TY 250b airbox lid

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GSX 1300R
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Joined: Wed Jul 05, 2017 6:49 pm
Bike: 1975 Yamaha TY 250 B
Club: Shoalhaven Classic

TY 250b airbox lid

Postby GSX 1300R » Mon Apr 29, 2019 10:08 pm

Hi everybody Can someone please advise of effects of fitting a ty250C airbox lid to my ty250b The C lid has air intake hole in it The bike has a UNI filter fitted Can I up the jet size for more power Thank you



David Lahey
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Re: TY 250b airbox lid

Postby David Lahey » Tue Apr 30, 2019 5:42 pm

They are pretty sensitive to the amount of restriction created by the airbox. The B model jetting is different to the C and D model jetting and the only difference I've ever found is the airbox design. At one time I had the early airbox with the air entry holes in the side and I fitted a late model lid to it. It wouldn't run properly like that and to get it to run properly, I taped over the holes in the side of the airbox and used the D model jetting.
Less restriction in theory will allow the motor to make more power but good luck getting the jetting right.
Very recently I fitted a 26mm OKO to that bike and am running no airbox, just a pod filter and it runs beautifully. The engine response to the throttle is noticeably faster than it was with the D model TY250 carby. Long term I want to make a large volume airbox but haven't got there yet


relax, nothing is under control

GSX 1300R
Junior participant
Junior participant
Posts: 15
Joined: Wed Jul 05, 2017 6:49 pm
Bike: 1975 Yamaha TY 250 B
Club: Shoalhaven Classic

Re: TY 250b airbox lid

Postby GSX 1300R » Wed May 01, 2019 11:29 pm

Thank you David cheers




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