KZ1000 carb jetting

billk · Posted: Mon Sep 28, 2009 5:04 pm Post subject: KZ1000 carb jetting

First time posting so if I do something I'm not supposed to do let me know.
I have a 1977 KZ1000 B1 with Vm 26 1017A carbs. I put on the generic pods and rebuilt the baffles opening them up considerably. At this time I have 25 pilots, 125 mains, 258 0-6 needle jets and 5DL31 jet needles at #4 slot. The bike is running way to rich low end and high end, but if I lean it out it pops mid range after 6 thousand RPM ( holding steady not during accelleration). If I open the throttle wide open running though the gears it doesn't pop.
And it also seriously loads up at the light, running this rich. Bill

Blue · Posted: Thu Oct 01, 2009 4:18 pm Post subject: no pro !

Are the pods you are refering to the air filtration system? I had a problem one time with some "velocity stacks" that had to dense an air element in them. I only discovered the problem when I had them off and the loading up stopped, thinking that what I had done last was the culprit, I re-installed the Stacks and the problem came back, that's when it dawned on me, so I got some less dense foam and was good from there. The symptons you describe seemed awfully close to what my bike did, loaded up at idle and would slam through the gears, no problem, just a guess on my part but easy to try.......Blue

hondacustom · Posted: Thu Oct 01, 2009 5:43 pm Post subject:

you added pods and screwed up the corrct air/fuel ratio

then cut out the baffles and ruined the backpressure

why would it run right

billk · Posted: Thu Oct 01, 2009 5:49 pm Post subject: carb jetting

I thank you for the reply Blue and I'll try that. I know if I put 17.5 pilots in I come off the line like a rocket and it doesn't load up. I guess my problem is the right combination pilot and main. Because the only time it pops is over 6,000. I've had 17.5's in, but it seemed like I couldn't find a main to match it to stop the popping which I'm thinking is unburnt feul in the exhaust firing on the exhaust stroke. One main it's starving the next it's popping? So at this time I need to find a different combination. I also need to pull out the needle jets to see if there 05's or 06's. The book I have says they should be 05's and I only supposed that they were. OOPS. So I'll check that and go back to eather 17.5 or maybe even back to the original 15's. I guess it's going to be another long weekend. And yes I'll check the pods which are for the air intake and it is possible that it's not getting enough air at high RPM. And the pods are made by EMGO Thank you

KirkN · Posted: Thu Oct 01, 2009 6:39 pm Post subject:

Don't neglect the jet needles, too.

IIRC, rule of thumb: the pilots are 0 ~ 1/4 throttle, jet needle from 1/4 ~ 3/4 throttle and mains from there on up. The jet needle, even though it draws fuel through the main, actually does the fuel metering in that range. And that means throttle position, which is NOT necessarily RPM. That is, 6000 rpm (on a 9000 rpm redline) does NOT necessarily = 2/3 throttle even though it's 2/3 the total RPM.

IIRC, the jet needles can have a different taper from one to the next, and of course, they can be raised or lowered in the throttle slide.

So, even though you're playing with pilots and mains, perhaps the answer lies, in part, in different jet needles.

Or not. Very Happy

Keep us informed. I'm always interested in others' jetting moves - what works, what doesn't, etc.

Kirk

billk · Posted: Thu Oct 01, 2009 6:51 pm Post subject: air pods

Thanks KirkN, I went out and pulled one of the pods off and looked at it, and it's actually a paper sandwiched in wire mesh and they look to be sucked inword. I believe Blue may be right on. I'll probably have to invest in a decent set of pods. Thank you

Blue · Posted: Fri Oct 02, 2009 3:02 pm Post subject: Air flow and popping

Since I've been down the air flow path, which sort of negates other things, now I'm curious about the "popping" for sure is it coming out the exhaust? or is it "sneezing" in the carb, Harleys , ( the older carbed ones) when they changed to meet fuel emission standards in the early 90s, went to a needle that was stepped, so when you went for power to abrubtly they "sneezed" and popped in the carb, this was on the big twins, however they didn't change the Sportster 1200cc and the cure for the big twin was to use the Sporty needle because Harley didn't change them for another 2 years, so I've always ordered a pre-91 Sporty needle to cure the problem. Just wondering if the popping is fuel trying to get burned in the intake. Disturbing all the stuff you did almost always ends with these problems, however, in the past, present and future, advances in technology have involved everything you have done and even the pros struggle a bit to get it right, keep on.........Blue

billk · Posted: Fri Oct 02, 2009 4:32 pm Post subject: carbs poppin

Appreciate the info Blue, but it doesn't pop during accelleration it pops when you level off over 6000. When I turn my head, I can here it through the pipes. I looked at the pods and they are quite small, so I ordered larger ones this morning. I should probably get them about mid week. I'll let you know what happens. I've also got a friend with an older harley who has that sneeze. I'll have to pass that information on. He replaced the carb a couple of years back and he says it been doing that for awhile. I don't know if it's been doing it from the carb change or what, but I'll ask him.
Thank you,

billk · Posted: Fri Oct 09, 2009 5:34 pm Post subject: popping carbs

I'd like to thank those who gave me tips on correcting my carb issues. And a special thanks to Blue who hit the nail on the head. It was the Emgo pods, they have a crome end cap and not enough surface area to get the volume air that is needed for a KZ1000. I could get the bottom end with no problem, but the top end would pop after 6,000 RPM. I switched over to UNI foam filters that are 5 inches long, 8,000+ RPM no more popping. 20 pilots, 127.5 mains and it's a rocket. Tomorrow I'll take it for a longer ride and check the plugs and adjust as needed. Again thanks to everyone with actual answers. Oh, by the way (hondacustom) you should probably stay on the porch son. I'm moving through my 50's and it's still all about performance. And I ain't ready for no rockin chair yet. I have all the parts to return it to stock including the baffles I took out. Maybe some day somebody will put them back in, but it's not gonna be me. Have a safe one guy's.

Blue · Posted: Sat Oct 10, 2009 4:59 pm Post subject: glad it worked !!

There are many instances that affect what is trying to be achieved, assume that everything you were dealing with was done prior to your ownership, now there is the making of a real horror story. My best guess is that (hondacustom) has dealt with more than one case of that. I restore and chop depending on the best case scenario, so at 65 I tend to sit on the porch sometimes myself, as is the case with my Harley, best left as is, I mean if Harley can't get it right, (and boy they try). On the other hand, let me grab on to a trashed GS750 that is beyond resto. and I have at it, so, to each his own and may we all learn from it........Blue

Steve Searles · Posted: Thu Oct 29, 2009 10:40 am Post subject:

Well guys, I agree with both scenerios but lean towards keeping the air intake and exhaust back pressure as designed from the factory whenever possible. Having said that, there are times and reasons to go for modifications such as racing, or a machine that is beyond restoration as Blue mentioned. I have rejetted numerous times and it is like chasing your tail. You may get low end right but high end suffers. Or the main is good but it won't idle or .... If you can get the bike running well at all RPM ranges with the pods and a pipe that is great and a blast to ride. Just takes alot of tweeking. In other words, It's all good!!

Steve Searles · Posted: Thu Oct 29, 2009 10:42 am Post subject:

BTW Blue. I might be getting a Honda 550 that is beyond resto and I might just do what we are talking about. Cuz the pipes are rotted, airbox shot, etc.

fasterspider · Posted: Thu Oct 29, 2009 2:01 pm Post subject:

It is a proven fact that pod filters rob your engine of power even when using real machanical slide carburetors.
Race bikes do not have air filters, they have velocity stacks.
It is also a known fact that pod filters and jet kits are designed for the sole purpose of relieving a sucker of his cash.

Blue · Posted: Thu Oct 29, 2009 4:09 pm Post subject: 550 eh !!

Steve, that'd be a good one for a ratbike, hand bent pipes by the local muffler shop, with heat tape. A pair of old fire extinguishers, gutted and hung over the backstrap as gastanks, dog bone risers and drag bars, rear shocks moved back 2-3", bobbed out rear fender, suicide shift, ok, that's enough..Blue