johnnyjazz

mellow as a cello now thanks!.

i have the 250a manual and parts list as a pdf if youd like? pm me. more than happy to share and put something back. Ive learned so much from the awesome mechanical wizards and trials masters here!!

hola,- just my two penneth fwiw- but i found a complete original seat assembly, pan, and hardware for the TY250A in fantastic condition on the bay recently for $175 so don't give up hope! it originally had the long trail seat so i was keen to find the original as its a few inches lower and narrower. hope you find what you need!

Thanks guys, really appreciate the input! i'll just leave em..i did the oil/seals a while ago and if you think the springs look fine and the shorter length is ok then that's all i needed to hear! i know a lot of this knowledge comes from experience so thanks again for sharing thoughts totally take your point about new techniques on old bikes but having just watched these two vids really made me rethink my game!

hello wonderful trials forum! so...another question from the newbie in brooklyn...thanks for all your help and patience so far ive been trying to practice front wheel hops and really having to work hard at it. now, im aware my technique is ***** and even trying to do these 'modern' things on an old twinshock requires a lot more effort and diligence than on a mono shock, but i pulled my fork springs again and measured them against the 400.5mm i have in my manual and they came up a wee bit short.. would this little difference have a big effect on the rebounding of the spring? i see i can get a new pair from b and j for $90 so happy to take a hit if need be? few pics showing lengths...the silver lines are at exactly 400.5mm... can any of you experts tell me if i should just get some new ones or i just need to leave em and work harder at technique? thanks always so much!

im no expert by any means...but ive had the bike about a year. here is what i have from the manual with regards your oil question, but im sure there are a myriad of options that are available since 1974.....oil has come a long way! cant remember exactly what i used...probably something cheap and cheerful i 'borrowed' from work...

Hola, i thought i would chip in with my two penneth as i was asking exactly the same questions here recently.... I live in brooklyn NYC (hardly a trials mecca!) and last year an original gorgeous ty250a found me that had been stored indoors for 30yrs. i took it on as a project instead of having a mid life crisis It originally had 12/53 gearing and i found this a bit too slow to keep up with 40-50mph traffic in the city. Perfect for trials though with tons of low torque and great for practicing wheelies and super slow speed stuff in a few secret spots i know (construction sites). having been struggling with highway speeds, at feetupfun's suggestion i switched to 16/53 and the bike is much happier pottering around at 45mph and the engine isnt working too hard. However, it's a double edged sword as i lost all the ability to practice my trials! its way too fast gearing to even think about having the bike move at walking speed without slipping the clutch. and its much harder (for me) to get the front wheel up...fyi, the original gearing on the bike was 14/53 and the subsequent models (b/c/d/e) all had 13/53. but feetup's recommendation (and he is a giant of knowledge and experience) of 12/53 is where you need to be for trials. as an aside...i dont think a ty250a is really all that stable above 50mph? i went on the highway last week and at 55mph got pretty nervous as the bike seemed to be doing wierd gyroscopic things as the road surface changed...not fun and pretty dangerous. maybe there's something wrong with my bike as i have read on this forum a ty250a can go 80mph but i find that hard to believe from my experience mucking around with gearing but who knows!?... also, i read that someone rode coast to coast US on a ty250a... so i guess anythings possible! anyway, hope that helps...best vibes from a sweltering NYC! johnny

Thanks so much Feet up fun! you are the best as always. Macy's here i come! your kindness to share is always legendary. very best wishes from NY! johnny

Thanks so much Section Swept! really appreciate your input yeah, i took all the auto lube system off and blanked it properly etc interesting for road use you recon 60.1? i know its a trials bike and not built for road use....but it kinda found me so we just coming to a compromise what with being in the city. obviously brooklyn NY not best place to find many trials spots! i had a few i used to use but the cops not so keen. everything is suddenly 'private land'... so trying to make it more a green laner.. but yeah, i hear ya...brakes suck, geometry sucks...just re living my youth and trying to save a piece of history... re the two position air screw you mentioned, the guys on here told me previously that the choke can be used in that way. they would put it on during long road sections and ride through the 'burbles'...had the effect of cooling the engine i learnt. and re the seat gap...i agree, it def seems like it wants to go an inch or two forward but on all the original photos i've seen they all seem to have that gap. i enclose a pic here..unless im mistaken this is how they came? and your bike looks beautiful sir, magnificent work!

Hello dear friends, Johnny here in NYC hoping to get some advice from some of you super knowledgeable folk few things if i may.... 1, When i got the bike it had the long trail seat. i recently scored a really nice original seat and pan which i'm super happy about. however, i didn't realize there was such a big gap between the seat and the tank. i think having the old trail seat sit flush with the tank has maybe discolored/chipped it. Q/ what would be the easiest way for a novice to clean that bit up so it looks a little more aesthetically pleasing or would i need to really re do the whole tank? maybe there is a generic yamaha touch up white? ive attached some pics so you can see what i'm talking about. 2, I am replacing the the top cylinder fins as the original has a cracked/broken fin. Q/ other than a new copper gasket is there anything i should know or look out for. Is it pretty straightforward and i'm presuming it's ok to swap them between bikes? 3, Having set my bike up for more road gearing (at feetup funs suggestion 16/53) i can comfortably sit around 45mph now. I use a pre mixed 50.1 synthetic husqvarna high octane ethanol free fuel (i can get it at work) and the original B7ES plug. Q/ For more of a road riding application should i be using 40.1 and a B8ES? or am i ok where i am...im terrified of blowing the engine up but also dont want to gunk it up with unnecessary oil....i know pre- mix ratios are highly controversial but i just don't feel i know enough myself to make an informed decision. 4, and lastly...Q/ correct/optimum tire pressures for street use? any insights into any of these questions would be gratefully received. Thanks so much for all your help. i learn so much here at trials university. many thanks in advance and bright moments!

Thanks scifi,- when i got the bike the air box hose and lid were in a box of parts, so im assuming someone had taken it off at some point! i've hooked it all back up with a nice new universal filter and 'no toil filter oil' and at feetupfuns suggestion i will refresh the tired TK with a nice new OKO hope the engine didn't got too damaged from the chrome slide chips! Thank you all for being such an amazing forum of knowledge and kindness to share it! best wishes from brooklyn...

Thank you so much as always for such knowledgeable help! New OKO carb it is! i'll put the TK in the box along with all the other stuff ive been replacing on the bike

Hello again friends and greetings from NY. Hope you are all well! sorry to be such a noob...but i was hoping if someone with more expertise and experience would tell me if my slide is worn past the point of no return and needs to be replaced? bike seems to run ok but trying to give it as much TLC as possible while its in my custody! i recall 'feetupfun' saying the TK carby was really awesome and when working as intended is hard to beat, though if the the slide is worn it can run rich. however, im looking at $50 on eebs for a new slide but can get a whole new OKO carb from mid atlantic trials for $100 so not sure which my best option would be.. any ideas/opinions? and also, in my parts manual it says my slide is a #3 but the only one i can find online is a #2.5. would this matter much? many thanks always, johnny

ah! yes of course thanks tony...choke = more fuel not air. my bad. and does that mean if the manual says a #114 main jet when the bike ran the oil pump from new then premix would require like what a 116 or 118 jet or something? this is all new to me jetting and stuff... but exciting. thanks so much for your help and input

wowsers guys, you are all the best! coming here is like going to school for me so thank you senor feetupfun, thank you always for such valuable chunks of knowledge and experience. i totally understand now how the choke would help cool the engine by letting in more air. however, after much trial and error, at your recommendation i stuck with the original 12/53 gearing and just working on super slow stuff. trials all the way! i have the carby set to all the correct specs as are in my manual, 114 main, clip position 4 etc. she's running a beaut now after replacing that o-ring, i feel so lucky and pleased to have her in my care for a while. Trials is so great and just as in music, the slowest stuff is the hardest and most challenging. im utterly rubbish mind you, but getting better in the empty parking lots and industrial estates around Brooklyn! the cops haven't been best pleased at times, but having it all street legal w/ insurance etc really helps. but wow, good to know potentially with right jetting and gearing a ty250 motor could do 80mph and one question, hypothetically, if i were to be riding on a highway at 60mph what size main jet would i need? bigger yeah to let more fuel through? and presumably at higher speeds 40/1 is a much better choice than 50/1 pre mix? not that i'd run her like that, but great to know just in case... really inspired to be learning so much about something new. thanks again to all. best wishes, johnny

sorry to revive an old thread...hope thats ok! but 80 mph!! really?? you kiddin?....im lucky to get 40-45 out of mine, tops!!! (w/14-53) though interesting you talk of the choke as an 'enrichment valve'. does that really work like a booster switch or something at high speeds? i'm curious also when you say you could never overheat the ty250a motor...can you rev the absolute beejezus out of the thing? im just worried about blowing the engine in case i got the pre mix wrong!...(.im at about 45.1....) thanks for any advice, johnny

Thank you Section swept! great advice

Thanks again feetup fun for all the help. The O ring i meant is not the air screw but rather for the screw that holds the needle jet/main nozzle in place. i believe this being worn (as it is) can cause running rich, but im pleased to know to diagnose wear on the needle and needle jet too. Can't find any new needles on eebs with part #434-14336-00 for the TK, are there any other ones that fit? that said, it seems by the time i replace any TK parts it might be more efficacious to get a new carb altogether? if that's the case would i go for a mikuni 26mm yeah? or is the oko carb from mid atlantic trials any good? thoughts and opinions as always, gratefully received.

hi scifi, i got the metric (mm) set but they are all skinny. i need one like a dougnut. i think ive found some on eebs for a few $ so i'll take a gamble...but i realised i gotta change it as im running rich and im pretty certain its that! (again thanks to this awesome forum) btw, totally noob question so please excuse my ignorance...but in my manual it says the clip on the needle needs to be in position 4. Does one measure from the top so the clip is one notch from the bottom or vice versa with it being one notch from the top? many thanks always

Pm sent great links too, thanks!

Thanks again friends! methinks i have enough on my plate with my TY project anyway (and keeping the wife appeased) The ad never stated the model so i was just guessing it was a 247 from my (very) limited knowledge of montys, but as always i learn so much here! he did say it was original though...if anyone else is interested i can post the ad? best wishes from brooklyn

sorry, slightly off topic from original post, but could anyone tell me the size or generic part# of the o-ring i need for the needle jet set screw in the TK carb bowl. i got an 'automotive o-ring set' but none fit properly and the part# on my yamaha list brings up nothing on ebay. many thanks!

Thank you so much!! this forum is just the best for guidance and knowledge. really appreciated and costly mistake avoided!

Hello Friends, new to Montesa forum. Guy selling this locally, says its all original. seems like a pretty good price? (compared to what i paid for my minty TY) any advice or guidance gratefully received! are these bikes easy for parts/spares, anything i should look for specific to these bikes if i go to see it? wife certainly not happy at the thought of another bike but trying to convince her it could be an investment?. many thanks always, johnny

Thank you so much Brewtus! great advice and really appreciated. fingers crossed the crank is tight, though if i have the left side off (and have the parts already), i'm guessing i might as well do the points, condenser and coil too? i just want to try and make it nice