Flatspot in 5th and 6th gear..?

[heretic]

Holy Flatspot..!!  Where's the torque..?

Well, my b4 is back from the mechanic after the voltage rectifier woes, but, riding it about town, I thought about some of the other symptoms I came across.

Since this is my first bike, I havent been letting her rip as much as I would like to/is possible.  So she's been very rarely over 8k rpm.

In 1st to 4th gears, she revs through to 11000 rpm easily with no  gaps..  however in 5th or 6th, as I come to 6000 rpm, it struggles to go up, I mean, it takes about 30 seconds to a minute to go up every 1000rpm.

Is this the oft heard about "flat spot"..?  I dont know if it ever bottoms out, I never had the time to keep gunning the engine waiting for it to reach a point when it puts out more power.  I usually down shift into 4th, rev up to 11000 rpm instead and then back into 5th which takes me to about 9000rpm.  From there it doesnt seem to have a problem.

Is this normal..?

Another quick question..?  What rpm does your bike idle at..?  I've got a screw on the side that increases/decreases the idling rpm, and mine is usually at 1k or 1.5k  Is this a high amount or ok..?

[PitterB4]

Well, being a mechanical doofus, I will leave the reasons to the more technically gifted but I will say that you 5th/6th gear issue is not normal.  The "flatspot" I have is in all gears at around 4-5k when it's cold out.  It only takes a second or two to rev through it and gets better as the bike warms up.  

As for the idle, I forget what its supposed to be.  I would strongly recommend that you get your hands on a manual.  That and a thousand other things are covered there.  There's almost always one on ebay or you can download it from echomadman in the stickied thread in this forum.

Good luck.

[gunter]

I would check the carbs.

I had similar issues with my bike last summer, but I pulled the carbs and did a complete tear down and rebuild. I also found the previous owner installed bigger aftermarket jets that were causing rich conditions at higher rpm's.
Try doing a good carb cleaning, followed by synchronizing them.

Good luck.