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

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

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.