Hey guys.. Finally wanted to see what the f4 can do on the highway.. and was not impressed. It hesitates horribly, i had to fight to get it up to 80 mph.. it wouldn't break 90 if my life depended on it. That's dropping 2-3 gears as well.. What could make the bike run pristine at lower speeds and hesitate at higher speeds? The carbs are freshly cleaned.. Any ideas??

 

Does it lose power or sound like its getting too much gas or not enough? Is this the first time you have had it out since winter? When was the last time you checked your plugs?

 

Honestly, I can't tell if this is a rich/lean condition because of the wind noise.. I was trying to tuck down and listen.. but I can NOT get a good idea. I'm an auto tech so I know what to listen for but I just couldn't distinguish. This is not the first time, I just bought the bike, it didn't run right .. did a carb cleaning and it ran mint. I've had her on the highway a few times but never over 65. I have not checked plugs.. i'll pull one in the am and report back here.

 

Yeah the spacing may be off or they may be dirty... Not the easiest thing to check but hopefully something minor like that!

 

If I may suggest, try checking all of your vacuum hoses, sounds like a staging problem. Also check your Direct Air Induction System, that's the one that has the Air Selonoid Valve, If the vavle has failed (12v trigger @ 20MPH) you won't have enough pressure in your float bowls.

 

Also, when you cleaned your carbs, did you remove your Throttle Position Sensor? Hope not.

 

when you said that you haven't had it past 65, are you going all the way through the rpm's when your shifting in the low gears? that should tell you if its carb problems. my guess would be that its lean?? put it in neutral and just wop that throttle w.f.o. my buddy has a katana that wont get past around 100. but then again it wont rev out either cause its WAY to lean on top end. if you have to, pull your carbs and check what size your main jets are. my jets are 124 for #1 and 4 and 126 for #2 and 3 and my elevation is around 900ft.

 

another thing to check. Does it just fall flat on its face? Mine did this and the fuel line was pinched between the bottom of the tank and the frame where the tank mounts

 

Nice, a rush of ideas to get me thinking. No, I did not remove the tps. The bike will rev to WOT all day long and off highway it will rip through gears to redline with NO hesitation. It doesn't quite fall flat on it's face, it just won't really rev any higher. Roll on in 6th.. no go. Downshift to 5th.. no go.. one more to 4th.. hardly anything. I guess I need to read up on how to check those air valves eh? I am going to pull the tank today and re-check hoses and pull a plug for the hell of it. It was raining out yesterday. Thanks for input this is great.

 

I am experiencing the same thing with a newly acquired F4 with 80,000km. I was wondering if there was an resolution to this issue?