i_VTEC

My bike (93 CBR F2) recently had a new head gasket installed and had the carbs cleaned and tuned. Valves were checked to make sure there was no tight valve. You name it, It was done. The one thing that no one can seem to fix is the problem I have while riding on the highway. My bike seems to surge (Slow and go) almost like it is not getting fuel for a second then gets it. Ive had this problem ever since I bought the bike. Has anyone ever had this problem or does anyone know how to fix it?

Starscream

Have you checked the regulator/rectifier and the electrical system? Grab yourself a voltimeter and check the outputs...there should be plenty of guides in the net of how to do the process.

It's late, but if tomorrow nobody has posted them, I will try finding a couple guides for you.

My bike used to have a similar problem when riding on the highway, it would rev, then stutter for a while, and then pickup again. It was the R/R. Pretty common item to be replaced on Hondas, more so on a bike with the vintage like a F2.

i_VTEC

You know I was actually beginning to think that it might be an electrical problem instead of a carburetor problem... I do however have a K&N air filter on stock exhaust and jetting as he put it... " Changed jetting to # 40 jets, 147.5 main jets, needles dropped all the way down. Stock air box. Intake snorkel is slightly opened at the tips" That is what he wrote in the write up. Could it be that I might be getting too much air into my motor?

As far as Rectifiers go, I heard of people purchasing aftermarket ones... Any input on aftermarket over OEM?

kramer778

surging is usually caused by improper fuel level . They may not have checked the float height when the carbs were done. Check your plugs for proper color.
White = lean
Black = rich

i_VTEC

He checked to make sure it was not running too rich or lean. It's either electrical or fuel delivery. It's seems like its only on the highway, Not in the city. i could be doing 65 in the city and it doesn't do it, But if I'm doing 65 on the highway. It surges and bogs but after a few seconds it will pick up... Any possibility that it might be too much air though?

kramer778

too much air? not enough fuel. The needles control your mid range and from the looks of it he has them as lean as it can go . I have never had to have neddles all the way lean ,even with a good exaust and individual air filters. I would say the jetting is way off. Electrical, 99% of the time it works or it don't.Get theneedles lifted to about the middle position and you should be close

MSchu

Can you explain this better? surging is acceleration, Bogging is deceleration

i_VTEC

Sorry. Let me try and explain this in detail.. As I am hopping on the freeway gradually changing gears at about 7,000 RPMS, I eventually get to 6th gear doing about 70 MPH. While holding the throttle steady The bike will maintain 70 then suddenly lose power and decelerate, Then accelerate back to 70. It feels like a rocking back and forth movement. When the bike decelerates, I will give it more throttle and it bogs for a second or two then just picks up quick because at that point I have about 3/4 throttle open. Or I can simply lower gear and keep it at higher RPM's. It almost feels as if there is a flat spot at about 6-7500 RPMS. I hope this helps a bit more...

MSchu

Okay.. sounds like two things you should check to rule out. one would be your coil pack... it may be starting to go bad and ignite intermittently.
the second more probable cause might be that your diaphragms in your CV carbs have a hole in them somewhere. this would cause a momentary drop in the slide in one or more of the carb bodies. before catching and rising again. I mention the carb issue because it won't cost you any money to check that. the other you have to replace the pack or packs to find out if that was the cause.

While I don't have or have had a f2, I have seen this on other bikes with CV type carbs

i_VTEC

Now I'm still a newbie but coil packs are what send the spark through the spark plug wires right? If so there are two... How would I know which one? If I'm even on the right track here.... I can almost be certain that there is no hole because the mechanic checked and did not mention anything out of the ordinary. So like I mentioned before... This might be an "electrical" problem. =/

kramer778

Take them in and have them tested

MSchu

yes the coils/ignitor generate and send the spark to the plugs... but something else signals the coils to generate the spark.

personally, i think it is fuel related not electrical in nature because you do not loose all power, you only loose partial power and is comes back on. That is, unless its only on half the cylinder banks.

FYI, make sure those guys that worked on you bike actually dissembled the carb bodies to check the diaphragm. I would be willing to bet that most places don't actually do that

kramer778

You may have a fuel filter that is getting clogged or a pump that is going bad. Check the tank vent also

bar10dah

Could be way off base, but I had an '89 600F that would seem to lose power on the highway like you described. Found the problem to be a partially pinched vacuum tube coming out of the bottom of the tank. Could be worth looking into.

kramer778

That would be the tank vent

MSchu

definitely, a pinched breather can induce that symptom

bar10dah

Yes, and it was causing a vacuum in the tank and not letting the appropriate amount of fuel into the carb float bowls under high acceleration and/or RPM. It may not be the solution to the original post, but it's worth a look.

Jasper_db1

*should have sold it to jasper*

i_VTEC

That's the only reason why I still think it can be fuel related. It only happens at higher RPM's and speeds. Should I check if it may be a rich or lean problem? Like the cold motor/hot motor method?

kramer778

The most accurate way is to read the plugs. If you don't want to take things apart,you can try riding it with the gas cap loose to see if it is a vent problem.Do this with the tank 1/2 full or less to prevent spillage.If it runs fine then the vent hose is kinked,if not there is another problem.

i_VTEC

Ill try that tomorrow and let you know how it works out!

jayd4

Hi I have a 1992 honda cbr 600 and i got everything check like the fuel system carbs got cleaned check fuel filter and lines changed oil spark plugs and wires changed gas put seafoam in but still boggs i dont realy understand it it doesnt do it all the time but when it does it feels like it's not getting enough fuel then when i roll the throttle it shuts off then i have probs starting it. can some 1 help i would apreciate it. because this is my first bike and i dont know how to ride that well and the only way to learn is to just jump on but i wont when it acts like that.

thank for the help to whoever helps

eliciamae

I am having a similer problem. My 81 CB650 starts choking at 5rpms. Carbs have been thoroughly cleaned. Nothing electrical. Cleaned the gas tank. And have done everything elae we could think of. We did notice the needles were different sizes and we are unable to adjust the needles. ..any thought?

slomofo

iTrader: (1)

Different needles? Did you cross reference the numbers on the needles to see what they were meant for? How big of a difference?

On the needles that are bigger, you can try this if you want, it's kinda time consuming but it might work. Try getting tiny washers and shimming the needles just a little bit so that they pull out of the jets allowing more fuel in. If that helps, then pull all the needles out and get the proper size.