Throttle issues.

So ive been fighting this issue for a few months.
I have a 1980 Kawasaki kz650 LTD
Bone stock minus the exhaust being cut off due to the stock ones being clogged.

It starts up fine and has a good idel with a little choke till its nice and warm. Though it will randomly rev up to around 3-5 grand and hang there until i use less choke.
Also im haveing an issue with the throttle bogging jt down to the point the bike dies.
If i let it warm up and i try to ride it it wont rev past about 2 grand.
Any ideas???

Fairly new to the bike still learning it. I have a feeling it may have part to do with not having the proper back pressure.

The carbs have been completely refurbished and the values have been adjusted back to stock.

It needs mufflers to run correctly.

baldy110 is absolutely correct. Without a proper exhaust system the engine will not run right. Ed

Rising revs when warming up on the choke are normal. But I wouldn't let it rev up to 5 grand. No need for that high a rev.

Sounds like your bike is bogging out when you try to put power to the back wheel. I don't think your exhaust setup would cause the bike to bog out but it's a good idea to replace it with something.

Some things to check...

1) is the compression OK? - could be a bad engine.
2) does the gear shift work correctly? - could be in a high gear
3) are all 4 pipes heating up? - could be a coil is gone or maybe one cylinder is not getting proper spark.

If he's running straight pipes then yes it will cause a big bog and the sad part is you cannot tune it out. Exhaust changes cause more carb issues than intake changes.

in my experience, intake changes require more drastic jetting changes than exhaust. Some exhaust changes don't require any jetting changes. I've tuned bikes to run fine without any muffler, but that does require some major jetting changes.

In my experience I agree with Lou, intake changes require more carb work than exhaust. But have to add that I have not ever tried to tune a bike with straight pipes. Cars yes but not bikes.

My experience is if you keep the stock exhaust and replace the stock air filter assembly with pod filters no jetting change is needed. Now keep the stock air cleaner assembly and swap in a good 4-1 pipe it now requires jetting changes and tuning.

That's interesting. I found the exact opposite on one of the Kz400 I'm working on. With no mufflers, the bike ran ok, not perfect but drivable. Without an airbox it really wouldn't even start. Same with other CV carb bikes I've worked on.

On the Gpz550's a Kerker 4-into 1 runs fine with stock jets even though warmup takes longer, that is, you have to keep the choke on longer.
Going to pods means all sorts of hesitation on the gpz 550.

Most people usually swap to pods and exhaust at the same time so when they try to tune for the changes they are playing with the carbs. So they assume the intake system is to blame for the required changes. Now mix CV carbs with straight pipes and it will never be tuned properly. People can get them to run ok but it's not correct they will always have problems somewhere in the throttle settings.

From a technical perspective an exhaust system is designed to ensure the negative half of the returning pressure wave arrives just as the exhaust valve opens. This creates a negative pressure to help suck exhaust gas out into the exhaust pipe. Without it the engine exhaust has to overcome higher resistance and therefore will not operate as efficiently. But it will operate.

Other than that the main purpose of an exhaust system is to reduce the sound waves to a reasonable level.

I ran pods on a Kz400 with CV carbs and a modified exhaust and it ran perfectly. There were no problems in any throttle positions. It ran as good if not better than a stock system. The jetting involved air jets and fuel jets and was not simple, but it was certainly not impossible. I'm not saying all CV carbs can go with pods, but the few I've dealt with so far have been successful. I wouldn't recommend that for beginners, though. It takes months of patience and testing.