iest1 Posted August 7, 2007 Share Posted August 7, 2007 Just got new xt125 and after owning a 125 before was expecting a bit more speed, but can't get the bike over 45ish! Is this because it's restricted, still running the engine in or a bigger problem? Any help would be appreciated. Also any1 else's speedo stop working? Link to comment Share on other sites More sharing options...
YamahopperTheHorrible Posted August 21, 2007 Share Posted August 21, 2007 Just got new xt125 and after owning a 125 before was expecting a bit more speed, but can't get the bike over 45ish! Is this because it's restricted, still running the engine in or a bigger problem? Any help would be appreciated. Also any1 else's speedo stop working? This is a small engine but with the right gear ratio you can get them up to the 60mph range. Providing that the engine is running properly. If everything sounds good then check the usual, plug gap, compression, etc... Once that is determined you can look at changing the gearing with a smaller rear sprocket. If the bike is used you will probably need to replace the chain and sprocket(s) anyways. You will loose some low end but gain high. Look at opening up the air box or getting a K&N air filter and rejetting if nessecary. I have a chinese 150 stroker copy that gets about 65 but i had to swap out the rear sprocket for a smaller one. Easy speed gain. Link to comment Share on other sites More sharing options...
mat-earl Posted August 21, 2007 Share Posted August 21, 2007 an xt125 shud do at least 75mph derestriced without mesing with any gear ratios as a few of my fiends have them and top end they were just slighty quiker than my old dr wich did 70 Link to comment Share on other sites More sharing options...
YamahopperTheHorrible Posted August 21, 2007 Share Posted August 21, 2007 an xt125 shud do at least 75mph derestriced without mesing with any gear ratios as a few of my fiends have them and top end they were just slighty quiker than my old dr wich did 70 Didn't know they were restricted? Second question is why is a 125 cc bike sold restricted, different laws in different countries? The only reason bikes are sold here in the U.S. restricted is either to make them legally sold as a moped or for a beginner bike. I didn't think that these were being sold as beginner bikes. Is the restriction on the exhuast - a round washer type disc welded into the header? Link to comment Share on other sites More sharing options...
trooper6967 Posted August 21, 2007 Share Posted August 21, 2007 Didn't know they were restricted? Second question is why is a 125 cc bike sold restricted, different laws in different countries? The only reason bikes are sold here in the U.S. restricted is either to make them legally sold as a moped or for a beginner bike. I didn't think that these were being sold as beginner bikes. Is the restriction on the exhuast - a round washer type disc welded into the header? yep in the uk a bike up to 125 is classed as a learner bike and at 17years+ on learner plates and a cbt (compulsary basic training) this is all you can ride untill either you pass your lightweight motorcycle test which then entitles you to ride i think a bike of no more than 33bhp for three years then i think you can ride bigger bike, or at 21years+ you can just take a direct access normally on a er5 or a 600 bandit which once passed you can ride anything. but if a 17 year old passes his lightweight cat he can ride anything as long as it is restricted to 33bhp (if they can afford the insurance) but can you imagine a gsxr600 restricted to 33bhp it wouldnt be worth it lol and as for the xt 125 being slow even restricted it shouldnt be that slow but if it is the case than your man here should be right as thats were they usually restrict them. a road legal race exhaust or drilling the restrictor out i would have thought would do it? Link to comment Share on other sites More sharing options...
mat-earl Posted August 21, 2007 Share Posted August 21, 2007 if am not rong there wil be a restricer in the exhasut and 1 on the air inlet of the carb Link to comment Share on other sites More sharing options...
jinxed Posted September 29, 2007 Share Posted September 29, 2007 Yes, the restricters will limit the bike to 12hp I suspect, so removing them should give you more. But, you should get more than 45mph from a 12hp 125! Have you ridden alongside someone to verify that the speedo is accurate? When you say "new" do you mean brand new, or new to you? My 20 year old SR125 is extremely sick, but the speedo still shows 55 when it maxes out. (Hold your laughter please!) It looks like I have finally found someone I can beat though!! Can I race you? Please! Just the once!! Link to comment Share on other sites More sharing options...
yoda Posted October 1, 2007 Share Posted October 1, 2007 You have switched the petcock on and not got a blockage, have you? Link to comment Share on other sites More sharing options...
fostersmonster Posted October 15, 2007 Share Posted October 15, 2007 a mate has got an xt125, he was having the same problem but then realised his speedo was out by about 20mph!! so got that sorted under waranty, but still not that fast, he gonna trade it in for a dt125 cos thy'll do 80mph no probs Link to comment Share on other sites More sharing options...
Tomo Posted October 15, 2007 Share Posted October 15, 2007 I had an XT125 R New last november. After the run in period it was good for 65 and 70 only at a real push with a bit of a down hill. The speedo packed in after about 500 miles I think it was. This is a common problem and was immediately sorted under warranty. Then the bike was traded in for an R6. No longer have any speed issues Link to comment Share on other sites More sharing options...
sheige Posted November 14, 2007 Share Posted November 14, 2007 finally i found someone with the same problem i have the x model 17" wheels and mine to will only do 45 flat out it seems as if the throttle is restricted but it isnt, say you were in third doing 25 you would be flat out without the bike really screaming and when you change up it will jump forward. i have had the carb off and the rubber block off the head and there wasnt any restrictors to be seen, i have also had the exhaust off and there was nothing in there i have today however taken the silencer appart ripping the guts out and putting a muffler bar with (muffler stuff) so it becomes straight through took it out for a spin and it was still the same. getting desperate now as i have recently passed my test, cant afford my bandit yet and cant go on the motor way with this bike totally dangerous 45mph not good. HELP!!!!.plz Link to comment Share on other sites More sharing options...
Guest Brian Bonner Posted November 14, 2007 Share Posted November 14, 2007 (Scratching head) This may sound like a ridiculously easy solution, get a bigger bike? Anything below 500cc's is supposed to be a learner bike or a mellow bike, so of course they're supposed to be used at the lower end of the speed limit! There's no use complaining about it, that's what they're designed for. Get a bigger bike if you need/want more speed. Link to comment Share on other sites More sharing options...
sheige Posted November 15, 2007 Share Posted November 15, 2007 Thats not an answer now is it! there's obviously a problem with these bikes and buying a bigger bike isnt the answer. For those interested ditch the exhaust gas recirculation pipe on the exhaust close to the head and get the hole welded up this will give a little more. the rear silencer needs to be replaced and the gearing needs to be altered the front sprocket is 14 tooth standard, ive ordered a 12 tooth that should be in tomorrow i will put a post on tomorrow to let you know how i got on. Link to comment Share on other sites More sharing options...
iest1 Posted November 21, 2007 Author Share Posted November 21, 2007 Cheers for all ur input guys, bike is finally fixed. Speedo was knackered n showin 10-15mph less than what i was doing, got new speedo under warranty and all is well. Link to comment Share on other sites More sharing options...
yoda Posted November 21, 2007 Share Posted November 21, 2007 Cheers for all ur input guys, bike is finally fixed. Speedo was knackered n showin 10-15mph less than what i was doing, got new speedo under warranty and all is well. Speedos can and do read 10% fast, so you'll probably hit the sound barrier now! Link to comment Share on other sites More sharing options...
Ferg Posted November 23, 2007 Share Posted November 23, 2007 Thats not an answer now is it! there's obviously a problem with these bikes and buying a bigger bike isnt the answer. For those interested ditch the exhaust gas recirculation pipe on the exhaust close to the head and get the hole welded up this will give a little more. the rear silencer needs to be replaced and the gearing needs to be altered the front sprocket is 14 tooth standard, ive ordered a 12 tooth that should be in tomorrow i will put a post on tomorrow to let you know how i got on. Fitting a smaller front sprocket????? You must want to go even slower. Link to comment Share on other sites More sharing options...
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