Been driving with this for about one year now, and it is amazing how these changed the spark characteristic on the bike. Great product.

The best upgrade you can make on this bike. Those sprockets change everything - acceleration, higher max speed, better rmp/speed ratio. I'm super happy and I'd do it again, anytime. The only suggestion to Marcel I'd have is to offer the front sprocket with rubber to make the chain work quieter with less vibrations. All the rest, 10/10!

Arrived super fast. Plugged in my 125p started the engine, took it out for a ride, amazing indeed, instant noticeable improvement to start up, idle, throttle response 🤗 perfect. Thanks.

Definitely worth it, Bike now drives much smoother, gearing is way better. I would highly recommend to switch to this kit

BUY THIS NOW! I have no regrets, this kit is amazing, amazing, can tell the difference after installing. I had great support and help through the buying, delivery, and installing, and I honestly wish I had done this sooner. And honestly, guys, get this. Ride safe fellow riders!

Fantastic service from marcel. Brilliant bit of kit and would recommend anyone looking to upgrade to buy this kit.

Just upgraded to these coils, the uprated regulator, the uprated stator and ngk caps with iridium spark plugs. I have to say it made an amazing difference, the bike almost no longer needs choke (less than a minute and only on first start in the morning), acceleration has improved significantly and my bike is now charging (which was my original problem :p). Very happy with all items 🙂 Bike is a 2003 gv250 carby model

If you are debating whether or not to get the 520 upgrade then the short answer is YES...get it. If you want to know why you should, continue reading...... I was unsure if the expense would be worth the investment, after all the GV125S in it's self is a decent cruiser and with the stock sprockets I could achieve 67 mph if the weather was on my side. I found it slow getting there all the same and at top end the bike would be hurting.....you could hear that she didn't like being redlined. I contacted Hyo Riders and Marcel was so helpful in arranging the upgrade I needed. Once fitted I noticed I was up to speed much, much faster than previous and the gearing and revs seem more in tune. I find that 4th can be a cruising gear....enough pull to get you along and when needed take you to 60 mph , I only really use 5th for when I'm on open carriageways. I have achieved a top end speed with this conversion of 75 MPH and considering I am 12 1/2 stone , the bike has panniers and a topbox and I am fully kitted when riding, I think that is impressive from a upgrade. At this stage I'm sure I have covered most of what is needed to know.....and in fairness , the promises made as to what this 520 upgrade would deliver have been spot on. Well done Hyosung Riders 10/10. Again a big thank you to Marcel for all his help in this, you are a star....

Instant gains from this kit amazing worth every penny

Easy upgrade