Today I installed these upgraded, Bosch Type II injectors, which have four tiny holes to disperse fuel versus one for the originals, and I believe I read they have a slightly higher flow rate than the originals:
http://motors.shop.ebay.com/osidetiger/m.html?_nkw=k75&_sacat=&_odkw=&_osacat=0&bkBtn=&_trksid=p3911.m270.l1313The motivation was to attempt to address a knock I was concerned about, which from what I have read may have been due to a rough idle and rough acceleration until beyond 3,000 RPM. Initially I was thinking of sending the originals off for cleaning, and it was not much more money to purchase the rebuilt upgrades.
Immediately on startup after the installation the idle was noticeably smoother. At operating temperature the idle is now 1,200 rpm versus 1,000 before. And where previously the bike smoothed out over 3,000 rpm, it is now smooth at all rpms. I was cruising through a parking lot in 1st at 1200rpm, completely smooth. I cruised in 4th gear in city traffic on a slight incline at 2,000 rpm, completely smooth, though power loaded.
DISCLAIMER: YMMV. I have owned this bike, my only K bike, for all of 400 miles. While I recommend this upgrade, I also think one of the original injectors on this bike may have some issues. The electrical connector for the injector on the #1 cylinder was slightly discolored, and in general the area around that injector looked like it may have experienced some over heating or a small fire or something at one point in the past. And, the grommet for the fuel rail mount in that location was seriously degraded compared to the one by cylinder #3. In any event it's possible some occurrence negatively affected that injector. Or maybe they did just need cleaning. I do know the rebuilt injectors are a significant improvement all by themselves, and the knock that had me concerned at idle is gone.
