Been noticing lately that when I switch into a gear and if I try giving it alot of gas it has a hard time picking up speed unless I fully let off the throttle and give it gas again. Would that be a fuel pump issue?

 

I've got what seems like the exact same problem going on. For me, it seems to be better some days and worse on others. My bike will rev fine up to about 4k and then it sputters up until about 6k where it picks up again.

You're not alone, it seems to be some sort of air/fuel related problem. I'm trying to research what could be wrong as well.

 

Hey Fellas,

It could be a fuel pump, but I doubt it. The fuel pump in these bikes was an added "bonus" from the traditional fuel delivery of the F1 and F2 models. The idea is that when you reach higher speeds (around 85mph or so) or when you're in tight lean the pump will supplement the fuel system to keep go-go juice flowing to your motor.

That being said, it is unlikely that it would cut out at the revs you guys are talking about because I wouldn't think the pump would really being throwing fuel that hard. I could be totally off base here, but if my logic is correct...

Depending on your mechanical knowledge (and time and patience levels) you may want to start with your carbs. If they haven't been cleaned in awhile you can kill two birds with one stone. Grab a shop manual and check the How-to below. This will give you a chance to check for debris, make sure flow hoses are attached correctly, and look for any broken pieces. I can't promise this is your fix, but a problem in your carbs would be my first check.
https://cbrforum.com/forum/showthrea...=carb+cleaning

Good Luck and keep us posted with your bikes.

Steve

 

-first off, let me start off by saying I purchased this bike last weekend from someone who hardly ever rode it since he bought it years ago. He took it in to get regular maintenance but pretty much only used it for short distance trips and probably only started and ran it once a month. My presumption is that the bike might just be bogging because of dirty carbs, but it could be incorrect jetting.

Ok so I spent about 5 hours today taking the bike apart down to the carbs, cleaning them, rebuilding them, and then putting everything back together. When I took the bike apart, I also made sure that all the whole ridiculous air routing circuit was correct.

So here's what I know after reassembling everything.

-The carbs were dirty, but not nearly as much as I previously thought. Only a small amount of build up from the bike sitting around

-The slow air routing circuit might have had something blocking it, but it definitely doesn't now. I cleaned out all the lines and reassembled everything properly.

-When I took the carbs apart, I was looking at a 40 pilot jet and a 132.5 main jet.

-The solenoid for the air routing system DOES work. I can hear it popping into position when I turn the key to run.

-The fuel pump should be working. I've gotten up to 105 on the bike, and it freely revs up to the redline once it gets past its bog-down point.

 

...So basically do I just have the wrong jets in this bike or what? I forgot to mention that it has a two brothers slip on as well as a K&N air filter... two things that can definitely throw off the air/fuel ratio.

The problem I'm having right now though is that the bike seems as though it's running too rich. I haven't checked the plugs yet (don't know how to yet either on this bike b/c I'm used to suzukis). It's still bogging down but only if you wail on the throttle. The problem seems to occur between 3k and 5k the most. I'd think that if it weren't getting enough air, then it would die on the upper end, but that seems to be where it's running the best.

So what's the deal here???

 

I'm having the exact same issue.