Hey guys. I've got the K-pipe 125 here in Denmark and i have some news for you. I haven't written about it here, since there are no subforum for it yet.
First of all, it has only 6 kW and a top speed of 90 km/h @ 10.000 rpm and i'll tell you a bit about why.
The power of the engine is restricted by the diamensions of the carb and intake and by the camshaft.
The carb is only 17,5mm which gives a restricting effect from only 6500 rpm (500rpm above max torque), because the air speed in the intake passes 0,3 times the speed of sound. A 20 or 24mm would be more fit for a 125cc and specially when is has to go up to 10.000 rpm, where it has to suck in the air in a very short time. I am very curious if the diameter in the intake tract of the cylinder head continues to be this small, but Kymco has put a security bolt to fasten the manifold so i can't remove it and check at the moment.
The intake valve is only open for 150 degrees because it closes before the end of the intake stroke and the exhaust valve way too long time before the exhaust stroke is done. Also there is no valve overlap but a couple of degrees between the closing of the exhaust and the opening of the intake. This suggests that they have not been able to comply with the emission control with a carburated engine while still keeping the power high and the cost low.
I do not know much about the exhaust, other than that the pipe from the engine to the silencer has an outer diameter of 25mm and that the outlet from the silencer has an inner diameter of 17mm. Visually, the exhaust on the 125cc looks identical to the 50cc model sold in Germany and other European countries, but since it is not sold here in Denmark i cannot find any data or anywhere to measure to compare.
The top speed is limited both by the low power output and because the highest gear (4th) has an output 0,96 while the chain sprockets are 14-36. I am about to mount a 34-tooth rear sprocket which should give a 6% speed increase, which is what the dealer said i should go for to not loose to much power. Because the wheel is already in the position closest to the engine, removing two teeth behind can be done without having to shorten the chain.
The top speed at the moment in the original state is a stable 90 km/h @ 10.000 rpm if the wind is in the back or it is downhill, 93-96 km/h if lying behind a truck on the highway. If the wind is in the face the top speed will fall to 70-80 km/h when i'm trying to keep an aerodynamic body position. My weight is 56 kg and then i'm equipped with a leather suit, a flip-up helmet with sun visor, leather boots, leather gloves and a 1,3m steel chain, putting the total weight added to the weight of the motorcycle at around 80 kg. This makes me conclude that this is a kind of ideal scenario.
Also, don't try to go above 90 km/h. The engine vibrates noticebly above 9.500 rpm and a lot above 10.000 rpm. Below that, there are no problems with the vibrations though.
When looking away from the engine and speed, there are both good and bad things.
The speedometer is off by 15%, which is kind of a lot because it is a digital speedometer.
The headlight has a design flaw which means that you partially blind yourself when using the long light.
The gearbox is with a centrifugal starting clutch and a pedal-activated main clutch, which gives some opportunities for very fast gear shifts, but requires the rider to learn to drive this way, since you have to engage every gear and have to keep the gear pedal pressed if you want to unclutch. More of that if we get a subforum to this. It was wierd at first, but now i'm comfortable with the gear box and can use it properly to my advantage.
The ride is very comfortable with soft front shock absorbers and a kinda hard rear spring, but i haven't had a passenger with me yet. I can see that the passenger has to have kind of short legs though because the footrests are kind of close to the seat.
I've got both the workshop manual, the parts list for the 125cc and the parts list for the 50cc as pdf files if anybody want them. I can see from the workshop manual that it may have been planned to be with a rear disc brake but is now with a drum, so i guess it can be possible to get a disk conversion kit when it's been fully introduced to all markets.
Anyway, the bike feels good, comfortable, safe and of good quality, but it can be felt that this bike is made in a way to minimise costs. And it is really cheap.
I won't fill this thread with too much of this bike, but if you want to see pictures and videoes, you can see my thread
here, but it is in danish, so you might be forced to use a lot of google translate.
I'm looking very much forward to seeing it launched in the US, because there will be more parts on the market, which will eventually leak to Europe.
