TY250 Fork Improvement

Need help finding information or parts for that old machine in your shed? Someone in here will know!

Moderator: Moderators

Stanm
A grade participant
A grade participant
Posts: 121
Joined: Wed Jan 14, 2004 10:17 am

TY250 Fork Improvement

Postby Stanm » Sat Mar 22, 2014 11:10 am

Hi Folks
Although I am not unhappy with my fork set up at present i am looking for some improvement . So I am finally going to buy some new bits for my Twin Shock forks.
I would like some advice on what is the best way to go. I think I would be pretty lucky if one person has compared the options I have below.

The options I am considering are:

1/ Magical springs and damper rods - magical web site is up now - I had some problems buying From Majasty web site. Anyone bought anything for Magicals lately??
2/ Wirth springs ( German) and damper rod mod I read about online
3/ BJ racing Springs and damper rod mod I read about online
4/ France classic trials ( not sure if these are same as Magicals) and damper rod mod I read about online.

Also are the Magical Damper rods much different to the originals.

I am currently favoring the Wirth ones as they also recommend the oil type and quantity.

Any feed back would be appreciated along with options i have not considered

Cheers



Guy53
A grade participant
A grade participant
Posts: 180
Joined: Tue Nov 09, 2010 4:22 am
Bike: Ty250A
Club: ATAQ

Re: TY250 Fork Improvement

Postby Guy53 » Sat Mar 22, 2014 10:14 pm

Hi Stanm
Read the post in product review Cartridge emulators for 1970s forks by David Lahey

I bought the kit and I am ready to test it but there is still snow and the Outlook for today in 5 to 10 mm more.

Guy



Stanm
A grade participant
A grade participant
Posts: 121
Joined: Wed Jan 14, 2004 10:17 am

Re: TY250 Fork Improvement

Postby Stanm » Sun Mar 23, 2014 6:06 pm

Hi Guy
Did not notice the Cartridge eliminator topic. Very interesting and another completely different option.

Thanks for letting me know. I would be interested in your feed back on them. I will keep an eye on that post.

Cheers



Guy53
A grade participant
A grade participant
Posts: 180
Joined: Tue Nov 09, 2010 4:22 am
Bike: Ty250A
Club: ATAQ

Re: TY250 Fork Improvement

Postby Guy53 » Sun Mar 23, 2014 11:41 pm

I bought the kit and I am ready to test it but there is still snow and the Outlook for today in 5 to 10 mm more.

This morning it's minus 10 celcius and ho yes I, made a mistake yesterday, yes we receved snow ( close to 10 ) but cm not mm.
As soon as I can test I will, and I will try to find a rocky section take a little '' film '' , one with the standard setup and the same with the new setup.
I will keep you inform.

Guy



David Lahey
Champion
Champion
Posts: 3543
Joined: Thu Jun 05, 2003 7:01 pm
Bike: Many Twinshocks
Club: CQTC Inc, RTC Inc
Location: Gladstone, Queensland

Re: TY250 Fork Improvement

Postby David Lahey » Tue Jun 17, 2014 8:18 pm

Last week I tried out a new setting on the gold valves in some TY250 twinshock forks at a trial that had lots of small rocks. The setting change was to reduce the preload on the gold valve springs from one turn to zero turns, which is also what someone ended up with on their TLR forks. I reckon it was a further improvement from the one turn setting as far as action on the small to medium rocks, being very supple, but it has lost a little bit of bottoming resistance on landings on drops that really load up forks. I'm going to persist with this setting to see how it goes for the next few trials.
I did some back-to-back testing with a Sherpa T on my practice sections at home the day after the trial and I reckon the fork action with the gold valves set to the new setting was just as good or a bit better than the Bultaco forks.


relax, nothing is under control

Guy53
A grade participant
A grade participant
Posts: 180
Joined: Tue Nov 09, 2010 4:22 am
Bike: Ty250A
Club: ATAQ

Re: TY250 Fork Improvement

Postby Guy53 » Wed Jun 18, 2014 7:24 pm

I David, I also change the preload on the standard ( not painted ) spring to 1/2 a turn instead of 1 turn, I also found quite a difference on small rock, but I did not have enough time to realy test the new setup. The work on the house is now done and I should finaly have a couple of afternoon to test before our next event. I will post my result when the testing is done.

Guy



David Lahey
Champion
Champion
Posts: 3543
Joined: Thu Jun 05, 2003 7:01 pm
Bike: Many Twinshocks
Club: CQTC Inc, RTC Inc
Location: Gladstone, Queensland

Re: TY250 Fork Improvement

Postby David Lahey » Sat Jun 28, 2014 8:19 pm

I rode the first day of a 2 day trial today where there were lots of sharp-edged rocks which was great to try out the settings on the Gold valves. Compared with the standard TY250 forks setup, the front end was noticeably better on the rocks, and no different on other surfaces


relax, nothing is under control

TriCub
Expert participant
Expert participant
Posts: 273
Joined: Fri May 28, 2010 11:38 am
Bike: Triumph
Club: Wester districs trials club

Re: TY250 Fork Improvement

Postby TriCub » Sat Jun 28, 2014 10:46 pm

Have you ever put this much effort into tuning the damping with the stock damper setup? Seems to me that with the spring backed off that much it kid of defeats the purpose for the valve being there at all.



TriCub
Expert participant
Expert participant
Posts: 273
Joined: Fri May 28, 2010 11:38 am
Bike: Triumph
Club: Wester districs trials club

Re: TY250 Fork Improvement

Postby TriCub » Sat Jun 28, 2014 10:53 pm

Have you tried drilling out the low speed holes in the valve and adjust the spring in a bit more to control the high speed a bit better?



JC1
Expert participant
Expert participant
Posts: 321
Joined: Tue Apr 26, 2011 4:15 pm
Bike: Bul, KT, TY
Club: wdtc
Location: Toowoomba, Qld

Re: TY250 Fork Improvement

Postby JC1 » Sun Jun 29, 2014 3:12 pm

TriCub wrote:Have you ever put this much effort into tuning the damping with the stock damper setup?


I've often wondered about that too George, tho not with regard to David & his TY. But rather, modifying the OEM damper rod instead of fitting a cartridge emulator or PD valve, especially on Jap forks, mainly cos its cheaper & I think considerable improvement can be made on the damper rods. As we know, Jap forks of the era typically had too much compression damping & too little rebound damping, so they haudraulic-lock on compression then spring back too quickly as well.

I've often wondered if drilling out the compression holes (a little at a time) then experimenting with heavier oil would give significant improvement to both compression & rebound control (after experimenting to get the right 'mix'). I know it wouldn't cope with the 'spikes' as well as the emulator/PD valve or give any progressive damping like they claim to give, but one should be able to get a fair bit of improvement over OEM Jap forks.

When I got my KT going recently, I intended to try this very thing, but first I compared its damper rods to those of a spare set I have from a TY250B. The TY had only two holes (6mm dia ea) whereas the KT had four (ea slightly larger than the TY's if I recall correctly but like a dill I didn't record what dia!).

Knowing the KT was renowned for having soft front suspension I wasn't going to drill them out any more (at least for the 1st go), but used heavier oil than most seem to use (12wt) & was quite impressed with how supple the forks seemed, on both compression & rebound. Not as good as Betors but much better than typical Jap forks of the day, including std TY forks I tho't. I wonder how much better other Jap forks could be with compression holes modified to be similar to the KT's.

I intend to try something similar on my TY175 when its up & running.


"Men are never more likely to settle a matter rightly than when they can discuss it freely"


Return to “Twinshock & Classic Trials”

Who is online

Users browsing this forum: Google [Bot] and 19 guests