TOPIC:

Hi all, my 78 kz1000 has a simple problem I hope. The bike runs GREAT when its totally warmed up idles goes through the rpm range no problem. What I want to know is why when its a cold start it coughs a bit at low rpm. The bike starts right away with the choke on when cold, it just wont run great at all at low rpm until its really warmed up. Do I need to sync them clean them? Im not to shure here and im leary on messing with the carbs.

I think most of these old bikes are cold blooded. One of the tricks is bumping the pilot jet to the next size up.

Since your bike starts good on choke and runs well when warm there is most likely no problem with the carbs. However, routine maintenance on carbs such as syncing and basic cleaning is a good idea to keep them running good.

Awesome well, I check the plugs every now and then and they look good it doesnt seem that it is running lean so I think its ok. I just didnt know if running cold was that rough.

The pilot system and choke system control the behavior of the bike when cold. On your model, the pilot system is set somewhat lean so there are a couple things I would recommend.

First, you can richen the pilot system by adjusting your pilot fuel mixture screws located on the bowls toward the head.

LIGHTLY seat each screw noting the number of turns IN you have to make. Then screw them out the same number of turns, from LIGHTLY seated plus a half turn.

You can also do the same thing by bumping up your pilot jets to #17.5 and leave the mixture screws alone. This will also richen your idle mixture.

Keep an eye on your plugs and don't run with choke on any longer than necessary.

Also!!!! The choke picks up gas via the small brass tube on the back edge of the bowl. This tube has a very small hole in its tip and if this hole or the ones on the sides are clogged, the bike will be harder to start and won't idle well with the choke on. Clean the holes with a small piece of wire. Also remove your pilot jets and make sure they are not stopped up any or have deposits on them.

I just posted this same question on a different board looking for some assistance. I had thought I heard there was some mods that I can do to help with this cold start issue. It is around 30 degrees when I set out to work and around 50 when I come home. It take about 10 attempts to get the bike to fire up.
Do I stand a chance at burning up the starter?
I feel your pain.
Jody

If you have to grind away on the starter to get the bike to start, it obviously isn't good for the starter clutch or starter. Read comments I made to the other fella with this issue.