1981 KZ750 running problems.

Two days ago, I was riding the bike up and down the streets. 1 day ago, cold spell, i tried to start the bike regardless (very cold blooded) so of course it didnt work, i ended up killing the battery, no surprise there.

well today, i bump started it, it caught. pulled the choke up to get the engine hot. 10 minutes later, the engine never pitched up, so i assumed it was warm regardless. I tried riding the bike.

Here's where the problem lies. First gear is fine, i can give it throttle and it will accelerate. but once i shift into second, if i give it more than the bare minimum of throttle the engine doesnt respond. i have no clue why its doing this.

but the engine reacts to the throttle when im riding downhill. up hill, nothing.

Thanks for your help.

I think all of the 750's are cold-blooded, mines the same way. One way I've help overcome it is to prime the carbs before a cold start....

What carbs do you have? If you have CV34's, your symptoms are similiar to a problem I had with my 400 where the carb diaphram was torn. When I hit the throttle the engine would bog down, but it was better in downhill situations.

Im not sure what kind of carburetors it has, but one thing that i probably should have mentioned is that the guy who had the bike before me put on a different tail pipe (you can see it in my avatar picture) I have no clue if he rejetted the carbs, but i'm almost positive he didnt. i took it by the shop today so hopefully when they call me tomorrow it will be a quick easy fix.

Yeah i got the CV34's like you stated. im not sure how to tell if the carb diaphragm is torn or not. just piked up the repair manual for the bike. so hopefully i'll figure it out.

guess what it was. water in my gas tank. the gas cap was so loose that water running down the tank got inside it.

Great news....a lot cheaper to fix than a torn diaphram, those things must be lined with gold for what you have to pay for them.