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Hello everyone, I am planing to put 180cc big bore kit, putting second radiator and putting bigger injector, what is your thoughts?
And meybe someone has a foto how they mounted second radatior?
And will the coolant come to the engine from the second radiator?
Btw i heard if you put bigger injector you do not need a powercomander
And how much will i need to do warming up on the 180cc to fully send it

Sorry for my english its not the best

Have a good day :))
 

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to be fair i dont think u need another radiator. A friend of mine had 182cc kit, stock cooling on the r125 is pretty good so that wouldnt really be a problem.
You can get powercommander ECUs instead of new injector, much cheaper and easier.. Remember to get a better air filter as well.



EDIT: And perhaps a better camshaft would clearly make the engine perform better + more fuel + more air and a good exhaust system with DB killer.

To be honest i dont think its worth it. My r125 now does 145 ish with 15t front sprocket and a aftermarket exhaust and a newoverhauled engine( yes its ridden in, wouldnt be redlining if not), i guess its gonna go slower after riding a couple thousand kms. Of course it doesnt do 145 on hills etc, but with some tailwind and perhaps a little slope, itl do 145+-

ALSO, the bike feels like its gonna fall apart going that speed. The frame isnt made for such high speeds, and it just feels unsafe. It also vibrates and feels like the engine is gonna fcking blow up at any time.
These bikes neither has steering dampers, so its really easy to get tank slappers on this one.
 

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What a frightening proposition to do double the speed of what a bike was designed to do from the factory!

You can buy after market steering dampers if that worries you, but the stresses on the engine, gearbox and drive train will be massive. And I presume that with a different front sprocket the bike is painfully limp at low speed/revs.

The R125 is too light as a package, and it feels light on the road at times. Especially when I compare it to my other bikes which are designed to crack mega speeds. They feel more planted as the speed increases, and they feel safer, solid, and confident as you pass 100mph. But physics dictates that as something moves faster it also becomes lighter.

My R125 has remained standard from the day I bought it. But if I did want to make it quicker. Or should I say better I would give the engine more mid range poke which would mean you don't have to work the gears quite so much to make progress on tight twisty roads. Maybe a maximum top speed of 90mph would be better for those occasions when you want to use a section of a motorway to get somewhere quickly.

The R3 has been around for quite a few years now, hence repairable or spares adverts are commonplace. I wonder how easy it would be to fit the R3 engine in to the R125 frame? "Street Sleeper"
 

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Captain slow, No, there is no problems at low rpms with one more tooth on the front sprocket (Im 90kgs aswell), but it doenst accelerate as good, and very steep hills are putting the engine to a test sometimes, but i never feel like its struggling to be honest. The reason i got a 15t sprocket was to be able to commute on highways at a slight lower rpm when doing 90kmh. Went from 7k to around 6.4k or less at that speed.
 

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2008 YZF-R125 (180cc)
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> My R125 has remained standard from the day I bought it. But if I did want to make it quicker. Or should I say better I would give the engine more mid range poke which would mean you don't have to work the gears quite so much to make progress on tight twisty roads.

k+n, exhaust and a PCV, with a dyno tune to tie it all together did exactly that for mine. On the fuelling map you can see a big diagonal section in the middle/midrange where they added more fuel and it really woke the bike up under 8k, where before there was nothing really happening. I guess it's an emissions thing?

r125_midrange.jpg

I ran a 15t on the front for a while too and it was actually pretty nice in the lower gears, but my bike didn't really have the oomph to get into the rev range in top gear to make use of the extra top end so it wasn't really worth it overall, though highway cruising was a bit more chill. It's pulling way better since the new clutch though so i might have to re-test.

Fair play on 145km/h on it!! I managed 136kmh/85mph one time downhill with favourable wind on a 15t, but then I was also fully loaded with luggage and rucksack so maybe it would have gone quicker without all the extra weight & drag. 145 must have been bouncing off the limiter ;)

>Maybe a maximum top speed of 90mph would be better for those occasions when you want to use a section of a motorway to get somewhere quickly.

yeah it would be nice if a-roads or whatever (where unavoidable) were a bit less painful, and that you could cruise with normal traffic flow but really that's the only issue I have with the bike and it's not really a problem that often. It's only a question of about 10mph extra though so seems a bit daft to have to get a different bike for that. hence thinking 180 kit.


>The R3 has been around for quite a few years now, hence repairable or spares adverts are commonplace. I wonder how easy it would be to fit the R3 engine in to the R125 frame? "Street Sleeper"

I wondered the same, given the cost of a 180 kit and all the question marks around it I think the price might be comparable but I *think* the R3 motor is a fair bit wider than the r125. Not saying it isn't possible but the spacing of the frame rails might be a problem for motor mounts, pipework and such.
 

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2008 YZF-R125 (180cc)
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if you mean me, I don't have ignition maps afaik (I know dynojet do an ignition controller but whether it works with the R125 idk either... though I'd like it to!). I can send you the fuelling map but ignition is something I don't yet have control over.

if not me, nvm, my bad :)
 

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the PCV only does fuelling afaik and even that's only a % difference from stock, doesn't say what stock is, or anything about ignition, sorry. Could be in the service manual perhaps?

You running a speeduino by any chance?
 

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good luck using the same gearbox, clutch etc xD
The r125 gearbox is quite shite and the clutch will slip as hell. Ive owned 2 R125 engines now, and both of them had strange gearboxes. Get some reinforced clutch springs at least or it will slip.. I dont think the crankshaft would love a 200cc setup either, but hey its not my bike.
 

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My R125 has remained standard from the day I bought it. But if I did want to make it quicker. Or should I say better I would give the engine more mid range poke which would mean you don't have to work the gears quite so much to make progress on tight twisty roads.
k+n, exhaust and a PCV, with a dyno tune to tie it all together did exactly that for mine. On the fuelling map you can see a big diagonal section in the middle/midrange where they added more fuel and it really woke the bike up under 8k, where before there was nothing really happening. I guess it's an emissions thing?

View attachment 33336

I ran a 15t on the front for a while too and it was actually pretty nice in the lower gears, but my bike didn't really have the oomph to get into the rev range in top gear to make use of the extra top end so it wasn't really worth it overall, though highway cruising was a bit more chill. It's pulling way better since the new clutch though so i might have to re-test.

Fair play on 145km/h on it!! I managed 136kmh/85mph one time downhill with favourable wind on a 15t, but then I was also fully loaded with luggage and rucksack so maybe it would have gone quicker without all the extra weight & drag. 145 must have been bouncing off the limiter ;)

Maybe a maximum top speed of 90mph would be better for those occasions when you want to use a section of a motorway to get somewhere quickly.
yeah it would be nice if a-roads or whatever (where unavoidable) were a bit less painful, and that you could cruise with normal traffic flow but really that's the only issue I have with the bike and it's not really a problem that often. It's only a question of about 10mph extra though so seems a bit daft to have to get a different bike for that. hence thinking 180 kit.


The R3 has been around for quite a few years now, hence repairable or spares adverts are commonplace. I wonder how easy it would be to fit the R3 engine in to the R125 frame? "Street Sleeper"
I wondered the same, given the cost of a 180 kit and all the question marks around it I think the price might be comparable but I think the R3 motor is a fair bit wider than the r125. Not saying it isn't possible but the spacing of the frame rails might be a problem for motor mounts, pipework and such.
Any chance you could email me this map?
 
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