johnnyjazz Posted September 20, 2018 Report Share Posted September 20, 2018 (edited) mechanical maestros, if you could tolerate yet another question from the ignoramus..... i realized at 160lbs (72kg) i'm on the border between 40 and 50 lb springs. maybe i should have got 50 lbs as i ride mostly road here in NYC but i went with 40lbs on the new falcons as that's what the guy sent me from the UK. i know the 40lbs are perfect for trials use however now methinks maybe i need to set them on max pre load as they seem a tad soft. im used to the thread/tool adjuster and the original step adjuster type pre loads, but not sure what the procedure is for these cir-clips? no doubt its super easy and you're all laughing, but i don't want to damage them! ... just not sure how to release them and move them down... -also, if i did step up to 50lbs spring (im not getting any smaller) would going to 345mm or 350mm necessitate a change to front end or is 340mm the way to go on the TY? many thanks as always my cyber trials friends. best regards from the headquarters of overpriced living and $1 pizza! johnny Edited September 21, 2018 by johnnyjazz Quote Link to comment Share on other sites More sharing options...
feetupfun Posted September 21, 2018 Report Share Posted September 21, 2018 You can fit 50 lb Falcon springs to those shockies without modification. They are available as a spare part. 340mm shock length is fine no matter what springs you use on the shocks. So are 350mm shocks. So are 360mm shocks. If you go longer than 360mm shocks you may need to do some metalwork to let the swingarm rotate down far enough. 340mm is probably the ideal length for what you do with the bike. There are many ways to change the spring preload. One way is to take the spring off. You can then move the spring steel clip from one groove to another. This clip is held in place by the top spring retainer so by taking the spring off you can slide the retainer down to expose the clip. You will need a pointy tool to get the clip to move out of the groove. To take the spring off you take the shock off the bike, compress the spring and take out the bottom spring retainer. Another way is with the shock still on the bike. Grip the top end of the spring in one hand and pull it down away from the top spring retainer, slide the retainer down a bit and keep holding against the spring while you move the clip from one groove to another. There is a risk of pinching fingers doing it this way, but it very fast once you get good at it. It is easier doing this with two people. It's quite normal to have to use one of the lower grooves when you use 40 lb springs on Falcons on a TY250. Trials bike suspension is intended to be very soft compared with other types of dirt bike suspension so it works well in sections (low speed with the rider standing and legs forming part of the "suspension"). If you ride a TY250 that is set up to ride trials sitting down and go through a dip at speed, it will bottom out the rear suspension heavily. 1 Quote Link to comment Share on other sites More sharing options...
johnnyjazz Posted September 21, 2018 Author Report Share Posted September 21, 2018 Thank you always so much feetupfun for your insightful knowledge and kindly shared advice. Coming here is like going to school and i am humbled and grateful to have this forum and you all as my tutors! i know it takes time to reply to a question -and i've asked a lot- so again deep gratitude, deep joy and the brightest of moments to you! 1 Quote Link to comment Share on other sites More sharing options...
shakennstirred Posted September 21, 2018 Report Share Posted September 21, 2018 You want about 10mm sag without you on the bike. If you have it set with no sag the shocks top out and it will feel horrible. 1 Quote Link to comment Share on other sites More sharing options...
johnnyjazz Posted October 10, 2018 Author Report Share Posted October 10, 2018 Thanks shakennstirred. so ive done all my measurements (finally) and i only appear to have 5mm of static sag. they are brand new 40lb falcons on the middle setting on a 1974 ty250a. by stiffening up the pre load will that get me nearer the desired 10mm. my intuition tells me to soften tho to increase static sag?...is this one of those smaller oil ratios=richer mix things? not my area of expertise, obviously. Thanks so much! Quote Link to comment Share on other sites More sharing options...
feetupfun Posted October 11, 2018 Report Share Posted October 11, 2018 5mm sag without you on the bike is fine. The sag with you on it is much more important 1 Quote Link to comment Share on other sites More sharing options...
johnnyjazz Posted October 11, 2018 Author Report Share Posted October 11, 2018 (edited) oh brothers, my ineptitude at this stuff is getting embarrassing. I'm sorry. if pictures speak louder than words then maybe you can tell me if this looks ok? i used the rear fender as a point of fixed reference and the nut on the shockie as the other. first me off, second me on. i just want it to be right. i went over a speed bump in the city today at 30mph and im sure it bottomed out. am i asking way too much of 40lbs falcons in NYC traffic? you guys are the best. thank you. Edited October 11, 2018 by johnnyjazz brevity Quote Link to comment Share on other sites More sharing options...
feetupfun Posted October 11, 2018 Report Share Posted October 11, 2018 It's important what "on" means when you are doing the sag. For a trials bike you need to have all your weight on the footpegs. That means no weight on the seat or the handlebars. You can touch the handlebars to stop yourself wobbling, but don't put any up or down force on the grips. If you did that already and got the 1.5 inches of sag shown in the photos, then you have done very well, nothing more to do. The likely reason why you bottomed out on a speed bump is that you were sitting down, well I hope you were sitting down anyway. Trials suspension is tuned for the rider standing on the pegs. When you sit, the sprung weight of the bike is you plus the bike. When you stand on the pegs, the sprung weight is somewhere between being just the bike and the bike plus you, depending on what you legs and body are doing at the time the rear tyre hits the speed bump. If you set a bike up to resist bottoming on things like speed bumps with rider sitting down, the rear suspension will be way too stiff to work properly when you want to use it for trials-type riding. 3 1 Quote Link to comment Share on other sites More sharing options...
johnnyjazz Posted October 11, 2018 Author Report Share Posted October 11, 2018 (edited) As always, thank you for your time and effort in this stuff feetupfun yes, that was me standing on the pegs, not sitting. i know i can hear the chorus chanting WTF?..just get a road bike you baffoon...why would you ride a TY around the city? that's not what it was made for! i fully understand that. i'm looking at a new bonneville t100 or scrambler shortly but really need the wifes permission and esp good vibes for bike two -not forthcoming right now-...(why would you need two bikes etc) my desired end result is to just make a nice time capsule and put the bike away for my son as an investment. thanks again feetupfun, really makes me happy to know i can just leave them alone. interesting point that jumped to mind tho...if a ty250a with a seated rider will bottom out the shocks at 30mph, i wonder if that was in part due to the failure of the 'long seat trail' cat model? ive learnt the TY was very unsuccessful in the US market. as a pleasant anecdote tho (rare these days), the two stroke scooter shop whose owner kindly does my inspection/mot recently told me his uncle was the head of yamaha canada in the 70s and was a team rider and had great success on the bike. outlaw dave is his name...maybe some of you know him?..it is a small world. anyway, i'll crawl back under my shell for now.....steering bearings next, tho if the swing arm slid out effortlessly im presuming they're ok but why not check em anyway?..... again, to reiterate and defend myself against a few borderline condescending comments in some of my other posts, i do take the point that 'if it ain't broke don't fix it', but also am well aware that if you want to learn to swim you actually need to get in the pool at some point and get wet. i set myself the goal of wanting to learn and educate myself about how engines work, ultimately 4 stroke road bikes to save in horrific and abhorrent mechanic prices in NY (many well over $100 an hr for basic maintenance). Everyone said a two stroke single was a great place to start and the TY250A was the first bike i learnt on in 1986 so when one turned up out of the blue i just impulsively pulled the trigger on it as it was on my doorstep. I just figured do it all now while i have access to a workshop, tools, free gas and storage etc through my job. So far every bit of work i have undertaken on the bike has been a success so my confidence is growing at this stuff. i did manage to make a stand i was quite pleased with too...my back feels better already! best always, johnny Edited October 11, 2018 by johnnyjazz 1 Quote Link to comment Share on other sites More sharing options...
feetupfun Posted October 11, 2018 Report Share Posted October 11, 2018 Nice stand 1 Quote Link to comment Share on other sites More sharing options...
feetupfun Posted October 11, 2018 Report Share Posted October 11, 2018 46 minutes ago, johnnyjazz said: interesting point that jumped to mind tho...if a ty250a with a seated rider will bottom out the shocks at 30mph, i wonder if that was in part due to the failure of the 'long seat trail' cat model? ive learnt the TY was very unsuccessful in the US market. best always, johnny The long seat kit was probably unsuccessful because the footpeg location totally destroyed the off-road handling so you were left with a low performance road/trail bike that had a huge gap in the gears between 4th and 5th. I agree with US Dirt Bike Magazine when they tested the TY250A (in trials trim) and said it made an amazingly good trail bike that would be even better if the gearbox ratios were made like a trail bike (evenly spaced) 1 Quote Link to comment Share on other sites More sharing options...
scifi Posted November 8, 2018 Report Share Posted November 8, 2018 You want the Falcon 'Speed Bump Shocks'... With their 5 inches of movement, they will coast over 4 inch Speed Bumps, without you ever feeling a thing... Just 400 Dollars from your local supplier... Quote Link to comment Share on other sites More sharing options...
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