Starting with the quality of the wire work, excellently put together. As for longevity, I made this switch around 4k miles when my stock regulator went out. I decided to just replace the stator as well. (The stator provided by Marcel was a ElectroSport USA stator] It has been three years since I've had these parts and they have continued to hold up. I blew one regulator fuse(THANK YOU) and that is from pushing the bike to the absolutely limit(6 months ago) on a speedrun to get to an Autoparts shop for a drainplug for my car before they closed. If you are looking to replace the stock reg and stator I would trust the work put out here. They know where to find quality parts. If it wasn't for wanting to not mess with this again, I would pick up a Shinden set that is still floating around here.

Where do I start? The beginning I guess 😉 I bought this Beauty, a GV125-S last Month and was not happy with the Power and acceleration, or should I say missing Power of the 14 PS compared to my last ride a Yamaha XV 125 with 11 PS. Dont get me wrong I noticed the difference, but she was just laggy, screaming at me, and the Vibrations when going above 8000 Revs. In 5th gear she hit 10-11000 revs and just stopped power wise, not going any faster than 105 Km/h on the dial. In the German Group on Facebook it was suggested to upgrade the front Sprocket to one with 15 teeth, which I did, She run a little smoother through the Gears and the Engine sounded a bit quieter and wasnt screaming at me, but the loss in Power in the lower Gears, especially going from 2nd to 3rd, and the Top speed of 110 Km/h, which took me ages to get there, wasnt satisfactory, taking her up into the Red again to get here.. Then I saw Marcels post in that Group and decided to buy this Upgrade from the UK and have it shipped to Germany, thanks to Marcel here for the support. What can I say? I took her out on a 3 Hour ride to test, what a difference! The smaller front Sprocket (13) and the Larger Rear Sprocket (Dimension) and 520 Chain is the perfect combination. She shoots up through the Gears, no Jerking, no screaming Engine, next to no Vibrations, just smooth and fast, at 9-10000 Revs in 4th Gear she hits 100 Km/h and in 5th I had her at 120 Km/h and felt like there was still more .... plus it was a windy day 😉 I also ordered the NGK Spark plugs and HT leads which just finishes off a perfect combination. Thanks Marcel and Team, Season nears its end and I just cant wait to get out there next year, the Bike is so much fun now and I dont miss my Yamaha at all 😉

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!

After a little bit of a struggle I finally got the kit on! Thanks to the forum post that front sprocket was a right ass to get off! The bike feels much nicer to get up to speed, it feels a lot smoother and nicer to ride! So far I’ve noticed an increase of about 5mph on the top speed but I haven’t pushed it to see how far it will go but that extra 5mph gives a more comfortable carriageway experience. Highly reccomend!

I've added this upgrade onto my bike it's perfect only thing I found was that the front sprocket was a little loose even with the washer. I'm hearing some noise but unsure if it's the upgrade so I can hear the chain go more now if if there's a problem. ============== Admin Reply: Thanks for your feedback, glad you love it like others do!💎 - If your font sprocket has a rattle, please investigate your drive shaft itself, we don't know if your own previous sprocket splines caused any issues to it etc, remember the original OEM sprocket from Hyosung is made in China, another owner made his bike chain adjustment too tight and he lost his engine shaft, so it was a mess! (his own fault) but the original sprocket was badly worn even inside the spline teeth connecting to the front engine shaft , so double check your setup! Remember to check chain slack and keep it lubed well!

Chain worked well for a few months, had 85mph on flat, compared to normally 65, however it's been roughly 3 months and now the chain isn't holding between rides, tightened it and became slack at the end of the same ride, resorting to a max of 65 down hill, have taken 2 links out and tighten with chain slacking still got the same problem, not impressed by the quality of the chain, in total I've done less than 600 miles on this chain. Admin Edit = Customer bought kit in July 2026 and reviewed in September 2026 ,we are waiting to hear from customer about their bike configuration at the rear end (if badly worn cush drive was at fault , or carrier bearing or too tight chain adjustment, or chain was skewed // instead of straight || etc ) - We supplied a world class AFAM gold chain made in EU, so 600 miles is worrying for us and not good. Fortunately, the sprockets are fast and appear intact, we will await their reply for us to investigate the "chain" premature wear.