1994 K75S w/ABS (Red)
72,021 odometer
I believe I've solved an issue that's been nagging me for months. I first noticed the issue on my 40 min commute to work. After riding for 15-20min or so the bike would start choking and even dropping the rpms all the way down when I was around 5,000 to 5,500 rpms especially. I can ride it for a long time at rpms lower than that, but it's more fun riding it at the higher rpms. It also got worse and worse with backfiring as I decelerate and shift down gears *pop pop pop*. Instead of posting here I've just been searching this forum with the help of google to find any post related to my issue. Also Chat GPT was super helpful with advice on troubleshooting this issue as well.
I live close to a local K Bike expert here in North Alabama (John Zeiler), and he recommended I send my injectors to Mr. Injector. I just got them back today, and after installing them, the bike runs like a dream! According to Bill, 2 of the injectors had no spray at all, and 1 of them had low spray. He was able to get all three to 100%. I don't think I've ever experienced the smoothness of a K75 until today. Everyone said they were smooth bikes, but I just found that my 1999 K1200LT was much more smooth.
In addition to getting the injectors cleaned, I:
- Replaced all the fuel injection hoses (got mine at a local auto parts store, but they were $1 per inch! Yikes.)
- Replaced the famous "Z" crankcase breather hose ($9.95 from Beemer Boneyard)
- Replaced the vacuum hose ($5.99 from EuroMotoElectrics P/N 11 72 7 545 323)
- Replaced the two vacuum caps ($1.50ea from EuroMotoElectrics P/N 13 54 7 694 924)
- Cleaned the 4-pin tank plug with electronics cleaner and deoxit
- Cleaned the electrical injector plugs same way
I hope this post helps others as they diagnose their issues. I'm taking this bike to work tomorrow to continue to test it especially while it's warm. I really hope that the choking problem is completely solved. If it isn't I will look into the valve clearance, the coils, and whatever else may be related.
