Join Date: May 2018
Thanked 21 Times in 21 Posts
Everything from the tune/mis-tune to the air filter could cause a loss in power. Injectors being gunked up, lower quality fuel, natural engine wear, cat converter being faulty, etc...so many things which wouldn't outright throw a code. If you could check compression and do service tests on sensors and other devices that would rule out a ton of stuff, all stuff you can do with just checking data from the ECU. If you have a code then the code is probably the source of any problems, though there could be others conceivably. Specific to the 675 there's nothing I can think of worth mentioning.
If your EXUP is deleted you'll have much less low-end torque, it moves it higher in the rev range is all. It might make more HP up top as well, but down low it turns it into a bit of a prissy little Nancy. With the EXUP it's not exactly gobs of TQ, but it's enough to be useful for putting around town. Compared to a Gixxer1000 it should be able to reasonably keep up from 30-100 mph, but it depends on gearing I suppose. It's really more about power to weight than outright power, but the Suzuki should still certainly be more beastly all around.