More power required

[motofox]

Hi Guys, my first post here and you seem to have a great forum full of usefull info and advice. I've just got my lad a 2004 XR125 so he can get to college when he's 17. However I was more than a little shocked about the lack of performance when I took it out for a spin. 50-55mph on the flat and 60-almost 65 down hill. Now I think this is a tad dangerous so I'm looking at any tuning tips.
Is this bike restricted or is that just how they come? I've had XRs and XLs years ago and none seemed as slow as this. When he gets on this bike he will be shocked at how slow it is because he's used to winning races on tuned 250/450s. I don't mind spending a few quid because these motors are very strong and will last. Please don't tell me to sell it and get a 2-stroke.
I've been told upping the gearing makes a difference as the motor won't rev but with the lack of bhp I'm not sure it would pull this.
HELP

[bobsmith90]

Hi guys,

First post here too! Just got myself an xr125l as well and am well chuffed with it (my first bike and all that). Motofox, sounds exactly like the type of speed mine can go. On a flat dual road I rekon I can nearly push it to 60mph (prob more like 55-60) but no furthur to be honest. I think thats all these bikes can do.

I've been searching on other forums as well to see if anyone has any tuning tips and apart from replacing the air filter and possible exhaust no one has done anything else with them. Replacing the filter and exhaust don't seem to have any effect on the top speed at all whatsoever.

I'd be interested to find out if you do come across any way of improving the speed as it'd be nice to have a bit more out of it on the bigger roads. Having said that, on most roads I go on (city and suburban) it is perfect for me at these "restricted" speeds. I'm only learning as well (although at slightly older age of 33).

[AlanH]

Is this bike restricted or is that just how they come?

It's how they are. 11 horses and around 120 kilos. There are benfits though. They are good on fuel and almost bulletproof. Tuning options are limited so if your son needs something quicker then he would be better off getting through his test asap and getting something a bit bigger.

Please don't tell me to sell it and get a 2-stroke.

Now would I do a thing like that

[motofox]

To be honest we are a bit concerned about how he will ride on the street. He's used to carving his way through back-markers and keeping the wire tight everywhere. Maybe thats whats needed on his ride to college? or maybe not? It is possible his tweaked 450 could be made street legal(ish) but with rebuilds at 30 hours it wouldn't be a very sensible option.
For now I'm sure with our tuning contacts the little XR could be made to get up and go a little better. But I guess it must be me getting older anyway I'm sure my XL125/TL125 seemed much, much quicker than this bike.............is it really the same motor?

[AlanH]

Considering he'll have no problems with the basics of riding, I would have thought he'd be a good candidate for an intensive course with a hire bike and then going straight onto something bigger when he passes.

The problem you'll have restricting a race bike is not the 25kW (33 bhp) limit but the power to weight ratio limit of 0.16 kW/kg. Even restricted to 33bhp, lighter bikes are still not legal due to the power to weight ratio.

Once he's on a bigger bike, he should get straight onto a Bike Safe course and, with a bit more road experience, something like RoSPA or IAM would be good. Hopefully that'll give him some challenges and promote some interest in developing his road skills rather than just thrashing the poor little XR125 flat out everywhere.

When I taught CBT, some of the best young riders that came through had grown up riding bikes on the track or off-road. On the other hand, some of the worst young riders had grown up riding bikes on the track or off-road. It all depends on the attitude.

[motofox]

Yep! I guess he'll have to put up with drafting milkfloats until he can pass a test. I will make sure I get some pics of him with Ls on though. I can blackmail him with his competitors untill he passes.................
"Win or the pics come out of the van"

[catteeclan]

Hey Motofox. You wouldn't be Dave from Caister with a son doing the biz in Supermoto?

[jasonbc]

To be honest we are a bit concerned about how he will ride on the street. He's used to carving his way through back-markers and keeping the wire tight everywhere. Maybe thats whats needed on his ride to college? or maybe not? It is possible his tweaked 450 could be made street legal(ish) but with rebuilds at 30 hours it wouldn't be a very sensible option.
For now I'm sure with our tuning contacts the little XR could be made to get up and go a little better. But I guess it must be me getting older anyway I'm sure my XL125/TL125 seemed much, much quicker than this bike.............is it really the same motor?

Thats offroad competion riding, not road riding and if you suspect he's going to ride like that on the road then the power of the 125 will be ample until he's learnt enough road riding skills to stay rubber side down and out of A&E

[Warthog]

Thats offroad competion riding, not road riding and if you suspect he's going to ride like that on the road then the power of the 125 will be ample until he's learnt enough road riding skills to stay rubber side down and out of A&E

Have to agree.

First off, a 125 4-stroke is never going to burst adrenaline glands and secondly there is racing and there is riding.

Everyone is pointing in and going in the same direction in a race: the expect to be overtaken at close quarters....
On the road, as we all know, there are drivers who don't even know motorcycles exist who can't wait to do a U turn or hang right without even checking their mirrors (those things in cars used to see if your big-mac got on your tie...)

Your son will need to learn the difference between the two and it sounds like you may need to help him. We've all been that age and we all thought we knew more about riding than was the case: I certainly did and had narrow escapes as a result.

As for putting a race bike on the road: I think would be unwise in the extreme.

I know you did not want to hear this, but 125 mopeds can really shift, they are light, are very economical and seem very relaible compared to other 2-stroke engines. Not my cup of tea, but I can see they make sense. I really think you should give this some thought. Otherwise, your son simply has to get used to a slower bike: and resist the urge to take unecessary risks, just to get that extra bike-length in traffic.

Having been a courier in London, I know the risks one takes when one's got one's priorities mixed: it's not worth it.

My 2p

[jasonbc]

Have to agree.

First off, a 125 4-stroke is never going to burst adrenaline glands and secondly there is racing and there is riding.

Everyone is pointing in and going in the same direction in a race: the expect to be overtaken at close quarters....
On the road, as we all know, there are drivers who don't even know motorcycles exist who can't wait to do a U turn or hang right without even checking their mirrors (those things in cars used to see if your big-mac got on your tie...)

Your son will need to learn the difference between the two and it sounds like you may need to help him. We've all been that age and we all thought we knew more about riding than was the case: I certainly did and had narrow escapes as a result.

As for putting a race bike on the road: I think would be unwise in the extreme.

I know you did not want to hear this, but 125 mopeds can really shift, they are light, are very economical and seem very relaible compared to other 2-stroke engines. Not my cup of tea, but I can see they make sense. I really think you should give this some thought. Otherwise, your son simply has to get used to a slower bike: and resist the urge to take unecessary risks, just to get that extra bike-length in traffic.

Having been a courier in London, I know the risks one takes when one's got one's priorities mixed: it's not worth it.

My 2p

When we were in Paris a few weeks ago those 125/250 scooters were everywhere you looked and they weren't hanging around and they cut through traffic like it was standing still. I was very impressed with them and they also seem as if they are the fashion in europe at the moment but don't seem to have caught on over here yet. The only one that i know of is the Suzuki Burgman and thats 400cc over here, maybe they should import a few more as plenty of manufacturers seem to sell them on the continent sucsessfully