Right back to square one.

I thought I had my whole running lean issue figured out but now I have some new symptoms. All i have done so far is change the oil and put in new plugs. The plugs arent really white and crusty, but more of a gray color so i dont know if im still running lean or not. hereare the plugs





I have always had issue when starting up. I will have to sit there and adjust the choke up and down the whole time it is warming up just to keep it running. Also, if i hit the throttle at all during warm up it will wind up the rpm's and they will stay high like its stuck until i cut the choke a little. After its warm I can kill the choke and adjust the idle knob and im usually good to go. Now the biggest issue is that when I am riding it seems like 2 of my cylinders cut out and I start to bog down. Usually this ends with the bike eventually stalling and me trying to restart it just to get home. Most of the time after I get it fired back up it will even back out again. If it has anything to do with carbs ill probably end up taking it to a mechanic which I dont want to do but I just dont have the know how. Really need some advice on this.

Sorry here is a link to those pictures

www.kzrider.com/forum/2-engine/601207-ch...gs-what-do-you-think

Which model bike are we talking?

If it has an electronic ignition, it could be one of the pick ups cutting out when it gets hot/warm.

What jetting, air filter and exhaust you using?

A Colortune plug will tell you if your jetting and air/fuel mixture is good at idle.

Kz650 c1. Not sure on jetting. It's been bored, stroked, and cammed (supposedly). Using a zr7 4 into with slip on muffler and stock air box

Possible issues could also include:

Perhaps pilot circuits are not in perfect as-new condition.
Same for enrichener circuits.
Fuel levels might be incorrect.
Pilot jets might be the wrong size.

Most of the time after I get it fired back up it will even back out again -- :huh: Not sure what this means.

First-time carb cleaning is often easily learn-able, except for OMR who had his usual difficulties. :lol:

Good Fortune!

What I meant was that after I finally get the bike going down the road again, it will start running decent again about 30 seconds later. I'm getting ready to post a link to a video of the bike running. It almost sounds like it's choking but idk how to explain it very well. You can really hear it when the seat is up

I think I might have had an epiphany last night. The position supposedly had this thing bored and stroked? Well it ran like a dream when I rode it home so correct me if I'm wrong but here's what I'm thinking. Bored = higher compression. Higher compression = premium gas. I've been pumping 87 this whole time so maybe that's my problem. I'm going to drain the gas today and see how it goes

Bored maybe, stroked? :lol: I have had a bored out 900 for 40 years. I run regular gas with no problems. It might be leaning out. Pics of the plugs? I can't tell you how many times I've heard the bored and stroked tales. Asking for the paperwork usually stops that crap. :whistle:
Steve

It might help if you can find out exactly what the guy did. maybe he went with bigger pistons, maybe not, especially if he can't answer simple questions. If he says it's been stroked, ask him how. whatever he did, ask exactly what he installed. the answers should be easy --- it's not that complicated. there's only so much that can be done, just common kz stuff.

Well wouldn't you know it, I'm having a hard time getting him to answer me back on these questions I have. What a surprise. I'll post a link to the pictures of my plugs from the other day. Im more convinced now than ever that I'm running lean though. When I blip the throttle during warm up it will hang up on whatever rpm I stopped at. Also, I have very little gas coming through the fuel filter. It's maybe 5/8 air in there but that may be reasonable since it's a vacuum petcock. Sounds like I'm going to have to tear into the carbs and see what jets he has in there etc etc

www.kzrider.com/forum/2-engine/601207-ch...gs-what-do-you-think

Could be fuel starvation. Have you tried running it on prime? Get a can of carb/choke cleaner and spray through the passages. The pilots are very small so a guitar string of strand off a wire brush should go through them to make sure they're clear. Don't hit rubber parts with the spray. Braggarts aside you may have gotten a very nice bike from a guy that was ether too stupid or cheap to get it running right. :whistle: A valve adjustment check should be done before jetting the carbs.
Steve

Is the video showing that there's not a vacuum hose attached to the petcock?

If so, is the vacuum nipple capped/plugged on the carb or carb holder where the missing vacuum hose is supposed to be attached?

An open (uncapped/unplugged) vacuum nipple on any carb or carb holder usually results in a large air leak.

Video indicates a racing idle with the choke OFF.
Was the engine already warm when cranked and started in the video?





Good Fortune!