TY250A original gearing question.

[scot taco]

Hi Johnny,

That plug looks a bit too lean to me,but I am definitely no expert and I,m sure others will chime in.What are you mixing the oil at?

Congrats on scoring such a clean TY.That is a really nice one!

 

[johnnyjazz]

hello scot taco..thanks so much for the reply, currently going 40:1 on the premix....

maybe do i need to turn the air jet in a 1/4 turn? i had set it to 1 1/2 out like the manual said but i noticed it has a #112 jet and i see the manual says it should have a #114.  i've been trying to learn about jetting and what its all about    maybe they put a #112 as it gets a bit chilly here in winter?

no doubt whoever owned the bike originally (apparently a farmer in Pennsylvania) had been into trials enough to swap it to a 12 tooth on the front and disconnect the oil pump and look after it!

[tony27]

Get the #114 main jet if possible, in theory colder temps should require larger jets as the air is denser. The smaller main jet may have been fitted when used in competition as the throttle is not open for long especially when compared to using on the road

Biggest problem you may have is finding parts for the TK carb as they aren't very common, the later models with Mikuni carbs are easier to get parts for as the jets are the still the same in new bikes

[thats_a_five]

That plug looks pretty good, maybe a tad lean as mentioned by Scot_Taco.  The carb has 2 screws.  One is idle speed, other is idle mixture.   Idle speed screw is central to the slide bore, mixture screw is offset and usually smaller head size.  Adjusting the mixture screw out and it will richen the mixture but mostly at idle - minor effect at higher speeds.  Other ways to richen the mixture are to adjust the little needle in the slide up (put the clip one groove lower - beware those little 'C" clips are tiny and always try to fly off into the nether regions of your shop).  It is counter-intuitive but reducing the oil percent will richen the mixture but I wouldn't go less that 50:1.

 

Regarding upgrades versus original, I have to ask about how aggressively you ride.  Reason is, many of those original parts (Tank, headlight rim and bucket, switches) which look really pristine on your bike are worth big money as spares.  Ride aggressively you are likely to drop the bike, damaging those and reducing their value significantly.  So you might want to consider looking around for some used parts or upgrades, so you can take the pretty parts off and keep them pristine.  If the shocks are OEM, they might be sacked out and upgrades might be worth it. 

 

You might want to take a look at Bob Ginder's site B&J Racing.  He has some cool info and stuff for TY's. 

 

Enjoy!

[johnnyjazz]

thanks so much for the reply again my friend.

at best i ride more traily/green lane and clubman trials level than anything else.

ive ordered a set of falcons for the back at  'feetup funs' suggestion in another post.

ive removed the oil pump and put a blanking plate and now have all new cables too.

this bike is kicking my a*** in some ways though (but a great learning curve!)....

i need to replace the fork seals and maybe get new springs though im not looking forward to working at that damper rod bolt! hopefully the good lord will assist.  i have a rattle gun so i should be ok i hope?  ive been watching vids on youtube so feel fairly confident.

more importantly though....arrrggghh ive noticed the tank is leaking.  its only a tiny bit but im guessing its a seam? what to do?...kinda pin hole vibe leak. the paint is so nice on the tank and i really think its all original...hmmmmm...man vs machine.  machine winning thus far.

is that stuff kreem any good? JB weld...Bondo tank fix?  or send it out somewhere?... sorry to ask so many questions my exalted shamans of mechanical expertise! any advice, recommendations or guidance gratefully received.

as always, with very best wishes and bright moments from brooklyn. johnny

[feetupfun]

First work out exactly where the leak is. If you are lucky it will be underneath the rear end where many of the A model tanks develop a crack. That way it can be welded without damaging the paint job. No don't line a steel tank with kreem.

If it is a fatigue crack then a repair with anything rigid like JB weld is unlikely to work for long. If you have some repair compound that can do a flexible repair on the outside then you might get away with it.

Before you buy new springs, change the fork seals and set the oil level to 125mm from the top of the tubes, forks fully compressed with springs out. Use 5 or 10wt fork oil. Using the air space in the forks as a spring by running the oil level at that height will provide better bottoming resistance. When you have the springs out, measure their lengths and post it up here for advice on if you should add anything to the length of the preload spacers to set the sag to a good number.

[johnnyjazz]

Thank you again so much 'feet up fun' for your wisdom and kindness of sharing it.

i see in the manual the fork springs should measure 400.5mm.  i am hoping to get to it tomorrow so will report back my findings.

i hope very much too that the leak is on the underside at the bottom.  if that is the case, i see the procedure for welding it is fairly straight forward in the hands of the right person.  again i'll report back my findings.

still love your quote. always timely.  hamlet yeah? talking about Denmark i always loved the one from that play 'There are more things in heaven and earth, Horatio than are dreamt of in your philosophy'

thanks again guys! great advice.

 

[johnnyjazz]

OK, salutations once again friends,

so i disassembled the top bit of the forks..tho .cor blimey.gov! that cap nut was a bit of an ordeal. got there in the end

my fork springs each measured exactly around the 400mm mark and after changing the oil (from half a cup of sludgey grime) to 125cc of nice fork oil, there was a huge improvement. i did notice i am missing the the packing # 434-23163-00.  is that something that i should definitely have? fork seals are still leaking too so that's the next job.  however, i noticed today when i pulled down the top left gaiter the chrome seems a bit damaged.  is it high enough up it doesn't matter or do i need to have the leg re chromed so i don't damage the new seal?

lastly, traced the gas leak to what i think is the seam on the underside on the right.  that said, it only seems to leak with a full tank of gas.  i drained half of the tank and so far it hasn't leaked.   im thinking of my options.... does somewhere like this look any good to you experts? does it look rubbish inside the tank or ok you think? http://www.motorcyclefueltankservices.com/about.html

i enclose a few pics for your advice and guidance.  humbly yours and wishing for you all a great weekend!, johnny jazz

Edited September 15, 2017 by johnnyjazz
mistake

[feetupfun]

When you change the fork seals, put in at least 175ml of oil per leg. My previous post mentioning 125 millimetres is a distance measurement, not millilitres (volume). Sorry for the confusion.

I see the pits in the tube chrome and will post again here when I've checked if your pits are high enough not to worry about.

It looks like your fuel tank has previously been quite rusty inside and someone has treated it chemically to remove the rust. It is possible that your leak is a tiny rust hole somewhere in the tunnel above the seam weld and may be very hard to see. This would explain why it only leaks when the tank is near full.

Another thing that may help is maybe you aren't loosening the top tube clamps when you remove the fork caps. These clamps need to be loosened whenever you take the caps off or put them on. The clamping action causes the fork tube to reduce slightly in diameter which can cause the cap threads to jam.

[feetupfun]

If you have standard TY250 fork tubes and they are positioned with the top ends of the tubes flush with the top edge of the top triple clamp, the fork seal will get to 57mm from the underside of the lower triple clamp on full compression.

I've put a black pen mark at 57mm in the photo

[johnnyjazz]

Thank you so much my friend! i am truly in your debt for your kindness in helping us newbies learn this stuff.  thank you so much for passing it on

im hoping my stanchion is ok and below the 57mm mark...it looks close though.  though i should think for a beginner like myself it is less imperative to get it fixed as it probably wont be facing the vicissitudes that a pro like yourself would put it through?

anyways, it was a lovely afternoon in Brooklyn and i found these two spots today where no one seemed to mind me playing around.

i revisited my 70s classic Don Smith 'how to ride trials' book, and was just working on going as slow as possible in 8s and trying to bunny hop a brick.

i cant wait for my new falcons to come! thanks you for your recommending those too sir.

so much to learn about trials skills and mechanical skills...so onward and upwards!

wishing for you all a great weekend of riding and thank you for making me feel welcome in your forum...

 

[b40rt]

You'll probably find it harder to bunny hop with new shock, the lack of damping in knackered ones gives good lift !

[badmotofo]

Urban trials – that's great! I wish I had just some little piece of something to go and put around. No such luck in the SF/Bay Area.

[johnnyjazz]

Dear super trials friends, what are your expert thoughts on 'Caswell' tank sealer? after trying to do some research it appears its the best option there is for the pin hole seam leaks i have. is it a good choice for a steel tank.  i read mr. feetupfuns advice that it's not good if you bend/ding the tank- although it was used to good affect on fiberglass tanks.

i guess either that or maybe i need to get a new tank.  i see clarke racing make one that will fit.   is that a better idea at this stage- and retire this one as a shelf trophy?

id rather pay $40 for sealer than $240 for a new tank but want to do the right thing in the long run

(and also @ feetupfun those dings in the forks were at 50mm so happy days!)

many thanks always for any revered guidance and encouragement...

[feetupfun]

If you are never going to dent a steel tank, then a stiff tank sealer that is compatible with modern pump fuel (epoxy resin) is OK. If you do dent a metal tank that has a stiff tank sealer, the lining will probably crack away from the steel and you won't be able to get the dent pulled out with heat and you won't be able to reseal it with epoxy again. So for a bike used on the road an epoxy lining is probably a suitable cheap fix. If the hole is in the tunnel it should be able to be welded or soldered up without the repair being visible when the tank is on the bike and won't damage the paint on the pretty parts of the tank.

If you use a flexible tank sealer in a steel tank, it will eventually swell, go floppy, come loose and cause you lots of dramas while you try and get the liner out through the filler hole. I have had to do this in a TY80 (steel) tank and it took hours. The tank didn't leak, so it looks like someone had lined the tank just because it looked a bit rusty inside.

You can find metal tank leaks by slightly pressurising the tank (lung pressure is usually enough) and brushing soapy water on while looking for bubbles. Using work shop air pressure or tyre filling air pressure can cause the tank to go way out of shape (permanently).