing much for these bikes over here now. Cheers, Andy

Hi guys, I'm looking at doing a rebuild on a 1984 TY250S (serial #53Y - red frame/steel tank/fat seat model) which my father in law has had since new with a view to getting back into trials next season. Back in the '80s there were quite a few of us riding these bikes in Western Australia but they've pretty much all disappeared now. Due to a lack of aftermarket parts (& knowledge) back then we all rode them pretty much standard & just put up with the rattling & clanging noises the motors made. Before I do too much to the rest of the bike I want to see what can be done to sort out the top end of the engine & get it running better (i also had a Pinky in the early & mid '90s & it was a huge improvement over the earlier models) Since I've started looking into this I have been told of a couple of different options: #1: Simply fit a Pinky piston assy into the original barrel (I can get a new o/size Pinky piston assy) or #2: modify the porting in the barrel & skim the head & squish band. (this info comes from UK tuner Stan Stephens) With this second option there is no info given on whether the original piston is still used. (I'm guessing so as there was no mention of different pistons) Has anyone on here done either or both of these modifications? If so, which is the better way to go? I'm not aiming to get back into "A Grade" (obviously!) & don't want to get into doing any of the 270cc/shortened intake type mods either - there's no-one over here doing these mods & if I was that serious I'd just buy a late model bike! Any info you can give me would be much appreciated - I want to revive this bike but need it to be nicer to ride than they used to be! Thanks in advance, Andy