No low end, everything else... pretty good

Let me start off by saying KZR people, you are the best! I would not be even where I am now without this community.

So, I have synched the carbs and the bike idles fairly nice with no choke (once warm), but I have absolutely no low end in first gear. I almost have to get it rolling first otherwise it dies. Once I am rolling the thing feels great in all gears. Any thoughts?

Do you have the stock air box and filter? Are you positive the bike is running on all 4 cylinders? Ed

I have pods, no air box came with the bike. Hmm, I will check to make sure I am running on all cylinders tomorrow. Being that it runs really well once rolling, I just assumed it was running on all four. I know it WAS running on all four, however, I have since coupled one of the spark plug wired as it was about an inch too short.

Weak spark? Blue or yellow?
Steve

I just went through this problem with my carbs.
I suggest you get all new O-Ring ,gaskets and the proper Pilet jet in it.. Any little air leak will effect ideal up to 3500rpm.
Above 3500rpm their is enough vacuum from the motor...that's why your bike runs better.

Badly out of synch carbs can cause this - did you synch with vacuum guages and the motor running? (as opposed to bench synch where you are just getting the throttles to open exactly the same together)

Are your vacuum take offs on the carb manifolds blanked, and the vac fuel tap line correct?

You could try linking these vacuum takes off, 1 and 4 and 2 and 3 and run the fuel tap on prime. any instant improvement noticed by doing this is indicative of a carb balance issue.

Also I'd replace ignition HT leads and plug caps as a matter of course on any old bike, also clean up/replace the coil LT connectors under the fuel tank get manky and can cause problems.

Did you do anything with the cams? Might be one tooth off. It happens.
Steve

Didn't get an answer to the spark question.
Steve

The spark is strong and the bike is running on all 4. I have rebuilt the carbs and I changed out the exhaust to a 4-into-1 ( dont know if back pressure matters). I used the jets that came with the rebuild kit. I replaced the vacuum lines between the carbs, but I am not sure where else I would be getting vacuum leak, if that is the case. The boots appear to be supple, not cracked and in pretty good condition. Not that I know of a way to check if they are good or not. Perhaps I could replace the vacuum line with a smaller internal diameter to ensure there is no leak. It was suggested that I might need to rejet the carbs, dont know if that would help.

Are the RPMs going up but nothing to show for it, or is it just bogging down?
If it's the former could be the clutches.

ewolpert wrote: The spark is strong and the bike is running on all 4. I have rebuilt the carbs and I changed out the exhaust to a 4-into-1 ( dont know if back pressure matters). I used the jets that came with the rebuild kit. I replaced the vacuum lines between the carbs, but I am not sure where else I would be getting vacuum leak, if that is the case. The boots appear to be supple, not cracked and in pretty good condition. Not that I know of a way to check if they are good or not. Perhaps I could replace the vacuum line with a smaller internal diameter to ensure there is no leak. It was suggested that I might need to rejet the carbs, dont know if that would help.

That might be the problem. There are NO vacuum lines between the carbs. You may want to post a picture of what you have done since it sounds like you have made a mistake in the routing of some tubing. If you show us what you have done we may be able to help sort it out. Ed

I think the 3 carbs are blanked off at the intake manifold spiggot and a 4 th is piped to the vacuum fuel tap.

linking the intakes works like a crossover manifold in reverse, but limited in the bore size therefore only really makes a noticeable difference if the carbs are badly out of balance in my experience, hence my suggestion as a diagnostic to reduce that possible out of balance question.

Changed the jets? If you a running pods and a 4-1 you need to go up probably one main jet size and a needle height adjustment, as a minimum plus tuning the pilot jet airscrews. Your off the throttle response is your pilot and primary jets only i think, you might just have got lucky and the main jet and needle choice and height is ok and it runs great apart from this. Tuning top down,

The kz gpz seem quite cold blooded, 550's in particular . they race when cold on full choke and it needs a mile just to warm enough to pull cleanly off the throttle.