Ty250 Twinshock Fork Damper Rod Mods

[feetupfun]

A recent post in this forum mentioned that John Shirt had success with improving the fork action on TY250 twinshock forks by using smaller oil holes in the damper rods.

My TY250B and TY175B both have TY250 twinshock front ends fitted with B&J Racing springs but otherwise are standard. The B&J springs made a great improvement in the fork action of both bikes but they still don't seem to be as good as well set up Spanish bike forks of the same era. I weigh 88kg and use 5WT in the 175 and 10 WT in the 250. Oil level in both bikes is 125mm from the top when bottomed.

Does anyone know the size and location of the holes that worked well for John Shirt?

[grouchof]

Hi,

I had the opportunity to open a Majesty 320 fork. I did not notice something special compare to the standard TY250. Shure I did not look very carfuly to the holes.

Regards

[woody]

Apparently, not all Majesty Yams had the forks revalved, more than likely just those used by sponsered riders, the rest had standard TY damping. So if you compare the two there is no difference. I have 3 pairs of Majesty forks and they are all standard. (I'm referring to the 250 bikes here)

If you take the damper rods out of the forks you will notice that at the bottom of the rod there are 2 holes opposite each other which are about 6mm diameter. Near the top of the rod are 2 more, about 2mm diameter. These control the oil flow but what you need to determine is which are for compression and which are for rebound damping. After lots of careful studying over a glass of Tizer, I still couldn't work it out.

So I thought I would employ the trusted trial and error method. As a starting point with mine I reduced the 6mm holes to 3mm but noticed no change in damping, they still collapsed and I could still top them out. I may have then tried them at 2mm, can't remember, but whatever it was, still no change.

I then reduced the top holes from 2mm to 1mm. This seemed to slow up rebound damping (too much) but I don't know whether it was solely down to the reduction in the top holes or a combination of that and the already reduced bottom holes. I now had compression which still felt too soft and rebound that was now too slow. It was trial and error all right, but error was way ahead in the race.

It was at this point that I turned to alcohol, lost all sense of reason and boomerang'd the forks accross three of England's finest counties and fitted the TY Mono front end.

The twinshock forks can be made to work well as I have ridden a bike with the damping modded and it was very good. You just need someone who can work out how the oil flows and then reduce the size of the appropriate holes accordingly. Easy...