are they restricted?

[rpg]

hi, are 4 stroke 125s restricted or are their modest top speed of about 60mph a true representative of their speed? is it only the 2 stroke 125 that are restricted?
thanks

[yorkshirelad3]

my 4 stroke 125 is restricted to the L plate limit of 14.6bhp.

so i guess they are

[mchaggis]

Very few, if any four stroke 125s are restricted, because they simply don't produce more power than the learner limit. As such, 65-70 mph is pretty much max for them.
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[VFR400UK]

Modern ones are not.
Some of the ones from the early 80's made more than 14hp but i dont think these were ever restricted

[Kickstart]

Hi

Not really restricted, just not really capable of producing much more power than 11kW.

All the best

Keith
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[Jack_Cheese]

Most will be built to comply with the limit, others restricted. Can't see a 125 4t pushing more than 20bhp in derestricted form

Jack
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[lilredmachine]

Mine is bang on (or slightly over, infact it's illegal) the limit, at 15HP. It's very torquey though and good fun to ride, have also had 80 on the flat confirmed by a friend on a zxr-400, thanks to a long 6th gear (I was indicating 86). They can be modified, but they become money pits and lose their reliability which apart from the noise they make, is about the only advantage (IMO) that they have over 2 strokes.

The MZ is a dohc motor, with a 4 valve head. with a grand, it could be 150cc, loud, 21HP and capable of 90+. Though I could just buy an old 2 stroke for £600 and do it that way, see what I mean?
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[rpg]

what is your bike lilredmachine?

[lilredmachine]

An MZ SM 125. The picture below was taken today.
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[phantomtek]

Nice bike, and a lovely view to boot.

[yorkshirelad3]

mines a hyosung comet gt 125 v twin. this is restricted to 14.6 break horsepower but can be taken out to 21bhp but at the loss of reliability.

Im just going to leave it as it is and get a restricted 600

[rpg]

lilredmachine-great bike! Thanks for posting the pic.
yorkshirelad23 would your hyosung be tuned at 21bhp or is that just with the restrictors taken out?

[Kickstart]

Hi

That would mean tuning the absolute nuts off the engine.

All the best

Keith
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[lilredmachine]

Not necessarily, the 125 is the 250 sleeved down. The 250 I believe produces 27+ horsepower.
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[MarJay]

[yorkshirelad3]

the bike will get to 21bhp with the restrictors taken out. Hyosung dealers mechanic can do it. only problem is, he says he will see me in 5000k for a rebuild!

[Kickstart]

[lilredmachine]

[mchaggis]

[Jack_Cheese]

I'd guess the 21bhp the hyosung dealer claims is the engine power measured at the crank. Though i reckon it is possible for a 4t to produce 20bhp derestricted. I think the cbr125 is restricted down from 18-20 to the 14.6 limit. Any cbr 125 owners had their machines derestricted?

Jack
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[Kickstart]

Hi

The CBR125 is not restricted. It does not even make as much power as the learner limit. 13hp at 10000rpm.

21hp sounds like a mechanics think of a number game to me, and not actually measured anywhere (or measured with one hell of a correction factor added).

All the best

Keith
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[lilredmachine]

The problem with the Honda Cg125, sorry, the CBR125 is it's heritage. No matter what paintjob they stick on it, it's still a toy with a pepped up CG motor that is 2 horses short of the learner limit, and when you could only have 15 horsepower in the first place, 2 horsepower is a lot. Plus the fact it only produces that at the crank, so it would be even less through the rear wheel, and at 10,000 RPM the mirrors would fall off with vibration.

I would love a 2 stroke sports replica, but I'm happy with mine until I can pass my test and get on a bigger s'moto. A 4t 125 is perfectly good for getting around, just don't expect too much as what you get is what you get.
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[Kickstart]

Hi

The CBR125 engine has virtually nothing in common with the CG125 engine beyond the makers name.

All the best

Keith
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