TY175 questions but reed valves in general. In talking to a reputable engine builder he said that "in his experience a softer reed pedal worked better for trials applications." I have replaced my stock reeds with a set of  Boysen reeds but couldn't feel any difference, thoughts? Could you tell a difference or is it an accumaltive increase with each little bit making it some what better? I didn't get to ask him about the metal reed stops on the reeds, would the work better in the stock positions or would they work better if you "bent" them so they would open wider or again would it be a waist of time and energy? This is all in search of the just a little more low end grunt!

Thanks for any reply/info you might share. 

Changing the reeds to boyesen makes a small difference to the way the motor runs. The evidence of this is that the air screw and sometimes the pilot jet requires a change made when boyesen reeds replace the standard reeds. The difference is because there is less pressure drop through boyesen reeds because they are lighter. Maybe it is too small an effect to be noticed on your bike.

When you fit boyesen reeds, the reed stops need to be removed for them to work properly.

Maybe you are asking about bending the reed stops when using the steel reeds? That's not a good idea because it reduces the time-to-failure of the steel reeds and might allow the reeds to bend instead of flexing within their elastic limit.

Low budget gains in bottom end response on a TY175 which is in good mechanical condition include increasing the compression ratio, lightening the flywheel and experimenting with the ignition timing.

 

The mouth of the reed block can be carefully opened out by about 3mm possibly more ( its been a fair while since I have done this mod so choose your dimensions carefully) this allows a significant improvement to air flow into the intake port. Boysen Reeds are best as they don’t tend to wreck the engine if they break off…unlike the spring steel originals. Always bent the reed stop plates  when fitting Boysens by about 4mm never ran without the stop plates. This mod we did to TY’s LC 2/350’s and RD 400. Take great care of the stop plate fixing screws you don’t want them getting inside the motor. Do any of these mods at your own risk.