Topic: CB750K7 slight interruption of power supply around 7-8 RPM

[olasek18_18@o2.pl]

Hi, I'm having trouble getting full power at higher RPM.
Everything has already been done on the motorcycle - a complete rebuild cylinder head, ignition timing, cleaned and synchronized carburetors.

The motorcycle has serial 110 air main jet and original Airbox,
 exhaust is kerker, could it be a problem to get full power?

I feel a slight burst of power around 7-8 RPM, I think the spark plugs are the right color, maybe they are little too dry ...

Any suggestions?

[olasek18_18@o2.pl]

the bike:

[rotortiller]

While I have no idea if a power loss spike is the problem, these bikes have problem connections in the ignition switch. The riveted terminal lugs get loose and/or corroded. The switch can be taken apart at the area in question, cleaned and soldered should that be the snag. Check kill switch also as it comes apart too.

[olasek18_18@o2.pl]

Another thing came to my mind, quite trivial I think, maybe the fuel tap or filter is clogged and has a restricted fuel supply ...

[Jerry Rxman Griffin aka MuthaF'er]

If your plugs are a little too dry raise the needle one notch or increase your main jet to 115. It just depends on the rpm range(s) your plugs are dry. I will assume that the air filter is unrestricted.

[BenelliSEI]

Your pipes look like they are getting pretty hot, so I agree you maybe a bit lean. Also, remove your fuse box and look in the back(pop the back cover off). The main lead (15 amp fuse) gets very hot. It melts the plastic away from the fuse clips, making a poor connection. At certain revs, you may actually be getting a vibration that breaks contact for a millisecond. Just like a breakdown in the key switch, hard to detect. If the box is visibly melted, change it out. A cheap fix is to move the clips to the two unused spaces (currently your “spare” fuse spaces).