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yzf r125


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or buy a bigger bike, i find thats the easiest way to get more speed, i tuned a few 125s and never found it anywhere near as good fun as say,, an rd 350 with stan stephens gear all over it. i'd save my money on mods to wee bikes and spend it on something bigger. then of course, :huh: i'm old and wise now

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I agree on not wasting money on tweeks for a new 125. Save your cash, keep the bike tidy and standard, do your A1 test, in two years time get a nice bigger bike. I spent 300 quid on my exhaust for my CBR125 and another 40 on a air filter. To be honest the exhaust and air filter added hardly any power, sounded nicer but performance wise, its hardly noticable. I dont see the point of tuning 125s for the road. Most vehicles on the road will go faster than a 125 any way. The best way to make your 125 go faster, is to take extra training, road positioning etc.

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Hmm well i got my A2 licence but im not sure what to do because i havent had this bike for long and i spent quite a bit of money on it already. Plus im on finance so im sorta stuck. I would like to get a bigger bike though ;) but considering my insurance is 350 fully comp i think it quite a money saver for insurance considering im only 17 :)

Mite aswell wait out my 2 years restricted then try and get an R6 after the 2 years restricted is done :D

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@ Beadle: sounds a good idea, dont jump ahead of yourself with a big bike, you have all your life for that just gain as much experience as posible. My restriction comes of in december so i might just keep my DT till then because its fast enough for what i need at the moment plus its cheap to run and tax :D

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  • 1 month later...

ive been hunting around for this thread and was helpfully pointed to it again.

im not 100% sure how the air box mod benifits the engine.

From what i can tell, its talking about the valve system which connects to the exhaust. Ive just had my bike back from 1st service and i asked about that box. I was told its an air circulation system, where air is taken from the airbox and piped out directly into the exhaust. When asked what the purpose was for, its so fresh air can bypass the engine, out into the exhaust, for a cleaner emission result.

But i have been told

"Getting rid of it can help slightly (and make it rather easier to get the fueling right), just don't expect large increases.

There are 2 reasons for similar systems. Either to feed fresh air into the exhaust and complete combustion, or to feed exhaust gases back into the engine to reduce combustion temperatures (reduces the emissions of oxides of nitrogen). "

Im considering getting a LeoVince exhaust sometime soon, so will know then if this system has the same return pipe on the exhaust.

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Yea i noticed that. The bore kit comes with a Race mapped CDI unit aswelll. Aparently acording to some one on this topic (i cant remember who) said that the race ignition unit made the R125 do 90+ mph so with that and the 170 big bore kit for the yamaha i guess you would be looking at about 110+ MPH maybe more but im not sure to be honest. The down side to that 170cc Big bore and the race CDI unit is that it costs £500. I have already spent a fortune on my R125 with the Micron exhaust costing £300 and i do not really want to be spending much more on a 125 when i can wait and save up for a bigger bike. I dont think its worth spending aload for a 125 also considering its my first proper bike otehr then a ped.

Also you was talking about that air recirculation box that is connected to the standard exhaust. When i bought my exhaust system it came with a plastic bung and instructions saying to seal the pipe that connects that air box to the manifold/mid pipe. I asked a few mechanics aswell and they said this should release maybe a few BHP probably about 2 or 3. Its not much but its something. The most i have had out of my R125 with the exhaust system is 84 MPH i could have got more but i didnt push the bike into redline because it dont sound healthy lol.

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Thanks for that infomate, so from what it would seem, simply cutting that tube to the exhaust and blanking it off both side could be benificial. The only reason I can think of is it would only allow the air into the engine, and more air would certainly give better performance albeit just a slight improvement. Not bad I suppose for a free mod. I'm. Personally won't be chabging bikes for a long while so would like to tune up this one.

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Ok, ive taken the plunge and have blocked off the pipe. After tracking back the tube toward the airbox, ive notice it fits into the side of the throttle body. From what i can see, it just bleeds off some of the air coming in so the engine isnt get the full amount.

For those who dont know what weve been talking about, i took the liberty of taking a few pics for you to explain.

After removing the right hand side panel, youll see the side of the engine. Up on the top half youll see this black box mounted on a bracket. This is the "air valve" (second pic down).

If you still unsure, look down at the exhaust from the front and youll find this black rubber pipe (which im holding) Follow that back and youll hit the air valve.

100_3805.jpg

All i did was chop out the middle section of the rubber pipe, and left enough tube at each end to plug it up with.

On the valve side, i simply use a plastic bung i had lying around. This was a perfect fit. I re-fitted a clamp around it just to make double sure.

100_3802.jpg

Down at the exhaust end, i simply used a short bolt with the correct diameter to match the tubing, and also clamped that too.

100_3803.jpg

Hopefully, it might feel a tad better, especially with a headwind....... uphill!

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  • 4 weeks later...

Ok, ive taken the plunge and have blocked off the pipe. After tracking back the tube toward the airbox, ive notice it fits into the side of the throttle body. From what i can see, it just bleeds off some of the air coming in so the engine isnt get the full amount.

For those who dont know what weve been talking about, i took the liberty of taking a few pics for you to explain.

After removing the right hand side panel, youll see the side of the engine. Up on the top half youll see this black box mounted on a bracket. This is the "air valve" (second pic down).

If you still unsure, look down at the exhaust from the front and youll find this black rubber pipe (which im holding) Follow that back and youll hit the air valve.

100_3805.jpg

All i did was chop out the middle section of the rubber pipe, and left enough tube at each end to plug it up with.

On the valve side, i simply use a plastic bung i had lying around. This was a perfect fit. I re-fitted a clamp around it just to make double sure.

100_3802.jpg

Down at the exhaust end, i simply used a short bolt with the correct diameter to match the tubing, and also clamped that too.

100_3803.jpg

Hopefully, it might feel a tad better, especially with a headwind....... uphill!

VERY USEFUL INFOMATE, CHEERS

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VERY USEFUL INFOMATE, CHEERS

i did this temporaly and the engine did not seem right so i put it back on, but did the yamaha techs say it was ok to do or was it dangerous to the engine? also what in power gain did or does it give

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  • 3 weeks later...

on the side where oil filter is located you have to remove the fairings, once this is done you wil see a pipe coming from the exhaust it conects to a little black box and you have to remove the 2 pipes running from it, then undo the 2 screws holding it together, and you will see a kind of diafram inside, i found a metal plate in there and was restricting the ammount of air going through it, so i adjusted the metal plateso the diafram opened fully to let more air into the airtake system. once all back together i tested it out and the results were not massive but very positive on respose and made it ride quicker than it was, and the top spped i had with oncoming wind was 85mph @10,000.

before doing this i was doing 83mph @10,500 rpm so allthough not massive but more responsive and a good find for everybody.

also removed the exhaust and there was not restricton on this apart from the cars, which when i get full system will make it even better.

good luck guys cos this is so easy to do and will liven up your bike, try it and see. let me know how things go

If you go onto e-bay theres a american performance company that will supply you with a boost chip giving you an additional 25bhp to your yzf-r125 ,for a small price of $22.98 us dollars ,i ordered mine and cant wait to see the improvement .

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If you go onto e-bay theres a american performance company that will supply you with a boost chip giving you an additional 25bhp to your yzf-r125 ,for a small price of $22.98 us dollars ,i ordered mine and cant wait to see the improvement .

also ive tried the other one , were,s you alter the diapram and it works very well but i feel there,s more life in this little bike so i am going to have her remapped and that should make all the difference .dont bother with the exhaust , there better quick and quite if you know what i mean

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also ive tried the other one , were,s you alter the diapram and it works very well but i feel there,s more life in this little bike so i am going to have her remapped and that should make all the difference .dont bother with the exhaust , there better quick and quite if you know what i mean
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hi all,

any one know of any mods for the R125 that are in production for 2009??

theres gotta' be more than exhausts and dynojets!?

does anyone know if renthal will be making sprockets for this bike ?

cheers,

<>Chris

edit : just found out renthal do make sprockets for R125 so dont worry about that part :) ( only make standard sizes at the moment though:( )

well if you go on to e-bay theres an american performance company selling a boost chip giving you an additional 25bhp . it sells for $24.98 us dollars, .

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  • 2 weeks later...

well if you go on to e-bay theres an american performance company selling a boost chip giving you an additional 25bhp . it sells for $24.98 us dollars, .

sounds like the 'resistor' chips you can get for virtually anything fuel injected. Dont bother.

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  • 3 weeks later...

Hi, have been reading this thread for a while, and had to put another 50p in the meter and,,,,,,, :rolleyes:

could you start again, I'm sure I'm getting it, I'm a bit slow you see :mellow:

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