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Oh baby. It shifts like butter.
Aw yeah....
After having increasingly worse 2nd gear issues on track at high rpms, where it felt like my rear tire was spinning out and the bike was trying to buck me off it became clear that my poor bike had fallen victim to the classic first generation R6 2nd gear slip problem. Hundreds and hundreds of bikes have had this issue, to the point where there was an effort at one point to sue Yamaha. With some bikes, it happens with as little as 5,000 miles on the clock, but more typically around the 20,000 mark. There are only 3 gear dogs on these bikes, which are prone to rounding off, then causing 2nd gear to slip. This was remedied on 2003 and newer R6's by adding 2 more gear dogs for a total of 5, and some have resolved it by having the gears undercut as well.
I located a guaranteed good condition used 2005 transmission, ordered up all the gaskets and hardware from RonAyers.com (which was awesome to deal with for OEM stuff) and enlisted the help of Eric Baker, our local first gen R6 expert .
After an epic ride to North Reading toting my lead filled messenger bag crammed to the brim with transmission parts, we set about pulling the engine. The front sprocket nut was a pain in the butt, but after some serious wrestling was overcome. After pulling and splitting the engine, we were able to access the tranny. At first inspection, it was easy to identify the problem. 2nd gear dogs were sure enough rounded off, and one of the shift forks was worn horribly. Half of the thickness of it was sheared off from repeated wear... Aha. That's where all the metal bits in my engine came from.
Everything went back together well, except for ending up covered in gasketmaker and we replaced the right and left side engine covers with NRC's. I had to replace the oil filter again due to someone overtightening and mangling the nut on the K&N (thanks Ted for meeting me Sunday!) and threw in a magnet for good measure. Hopefully the fresh oil, filter, magnet, and manual removal of metal bits from the engine will be enough.
Once engine was back in the bike, it was easy enough and I overcame my fear of not knowing where to put everything back. It wasn't that bad. Bike started right up without a hiccup. I wanted to jump for joy on the way home... 2 days of wrenching, $175 in parts, and my bike shifts awesome. It is now clear that it hasn't shifted right since I got it, so it will be great to have more faith in my machine and focus on just riding, rather than compensating for mechanical issues.
Thanks a million Eric for spending your entire weekend on this project. I sincerely appreciate it.
Pictures below:
Worn shift fork:
New case cover:
Almost ready to go: