I bought the 4-hole reman. Bosch fuel injectors off Ebay for $100 from Oside Tiger outfit. My bike had 31k on it, and I thought why not, after reading up on the 4-hole vs. single pintle style of injector our bikes are equipped with. I have recently replaced throttle body bushings, fuel lines, fuel filter, vacuum lines etc., and sync'd the throttle bodies.
These are BMW 318i O.E. injectors, and Oside Tiger stated they were 'plug-n-play' in the K1100...and they seem to be...so that's a plus.
1st start-up: bike ran fine, injectors worked with no issues/leaks....good news, it runs!
After 30 mile ride: bike ran well, but...but I didn't feel any huge improvement in performance. The engine did seem a tad bit more responsive, it reached higher rpm's quicker/easier with maybe less throttle opening??...it was hard to tell any big change...which is probably good in ways. (Next Day)After another 20 mile ride, the bike is running very well, and it does seem to be...quicker...
If your bike has high mileage or dirty injectors, these may be a good option. With 31k on my O.E. injectors i didn't really see huge difference, but they certainly work well. Maybe mileage will improve but I don't really care about that per se...I just wanted to try them.
The theory and info online of 4-hole vs. single, seems to make sense --better atomization/vaporization and thus, more efficient-- maybe I just don't have the sense to feel how much better they are...
P.S. After 1200+ mile trip to Black Hills, the bike ran superb...for $100, these appear to be a worthy upgrade.