winkie Posted May 9, 2006 Share Posted May 9, 2006 Hi everyone, I got my first bike today and really cracking one in perfect condition and only done 10k. The bike is a 1999 Yamaha SR 125 and I am going to use it to pass my test. I rode round today and i think it may be restricted, got up to about 55mph and it doesn't really pull that well, which is why i think it is restricted, its' runs perfectly. Does anybody know if this is restricted and can it be de-restricted and how much of a job it is ? Cheers Steve Link to comment Share on other sites More sharing options...
Moderator YamaHead Posted May 10, 2006 Moderator Share Posted May 10, 2006 to the forum Steve Now I'm sure I'll be corrected on this, since I'm obviously from the other side of the pond But I've done this de-restriction trick to a few brand new Trials Bikes right outta the crate....when I worked for a local bike shop a few years back. My 1st guess would be to have a look inside your exhaust header pipe......since you've got a Single, that shouldn't be too much of a prob. There might be what is best described as a big flat washer just inside the pipe where it bolts onto the head. This substantially restricts the air flow out of the exhaust port.....hence reducing your HP Now like I said earlier......I'm sure some other more qualified Brit member will be along to verify my suggestion ..... But it is a fairly easy task to pull that exhaust header pipe to have a look in there for yourself Hope this helps Link to comment Share on other sites More sharing options...
Moderator drewpy Posted May 10, 2006 Moderator Share Posted May 10, 2006 Hi everyone, I got my first bike today and really cracking one in perfect condition and only done 10k. The bike is a 1999 Yamaha SR 125 and I am going to use it to pass my test. I rode round today and i think it may be restricted, got up to about 55mph and it doesn't really pull that well, which is why i think it is restricted, its' runs perfectly. Does anybody know if this is restricted and can it be de-restricted and how much of a job it is ? Cheers Steve far as i am aware, the sr125 is built to have 12hp, the only other way is tuning it. easier to buy a bigger bike like sr250 or sr500. Link to comment Share on other sites More sharing options...
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