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Bought a 125. Will I break it ?

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Gazz
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PostPosted: 21:07 - 15 Sep 2010    Post subject: Bought a 125. Will I break it ? Reply with quote

Just bought a 125 recently and wondering if I will damage the engine on it ?

Where I live there is a dual carriageway and whilst on that road tonight, I noticed that when doing 60 mph the revs are at 9K rpms (the bike red-lines at 10K). Obviously I could go slower, but it just feels normal to be doing those kind of speeds on this road - to keep with traffic etc.

The bike feels quite comfortable getting up to 60 mph and gets there efficiently enough for what I am looking for, but the revs are starting to get me a bit concerned.

Ideally I think the bike could be doing with an extra gear to help it along a bit, but what I was more worried about was how much punishment will the bike take before it packs in since the engine is working at around 90% for quite a long period of time.

I use this road quite a lot, so the bike will be doing this on a daily basis.

Any advice much appreciated.
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Cheeseybeaner
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PostPosted: 21:27 - 15 Sep 2010    Post subject: Re: Bought a 125. Will I break it ? Reply with quote

Gazz wrote:
Just bought a 125 recently and wondering if I will damage the engine on it ?

Where I live there is a dual carriageway and whilst on that road tonight, I noticed that when doing 60 mph the revs are at 9K rpms (the bike red-lines at 10K). Obviously I could go slower, but it just feels normal to be doing those kind of speeds on this road - to keep with traffic etc.

The bike feels quite comfortable getting up to 60 mph and gets there efficiently enough for what I am looking for, but the revs are starting to get me a bit concerned.

Ideally I think the bike could be doing with an extra gear to help it along a bit, but what I was more worried about was how much punishment will the bike take before it packs in since the engine is working at around 90% for quite a long period of time.

I use this road quite a lot, so the bike will be doing this on a daily basis.

Any advice much appreciated.


I wouldn't worry about it. If its a 4-stroke 12hp bike it isn't an especially highly tuned 125 anyway, some of the 2-stroke sports 125s make 30 plus hp which is pushing it for the engine size and they do rely on periodic rebuilds.
High revs don't necessarily mean engine abuse, its just the way the engine is designed to operate, shorter strokes as is typical of bikes mean higher rev ceilings etc etc. They are designed to rely on revs.
I would routinely use my 125s and 250s flat out on motorways and dual carriageways and it wasn't really a problem. They're designed to be used safely at somewhere near maximum capacity as 125cc more or less dictates this to you. High revs doesn't necessarily mean engine damage particularly when the motor concerned is in a comparitively low state of tune anyway.
You could fit a larger gearbox sprocket if you wanted though I wouldn't think it worthwhile.
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Chalky.
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PostPosted: 21:28 - 15 Sep 2010    Post subject: Reply with quote

Are you really fat?
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ms51ves3
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PostPosted: 21:40 - 15 Sep 2010    Post subject: Reply with quote

Ride it until it blows up, then you will know the answer.
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johnsmith222
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PostPosted: 21:46 - 15 Sep 2010    Post subject: Reply with quote

avoid motorways and only do around an indicated 50mph. That's what I would do if I were you.

It doesn't do a bike any favours to be at full revs and top speed for a long time.
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Cheeseybeaner
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PostPosted: 21:49 - 15 Sep 2010    Post subject: Reply with quote

david_m213 wrote:
avoid motorways and only do around an indicated 50mph. That's what I would do if I were you.

It doesn't do a bike any favours to be at full revs and top speed for a long time.


Depends purely on the design. A 125 is designed to be run at 'high' revs most of the time, it has to be. Since most are limited to 12 or so hp I don't think he needs to worry.
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johnsmith222
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PostPosted: 22:02 - 15 Sep 2010    Post subject: Reply with quote

Cheeseybeaner wrote:
david_m213 wrote:
avoid motorways and only do around an indicated 50mph. That's what I would do if I were you.

It doesn't do a bike any favours to be at full revs and top speed for a long time.


Depends purely on the design. A 125 is designed to be run at 'high' revs most of the time, it has to be. Since most are limited to 12 or so hp I don't think he needs to worry.


I disagree. Some mechanical sympathy is definately needed. I have a fair bit of experience in destroying 125 4t engines.
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Nexus Icon
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PostPosted: 22:03 - 15 Sep 2010    Post subject: Reply with quote

I always get nervous about receiving a lapful of piston after a few miles at NSL.
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Notj7
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PostPosted: 22:16 - 15 Sep 2010    Post subject: Reply with quote

I am interested in this also, please forgive the thread hijack. I also heard that the piston can fly off and if it does, that's your testicles (and possibly your life) gone, because we're leaning right over the tank flat to maintain that speed...

I have a 4T 125 - mine also redlines at 10k (same bike?)...

Riding at 9k is 70mph. The engine and exhaust get really hot (obviously) and I feel like I'm murdering the poor thing. Can someone put my mind at rest as there are many mixed opinions here...
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Paulington
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PostPosted: 23:43 - 15 Sep 2010    Post subject: Reply with quote

I have witnessed a 100cc watercooled kart engine spit its piston out the cylinder head at 21k RPM. Lest it be known I wouldn't like to be over that.

Don't drag bikers wear kevlar vests now for just this issue?
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badas
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PostPosted: 01:02 - 16 Sep 2010    Post subject: Reply with quote

i own n use an old 125cc 2 stroke nearly daily and prety much hit 50 to 60mph a few times in the week in my travels and i also get up to 8K revs and have been doing this for just over 2 yrs, not rebuilt the bike once since owning it and its still performing the exact same as i first bought it.

only thing i have done is change spark plug and engine oil

spark plug replaced twice and engine oil once (should be more often i know)

but still.... i stay out of the red lines but its still running perfectly.... touches wood Very Happy
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neil.
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PostPosted: 05:06 - 16 Sep 2010    Post subject: Reply with quote

My YBR has over 30'000 miles on it now, I've had it since it had 500 miles, and I commute 60 miles a day, a good 75% of which is spent at 50-60mph on dual carriageways. Never needed any work on the engine, bar oil changes at every 2'000 miles and valve clearances at every 4'000 miles, new plug and air filter every 8'000, as per the service schedule. Smile

10k = somewhere between 65-70mph on mine, 50mph = 7k, 60 is around 8.5-9k (can't remember exactly).

Re: Piston flying out, has anyone actually got a real account of this happening on a 4t 125, or is it just hear-say?

Now, what I have heard is that these engines will snap their cam chains after a while, doing all sorts of nasty stuff to the insides. But again, I know of no actual real-life examples of this, just what people have told me.
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Cheeseybeaner
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PostPosted: 07:50 - 16 Sep 2010    Post subject: Reply with quote

Quote:

I disagree. Some mechanical sympathy is definately needed. I have a fair bit of experience in destroying 125 4t engines.


Possibly some but any 12hp 125 should be happy running at 60mph most of the time. There's very little revolving mass on a small engine like this and they're in a low state of tune anyway, much much lower than some of the sports 125s.
It would be akin to saying you shouldn't run a 500 at 90mph all day on the motorway say, which in my experience isn't a problem.
They're designed to be used somewhere near full capacity most of the time, lets face it you can't use a 125 in any other way.
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Cheeseybeaner
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PostPosted: 07:53 - 16 Sep 2010    Post subject: Reply with quote

neil. wrote:
My YBR has over 30'000 miles on it now, I've had it since it had 500 miles, and I commute 60 miles a day, a good 75% of which is spent at 50-60mph on dual carriageways. Never needed any work on the engine, bar oil changes at every 2'000 miles and valve clearances at every 4'000 miles, new plug and air filter every 8'000, as per the service schedule. Smile

10k = somewhere between 65-70mph on mine, 50mph = 7k, 60 is around 8.5-9k (can't remember exactly).

Re: Piston flying out, has anyone actually got a real account of this happening on a 4t 125, or is it just hear-say?

Now, what I have heard is that these engines will snap their cam chains after a while, doing all sorts of nasty stuff to the insides. But again, I know of no actual real-life examples of this, just what people have told me.


Piston flying out!? Ha ha ha. I'd love to see that occurring on a 12hp learner 125!
As you say most 4 stroke 125s are very durable and will happily run up a high mileage without much hassle.
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kingsknight
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PostPosted: 12:21 - 16 Sep 2010    Post subject: Reply with quote

My XR125 has 22k on the clock and I'v done 13k of that myself in the last 19 months! The bike spent most of its time at 55/60mph never had any engine problems!

The engine sounds as good as it did when i got it at 9k!

You will be fine!Unless its a cheap imported bike then it will blow up in about 10 miles with you on the floor bleeding to death because the frame snapped and the engine fell on your head!
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Muscle Bike Rider
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PostPosted: 12:39 - 16 Sep 2010    Post subject: Reply with quote

My Varadero is now up to 24,000 no worries at all still rides exactly as when I got it, just the usual service etc.
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Rowey
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PostPosted: 13:34 - 16 Sep 2010    Post subject: Reply with quote

Just keep up with the oil changes and servicing. Might be an idea to let her warm up a bit before ragging it on the dual carriage way.

Could also try getting lower over the bike to reduce drag. Or get a small screen for the same reason. Dropping a bit of weight would help too. Also try altering the gearing. All of those things might help, but then again they may not.
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Gazz
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PostPosted: 17:59 - 17 Sep 2010    Post subject: Reply with quote

Chalky. wrote:
Are you really fat?


90-ish KG
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stevo as b4
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PostPosted: 21:50 - 17 Sep 2010    Post subject: Reply with quote

Definately do not worry about it! If its a 4stroke 125 then it will need oil changes every 1000m if you want to really look after it, and clean out the oil filter in petrol if it's a metal gauze type. If it's a paper cartridge then just replace it each time. My old CG125 was ridden flat out everywhere for 18months, and that was 60mph on the flat, or 70mph on a long downhill. My mate used to ride his 60miles a day on the motorway to work, and his was an older but slightly faster one than mine. Valve clearances need checking about every 4000m, but thats it really.

You cannot blow up a well maintained decent running bike that is looked after, not abused and warmed up properly. Any engine failure's with all this considered are just bad luck and not a fault of the design, the rider or the bike IMO.

If it's a 2stroke then pretty much the same applies tbh. It needs more maintainence and looking after with decent oil used, and the carburation and oil pump settings need to be correctly set up. But aside from more careful warming up a performance 2stroke is just as durable, just it has a finite re-build interval as part of it's routine maintainence.

You never see anyone say that it's bad for the life of a 600cc sportsbike engine to be ridden at 160mph all the time and that you should not use full throttle or rev it to the redline regulary if you want it to last. I will accept that 100bhp has a far easier time propelling a rider and bike at legal speeds than a 12bhp engine does, but a hard ridden 600 is just as reliable as a hard ridden 125 and vice versa IMO!
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