Need help - about to give up

I have been through this bike (1982 KZ750 Twin CSR) and repaired or replaced and I can not get it to run right. I am ready to give up and sale it for what I can get.

It runs with the choke off but will not stay running for more than a couple of minutes. Even after soaking the carbs for 24 hours in 50% solution of pinsol then blowing out with carb cleaner. I replaced the oring for the pilot jet screw, enrichment circuit, and the rubber plug for the pilot jet was replaced. The tank has been cleaned and sealed. the carb holders are new, the rubber boots for the airbox to the carbs are new (sorry i do know what they are called). New spark plugs and air cleaner. There is a fuel filter inline for the carbs. Originally when I purchased the bike it has BS38 carbs on it so I replaced them with BS34 carbs, these are the ones that were cleaned and all the parts replaced. I have the timing governor cleaned, lubed, and reinstalled. Bike is still hard to start, idles rough, sluggish rev and only goes to 4500 rpm at WOT.
What am I missing? Would old diaphragms cause this (they were soaked in alcohol with wintergreen overnight and I could not find any holes) or how do I tell if the slides are opening properly?
Please any advice on where to start.

Carbs still dirty is what I'd guess.

This rebuild guide shows carbs that are a little different than yours, but reading through should help you understand what it takes to properly clean a set of carbs...
zeus.mtsac.edu/~cliff/storage/gs/Mikuni_...Rebuild_Tutorial.pdf

That is the guide I used to go through the carbs. I am trying to find out if the symptoms are carb related or if I need to look elsewhere.

Did you ungang the carbs fully, remove the pilot screws, pilot jets, everything? Check the choke pick up tube? Check the choke passage in the float bowl? I'm not sure pinesole cleans all that well also. Carb dip is better.

I unganged the carbs and removed all of that. I was trying to be as through as possible. The pinsol worked alot better than I thought. I had a hard time finding the carb dip locally. I tried to verify every passage was clear by using aerosol carb cleaner to blow through them all and make sure everything was cleared out. If this seems to be symptoms of a carb problem then I will.start with that . I was just wanting some advice to get an idea as to what would cause this type of problems.

Valves adjusted?
Steve

No the valves have not been adjusted. I will look that up in the FSM tonight and put that on top of the to do list. What are the symptoms of valve out of adjustment? Just so I know.

As of a few years ago pinesol no longer contains pine oil, so it probably doesn't work as good as some of the old how-tos claim. For a pine cleaner I would use Pine-o-pine as it has about 30% pine oil. more than pinesol ever had. Or Nice! pine cleaner which is probably the same as old pinesol. Pine oil is supposed to be a good solvent.
I use the Berryman's original formula parts cleaner (NLA). Berryman's professional carb/parts cleaner available nowadays is similar.

Other stuff. Is the stock airbox & airbox cap properly installed with a good stock type air filter?

You can use 7mm copper core spark plug wire from the auto parts store. I guess you can reuse the o-rings & stuff from the old plug wires. If need be for a better fit, the outer sheathing on the stock plug wires can be removed & used on the new wires (credit to Nessism). I would use Liquid wrench silicone spray lubricant to remove the sheathing.

New inexpensive stock type coils for electronic ignition are available on eebbaayy. loudhvx has mentioned them in a recent topic. Some of them include the spark plug wires.

ric812 wrote: No the valves have not been adjusted. I will look that up in the FSM tonight and put that on top of the to do list. What are the symptoms of valve out of adjustment? Just so I know.

While you're at it you might want to find the maintenance schedule in the FSM and make a plan to bring everything up to date. It's extremely difficult to diagnose running problems on a bike where the basic maintenance is not done.

A lot of times a bike will be sold with the carbs "needing to be cleaned" only to find the valves were neglected to the point it wouldn't run anymore. No amount of carb work will correct that. Do the basics then go to the carbs if needed.
Steve

Nessism wrote:

ric812 wrote: No the valves have not been adjusted. I will look that up in the FSM tonight and put that on top of the to do list. What are the symptoms of valve out of adjustment? Just so I know.

While you're at it you might want to find the maintenance schedule in the FSM and make a plan to bring everything up to date. It's extremely difficult to diagnose running problems on a bike where the basic maintenance is not done.

+!


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Ok I will bring the maintenance up to date this weekend. The airbox ducts, carb holders, coils, plug wire , plugs are all new.
I am sorry i should have thought about going through the basic maintenance before asking. I just got really frustrated and wasn't thinking.