Installed on RC 2018. The crem de la crem of spark plugs. Engine smooth, power on demand has improved, acceleration unbelievable and a clean start. Worth the money, combine with the NGK caps for optimum performance. Matt

Ordered these from Norway. Super fast delivery and responses from the team during the order process. The caps together with uprated coils and iridium spark plugs have made a big difference. Cold start much easier and engine feels snappier 🙂

Installed on RC 2018. This will be longer than most reviews but want to get all the details down to help you guys decide. Ladies and gents, the big ticket item on here for the GT family. If you enjoy performance and speed, then my god is it worth it. The damping and preload makes bumps and crests effortless, no bottoming out and chain is free to do it's thing. I have managed to test it here in Ulster on the road race tracks (not when closed roads sadly) and it performed like a dream, ride flows from section to section, cornering is massively improved, I can't fault it. Adjustment is relatively simple, I'm 85kg/6 ft4 so some adjustment/firming was needed out of the box, but all very straightforward, plus a higher set ride height is noticeable for me. Installation is one for one with OEM, would recommend mechanic there to give the bones and links a once over/lubrication and for an extra pair of hands. It is a larger price tag, but it's not everyday we get a company like YSS making a specific product for Hyo's. If you are on the fence, then definitely go for it.

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 😉

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!

So got this set few weeks ago as i wanted a bit longer gears. im using it in city, heavy traffic, daily commuting. Before was changing gears like a lunatic 1st to 4th non stop.. this set sorted my problem a lot to be fair. 20-35(40 with screaming engine) mph in 3rd gear. 2nd gear comfortably around 25.. unfortunately havent tried whats the max speed now as grown up life sucks and havent had time to push the bike yet

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 🙂

It really does make big difference I’m just not sure about the front sprocket Because I see the one on shop it has 14teeth I recited 13teeth But I’m very happy about this upgrade Thanks Marcel

Wow such a huge difference, finally changed this myself. Not too scary. Straight swap for old kit. Didn't even need a gasket. Much sharper gear changes and acceleration. I highly recommend. On a scale of 1 to 10 it's about a 6 in mechanical knowledge. Remember to soak the plates and don't over tighten the bolts. It's a full oil change so have at least 2 litres handy

Highly recommend to install this kit. The clutch reaction is much better, lever is more stiff, clutch action is more punchy. Super nice feeling when you change the gears. I have the impression that the bike is less jerky on 1st / 2nd gear when you ride with small speeds. I love the kit and I'd do that again without any hesitation