I'm having an issue with WOT bogging on my 89 GSXR1100, but it's only when it's under load, it revs perfectly in neutral. It will rev pretty well until it hits about 6K, then it starts to hesitate and won't go past 7K. I thoroughly cleaned the carbs to see if it would help, and it didn't do anything. Anyone on here have any ideas?
WOT Bog
- Thread starter YSR89
- Start date
hayabusafiend
boxing twins
Before you dive into jetting (and taking off the carbs again), when were the spark plugs and air filter replaced?
The kit was installed about 2 years ago, it's a Dynojet stage 3 kit that I got with the pipe. It ran through the RPMs fine last summer, just now it's giving me problems. I'll pick up a set of plugs for it to see if it helps. The thing that confused me was that it is only an issue under load and not neutral.
Whoops, I missed that question, my bad. It doesn't get through the bog, it just bogs. I dropped the clip, but it made the bog worse (would idle but not rev at all.) So I'm going to lean it out. I was running the clip right in the middle, but I'm running a DJ160 main, which is pretty big, so it may just need to be leaned out a little. I'm going to pull off the carbs and try it in the morning, I'll keep you guys posted on how things work out.
rapidrobbie
Ride Fast Take Chances
First off throw the dynojunk kit in the trash where it belongs.their needle shape/taper is horrible and their jet size #s are meaningless,and I believe they either cut the slide springs or use different ones. Use mikuni stuff.Are the emulsion tubes(where the needle goes)oval?probably yes on this bike.stock airbox?What are the float heights set at?very critical on the mikuni cvs,should be at 15-16mm with carbs inverted.
Last edited:
Well, I leaned out the needle one position (now at second from top) At this point, it's misting gas out of the back of the carbs, and when moving there is the same midrange bog except when the throttle is held open, after a little bog it takes off like a rocketship, but due to the way it's running in the bottom end, it's almost unrideable.
I did lean out the main, I installed a 124 main jet, but it's running too lean with it, even with the clip on the bottom position it is backfiring with throttle and bogging unless throttle is applied gradually. The springs do not appear to be cut, and the float level is fine. It stopped spraying fuel when the 124 jets were installed, but it's still not running right. Maybe a 150 or 155 jet would be better?
hayabusafiend
boxing twins
Did you replace the plugs and air filter first? I'm a bit puzzled. "Fine last summer" and "It's always been like this". Which is it? How was it last week? Last month? Was it a progressive or sudden decline in performance?
A sudden decline in performance isn't usually caused by jetting. I think you're chasing your tail.
A sudden decline in performance isn't usually caused by jetting. I think you're chasing your tail.
Last edited:
I worded it a little weird, it wasn't FINE last summer, it had this same issue, although it wasn't as bad. I think maybe my needle jets are worn so they're not performing right, since the issue is in the needle jet's throttle zone (1/2 to 3/4 throttle.) I changed the plugs and the air filters are new.