I have installed a 15 teeth front sprocket and could not be more pleased with the result. The bike is much nicer to drive since it gained strength throughout the rev range. Continues to 120, without cutting through and it did not lose top speed. The 120 also comes with more ease, and ramps that were impossible to do in the 5th can be made in 5th, and the same for the other gearss. I do a lot less gear changes, so driving is more enjoyable.
The only defect is noted at 120 is a little more noise, but at least I can drive ar 120 stabilized, when before it was complicated.
Note a lot safer when overtaking and the bike shakes a lot less at low speed. The engine brake is also a little stronger which is great on very steep descents.
I believe it will make good fuel economy.
Since I changed the sprocket I have clean the chain and the sprocket area. Disgust is the right word, the bike has almost 2 years and 10,000 miles and was never clean, and I always put more oil than it needed...
Sorry about my English and comment.
