December 30, 201510 yr Hi All, Got a bit of an issue with my TY175 forks (previous owner largely, seems to have been a bit of a butcher) anyway, long story short i've gone through everything and restored the bike, but having issues with the forks topping out. I have rebuilt all and assembled as per the 'fiche but when I try and 'hop' the bike the forks top out completely. What fork oil are people using and how much? Or is there something else that I should be looking out for! Thanks, T
December 31, 201510 yr other things that might be related are: People have been known to add extra fork spring preload, which will increase the likelihood of topping out There should be anti-topping springs on the damper rods, which may have been removed
December 31, 201510 yr Damping on the TY was never the best so don't have high expectations. I have played about with different oils but eventually just accepted that progress has been made since the Seventies and lived with it. No doubt they can be made better but it will involve engineering rather than juggling oils. I had thought about a set of yokes and forks off the 250 then fitting one of the cartridge adaptations now available. I cured the problem with a set of Betors (attached to an SWM Edited December 31, 201510 yr by 2stroke4stroke
December 31, 201510 yr Maybe the fork springs have sagged with age and use. You could get a new pair with a "poundage" suitable for whatever weight you are and that should solve the problem.
January 1, 201610 yr Author Thanks all for the suggestions, I have a bottle of SAE30wt fork oil, so will try that and see what happens...
January 1, 201610 yr Going to fill the front of my 175 with 30wt this afternoon to see what it does.I just bought it fully restored and have no idea what is in there.I will post back the results.
January 2, 201610 yr The forks/front end always was the weakest thing on the 175 if you started to push it hard. The damping is of a fairly old design (no surprise considering the age of the bike) as such it needs the thicker oil to work. If you have strong enough springs to stop it bottoming out it tends to top out. It might be worth trying different amounts of oil. So long as you put enough in to cover the damper piston then you can use the air gap as a secondary spring. This does require the o ring seal in the top cap to be in good condition. As 2stroke4stroke suggested it would require a fair amount on engineering work to fully upgrade the forks to modern damping and springing. Although I'm sure with some inventive thinking it could be upgraded.
January 9, 201610 yr Forks filled with 10w30 as per the manual.50mm spacers on top of the springs with an air gap of 125mm.Clanging noise is gone doing little wheelies.I guess they knew what they were doing in 1976!
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