Bogging, Wont rev

Ok Guys im having problems with my 82 csr 750. It was a barn find. Last time is it was plated was in 87. Anyways I have read every form out there over this topic. I have rebuilt the carbs, soaked them in carb cleaner over night, blew them out the whole 9 yards. I put them back on and still same problems. I have stock air box on it as of now. will not rev up. idles fine. if you give it the slightest throttle it will rev up to about 1200 rpm if that. give it anymore just bogs down. the only thing I have done different is take the vacuum cockpit of and put a gravity feed one on. if you spray starting fluid in the air box it will rev up. I have clear fuel hose on it and see fuel flowing. Just need a direction to go. Thanks

I would check the ignition advancer. If it is sticking it can cause the symptoms you describe. Clean and lube it to make sure it operates freely. Ed

Ok. Well do you think that even though you can spray starring fluod in it and it revs all the way up?

I don't know. It's possible that the starting fluid is more volatile and makes the engine rev higher. I any case, if you haven't cleaned and lubed the advancer in recent memory it wouldn't hurt to do so and ensure it's operating freely. Ed

Ok I will clean it and see what happeneds. If yoy have any other ideas just let me know.

I'd take the fuel tank cap off, and dis-assemble it, making sure the vent is open. Usually screws hold it together.

I have ran it with the cap off didnt make a difference. I didnt have time to mess with it lastnight. Tonight I should have time and see what I can find. Ill still make sure the vent is working.

Ok well the advancer moves freely and the vent is working good on the tank. I dont know what else to do guys. Im about ready to take it to the shop but really dont want to.

How's the compression? A new/rebuilt engine may have 180 or more PSI, get some years & miles on it, and maybe 165 or so. An engine will run at 100 PSI, but produce low power & burn gas. There should not be more than 10% between cylinders for a smooth running engine.

Do you have a shop manual? If not, look at these websites:
Manuals (Some of these websites sell used manuals, just ask)
www.repairmanual.com
www.manualsnmore.com
www.midwestmanuals.com/
www.books4cars.com/
www.repairmanualclub.com/motomanuals/
moto-manuals.com/
www.e-classicbike.com/
www.repairthatmotorcycle.com/manuals/kawasaki.html
www.manualedereparatie.info/en/categorii/kawasaki.html

And:
mbsween.bike-night.com/kz750l3/manual.html

Can be your carbs are still dirty even after all the cleaning you did, I had to clean mine more than a few times before they ran right, make sure you have a fuel filter, and ask Patton to show you the diagram which shows you how to properly spray carb cleaner after a good soaking, a member here recommended soaking the carburetors in diesel fuel, and that is what finally got them clean, after trying all kinds of cleaning solutions.

Since the bike has been sitting a while, how clean is the tank? Is there a bunch of rust around the screen of the petcock and not allowing enough gas through? Does that bike have bowl vents on the carbs? If it can't get enough fuel in the carbs, it's going to stave. And sometimes it takes multiple carb cleaning to get all the junk out. Good luck.

CoreyFord wrote: ... 82 csr 750... will not rev up. idles fine. if you give it the slightest throttle it will rev up to about 1200 rpm if that. give it anymore just bogs down... if you spray starting fluid in the air box it will rev up. I have clear fuel hose on it and see fuel flowing. Just need a direction to go....

if you spray starting fluid in the air box it will rev up -- imo, would indicate that the carb pilot circuit is not yet perfectly clean.

If needed, this link enables downloading a 1982 KZ750 twin manual, which I believe (but am not positive) is same as the carb at hand.

bublicpucket.s3.amazonaws.com/Manuals/ka...llwith80and81sup.pdf

Here's an excerpt from page 133 that addresses the carb pilot circuit:










Would spray pressurized carb cleaner through the pilot passages until the spray squirts through the orifices into the carb bore, and keep spraying until certain that both orifices are perfectly clean and clear.


Good Fortune!