December 5, 20223 yr My recently purchased 1975 Yamaha Ty250 appears to have an enlarged aftermarket reed valve intake. I had to cut a new carb to air cleaner boot by about 15mm to get it to fit without crimping. Does anyone know what brand of aftermarket "performance" reed valve upgrade blocks would have been common back in the day. Or does anyone know of someone who still provides a block and reeds that would fit? My current reeds are frayed and broken.
December 5, 20223 yr Aftermarket reed blocks are/were not a common mod on the twinshock TY250 motor. Many people fit aftermarket reeds to the standard reed block. Standard TY250 reed blocks are readily available second-hand. Sounds a bit like it might have a reed block spacer. That would move the carby rearwards
December 6, 20223 yr Possibly other Yamaha reed blocks / rubber inlet manifolds from the DT, RD ranges could have been fitted as a perceived upgrade, or just because of availability ?
December 7, 20223 yr Author Thank you for suggestions. I'm picking the bike up from storage over Christmas and will post pics and part measurements then.
December 9, 20223 yr On 12/7/2022 at 7:29 AM, djr said: Possibly other Yamaha reed blocks / rubber inlet manifolds from the DT, RD ranges could have been fitted as a perceived upgrade, or just because of availability ? Reed cage for the TY250 are the same part fitted to RD350s
December 10, 20223 yr On 12/9/2022 at 8:39 AM, tony27 said: Reed cage for the TY250 are the same part fitted to RD350s Yes, you are right. I have had various Yamaha's over the years. Bolt pattern for the reed cage & rubber inlet is often the same pattern , allowing sometimes bigger / longer rubber inlets to be fitted from a different & sometimes more popular model. I could be wrong , but seem to remember having a TY175 or 250 , which had a DT175/250/360/400 ? rubber inlet that bolted straight on and allowed a bigger carb to be fitted You also have some of the YZ and RD ranges from various years that may have identical parts , or interchangeable but larger parts
April 25, 20233 yr The TY 250 was notorious for having a strangled induction (too many twists etc). So the best way forwards was to improve the induction route to smooth the passage of air to the intake port. Some riders said at the time that the engine was too responsive when modified and needed taming down. Now a days it might be too tame!
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