Re: Doubts about Discover 125 ST's engine power

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You really shouldn't be doing all this with the bike still in its run-in period. Complete your run in religiously for the prescribed 2000km and only then think about opening it up the way you have been wanting to. There are people on this forum who have taken the 125ST past its rated 105kmph top speed. I see no reason why your bike shouldn't manage this too.

Re: Doubts about Discover 125 ST's engine power

Hi buddy,

You bike is behaving exactly the way it was designed to. Disco 125ST makes its peak torque at 7000rpms. That is a very high rpm to be making peak torque for a 125cc bike. For comparison R15 makes peak torque at 7500rpms (but that is a sports bike) & Honda Shine makes its peak torque somewhere around 4500-5000 rpms.

What this means is that your engine makes low torque at low rpms. This is the reason why you feel that you have to twist the accelerator hard when climbing slopes for the bike to go. This is also the reason why after 50kmph your bike suddenly feels stress free, because the engine comes into the power band where it can create enough torque to pull the bike.

The advantage of this engine set up is that you can have extra gears on the bike (hence 125ST has a 5th gear) and you can create more power at top end (which is why the claimed power at crank is 13hp). Unfortunately this also means that you have to rev the balls off this kind of engine to really be going anywhere (just as you are experiencing).

The ideal cruising RPM for your bike is 6500rpms. So whatever the speed is at that rpm in top gear, rest assured that your bike can do those speeds totally stress free and relaxed all day long. However where ever you need torque or acceleration (drag racing, carrying heavy pillion, climbing hills), then remember that you will have to rev the engine to around ~5000rpms to get anywhere. If you can ride sanely, like an uncle, without accelerating much and keeping the revs below 4000rpms then you will get very good FE, maybe around 60kmpl. If you keep wanting to accelerate on this bike by revving, your FE will drop.

Also a side effect of this kind of engine is that because of revving, the engine is going to make a lot of noise (that's what you are hearing). However you will have to live with that, that is just the kind of engine your bike has.

Finally, to close I want to give you an example of Karizma and P200NS. Karizma makes its peak torque at 6000rpms and max power at 7000rpms, whereas P200NS makes peak torque at 8000 rpms and max power at 9500 rpms. Karizma cruises at 100 kmph at 6000rpms whereas P200NS does the same at 7000rpms. Karizma makes only 17bhp max whereas P200NS makes 23.5 bhp, still both bikes make the same torque at different RPMS, 18.3 Nm. This means that if we cap the rev limit to 6000 rpms then Karizma will beat P200NS hands down every single time. But in reality that never happens because P200NS red lines at 10000 rpms where as Karizma red lines at 8500 rpms. This is just the way the engines are designed and this is their respective characters.

I could go into much more detail but I will stop now. Hope this helps.

Re: Doubts about Discover 125 ST's engine power

@plasmabhai
U sir, have a really cool and funny name, and a great deal of knowledge. Thanks for all that info.
One more question is, will this kind of engine be able to take that much beating of high revving? Will it last long? I know P135 is that kind of engine only. 4 valves and needs to be revved hard. How has the P135 performed in engine longetivity department?

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I have seen videos of people making 0-60 on their discovers run only 500 km. Will such stunts seriously damage the engine?

Re: Doubts about Discover 125 ST's engine power

Hehe, thanks!

Actually these engines are totally designed to take it. It is just in the nature of such engine to perform as they have been designed. The Disco 125ST especially is more suited with its 4 valves making it breath easier and hence reach higher rpms faster.

AFAIK P135 has never been shown to have longevity issues. I know at least one person here in xBHP who has pulled a Saddle Sore on his P135 apart from doing more crazy stuff on it and I think his bike is running top notch.

As long as you keep the engine stock, feed it good oil whenever it requires and carry out all maintenance properly and as required, almost all modern engines whould run till 100,000 without any problems whatsoever.

Running in an engine properly is actually very important. People who do that (make 0-60 videos without properly running in engines) will lose out on a little bit bit of power, some bit of smoothness and a lot of reliability in the future. Of course they will blame the bike later on for something which was their fault in the first place.

Re: Doubts about Discover 125 ST's engine power

Shantanu, all relevant info has already been put forth by plasma sir (), I'd just say - take care of your bike; it'll take care of you. Keep your wrist in control till at least 1500 kms. Do vary the rpms though! You should do 50 in 3rd, 60 in 4th from time to time, so that the engine parts get mated properly. But not for long durations.

A proper run in will guarantee you a niggle free ride for years down the line (engine perspective) is merely an under-statement.

Re: Doubts about Discover 125 ST's engine power

Bhai..!! kya bhai...!! Itni bhi mat lo meri..!! Haha!!!

Re: Doubts about Discover 125 ST's engine power

u should follow the run in procedure mentioned on ya user manual...revving up the engine excessively during run in period can hamper optimum performance of the bike....what u have to understand is that during run in of a new bike...the bike is learning to accept piston timing and blast chamber combustion...so its your job>>>I repeat>>>YOUR JOB to carefully "train" your bike with love n care.. ....if u had a new born...would u shove a bowl or rice in its mouth or expect it to run like a 12 year old?? no rite?? same with ya bike....and the run in procedure is there for jus that....another thing....discover isn't a full sports bike...its a semi sports...semi tourer...so it provides optimum power and mileage at low speeds and low rpm....stability n mileage at mid rpm n low speeds as per gear shifting pattern...n a very conservative fuel consumption at high speed with high rpm.......so..take care buddy...ya bike is a part of u....treat it with care n love ...........ride safely...