Just wanted to thank you for posting this. I picked up a 78 650. It ran great at WOT, but idled for crap. The guy has k&n’s on and not a vacuum line in sight. I noticed from your video where you say to vent it @ 3:32 he had it capped! I removed those caps. turned in the idle screws, then back out (evenly on all 4) until it held on its own and its like a new bike. I know this is simple stuff, but it became much clearer using your video as reference.
What I like about this guy's bike is that it is clean. Its not a trailer queen or a museum piece but it's obviously meant to be a runner. Look how clean the Master cylinder is for instance. Nice touches. And what about the polish job on the engine covers? Nice.
Great video. Thanks for all of the helpful info. My buddy bought me a jet kit as a gift for my pods but I have yet to install it. Thanks again. Awesome looking bike!
this video has helped me so much over the past year since owning my 79kz650, always forget the idle screw in which way does what... i know its a 11 year old video but man, i love your kz, much prettier than mine lol.
I'm glad you found this helpful. The overflows just go between the rear of the case and the swing arm and trim to length. Thank you for watching and ride safe!
I have found that Dynojet makes the best kits for the average backyard mechanic. Just contact them and tell them the specifics of your machine and they'll send you the appropriate kit with easy to follow directions. It eliminates all the guess work, just install and ride.
To replace the petcock is just two 10mm bolts and a gasket. Very simple, remove the tank and tip it up so the fuel is not covering the petcock and then change it out. Don't forget to plug the vacuum port on the carb too! Mine is a standard Kawasaki part for an older machine.
Don't really have much two stroke experience, but the same applies. Just going bigger does not mean more power. I know that two strokes respond very well to a good exhaust pipe with an expansion chamber. More power depends entirely on the engines ability to breathe efficiently. Think of it as an air pump. Without modifying the engine to enable it to move more air, gains in power will be relatively small. You can however optimize a stock engine by allowing it to breathe well and proper jetting.
Good day i have 4 z650 kawasaki s motorbike i am starting fire up one by one two bikes turning to Bobbers rebuild frames thanks for sharing your info Anton South Africa
@redshirt489 Hey red : These air filters look cool and makes the bike sound better at full throttle. The power gains you will get are small, if any ,and you will have to install a jet kit so the bike will run right.
I think your CSR uses different carbs than mine but if the port has vacuum while the bike is running and you are not using a vacuum operated petcock it should be plugged. A port that has no vacuum is simply a vent that is open to atmosphere and should be left open . If you still have an airbox hoses should run from the vents to the airbox. If you are running pods the vents should be open with no hoses attached. Overflows are almost always found on or near the float bowl at the bottom.
Thank you for posting this. I hate carburetors, and have gotten my KZ650 to an acceptable, but not perfect tune. I like the stock airbox for even flow to all carbs even with a crosswind. I did use a K&N element though. My issue is that sometimes it runs like a dream, and other times its as though it is getting fuel starved on rapid acceleration, but not consistently. It's a bit maddening. mine is an 1980 F1 with mikuni carbs they only made for that year and accelerator pumps.
@@natehoule567 I learned that a lot of the issue was that a coil was going out. I bet you if you get a new pair of coils and clean up your points or switch to a Dyna s kit you will get way better performance.
I know nothing about Fiats, but I will say that the carbs will have to be sized properly and jetted to feed that engine. Just hooking up four carburetors won't work and using four of the same ones the car uses now definitely won't. Unless you are going to modify the engine , say with high lift cams and high compression, I think gains would be nill by going to a four carb setup. It would be much simpler to update the stock setup with a modern two barrel and an exhaust header to start.
Whats up Thumper? All I can tell you now is that the jet kit came from Dynajet and if you contact them and give them your setup, they will send you the appropriate jets and needles.
I'm sorry to say that I have no experience to share about our type of carb. That being said, I'd think the process of changing jets and needles should be basically the same. The slide uses a diaphragm rather than mechanical linkage, and access to the jets should be inside the bowl as usual.
Are you using the original carbs or the replacements? You installed a jet kit, or you just went bigger on the jets? Without knowing your setup or what you have done , I can't really say what the problem could be. There are too many things to consider. Stick to the basics of air, fuel and spark. How did it run before you made the changes? Did you mechanically synch the carbs? What about valve lash? Just so many things to check.
I have the 78 Kz650D SR OEM carbs with just the one mixture screw at the bottom. I have vacuum lines on the bottom of all 4 carbs. On carb 2 I have both the vents capped off as well as a cap on the 4th carb. Is this incorrect?
I have an 81 KZ650 CSR; Thanks a million for showing me the "vent-ports" I mistook the left-hand vent-port for an overflow and put a hose on it. By removing the hose, my bike rests 1000RPM's in each gear. One question: My petcock has two valves, and there are two ports on the carburetor; is one port the gravity feed and other automatic? do I need, or should I use both?
my acceleration on my 1978 kz650 seems kinda sluggish. i feel like i really have to rev the engine hard to like 5000-6000 rpm to get it really going.....are these bikes actually hard to get to 100mph? it only has 5 gears after all...maybe a carb cleaning is in order???
@colmmorley So you put the 250 into a buggy? Cool. My guess would be too lean on a cold start. If you have removed to air box and done something to open up the exhaust, you really need to re-jet to get your machine to run it's best. Its'going to be making less power than the stock Ninja setup had, so a re-jet will get the power back and then some.
@redshirt489 I can't tell you how to do it from here. Get yourself a manual and use it as a guide. I'd check ignition and the general state of tune before you go tearing into the carbs. Plugs, wires timing, ect. Keep in mind that the fewer mods you make, the more reliable the bike will be.
bike looks great man! thanks for posting this video, you solved one of my issues by explaining the vacum port. the clymer manual failed to mention the location of the vacum port for the vacum petcock. the other question is: the over flow tubes from the bottom of float bowls are just tucked in by the swing arm, and just dangling, is this correct?? I greatly appreciate your help!
Where do you get the Jet Kit From? And do you happen to have any recommendations? I took the air box off & replaced with pods on my 79 KZ650 and cannot make it accelerate without falling on its face.
Nice bike! I own a Z650 F2 1981 with the same carbs. Do you have size details of the jet kit? Did you change the pilot jet? Did you alter the height of the needle jet? It sounds great!
nice video. I need help with this, i just installed pod filter on my 1981 650 csr kz and now the bike will idle but once i give it throttle it bogs out, im assuming i need to change the jets but i have now idea where to get them or what size, any advice?
how much is a jet kit? and where would i get one? and also i have a problem that another youtuber is having. i have 2 pistions running good( firing and getting hot) number 3 and 4 but number 1 and 2 are not getting hot like not getting gas to them. so my question is to you how do i get the carbs off? i trued but the air box is in the way and i think i saw a clamp screw on the carb do i unscrew that and they will come off or what do i do to get them off? thansk
thanx for dat info ill go in for the double barell setup 1st. i also have a 72 jawa 250 2 stroke, and i want to increse the power n pickup, so should i go for a 100cc/175cc 2stroke carb with the biggest possible jets or stick to stock carb with upgraded jets or should i go for 350cc carb??
Just got a 82 kz 650. It wouldn't idle cleaned the carbs now it idles great but won't take any fuel when u rev up. It backfires. Do you think it's a vacuum leak on the boots.
@@yellowbusguy the coils seem to be fine. It will sit there an idle perfect but want take any fuel when u Rev it. Could that be the points off? Or the points wasn't set up right with top dead center
The fuel squirters aren't squirting out fuel when you twist the throttle. I guess the accelerator pump isn't working or those fuel squirters are clogged
I have the same bike. grew up On a 78 Honda CBK, but sold it years ago.. want to trick my 80 kz F1 and like what you have done to yours, the guys did this quit a bit back in the late 80s when I road with them, Kerker header, jet kit, pods, etc..any possibility to get a pic or two of yours as a reference?
On the 70's kz650's with k&n pods and a Kerker with no baffle, just the cone, we's go with 120 main jets and enriched the idle mixture by screw alone and they'd come to life.
Good video. Mine is sometimes doggy under hard accelleration between 4500 and 6000. It pulls strong in the same range if I am just a little more gentle on the throttle. Any suggestions about where to check. I've gone through the carb many times and never found any obstructions or gunk. I have a fairly free breathing exhaust- a bastard conglomeration of a Kz1000 early kerker header and an unknown muffler that is mostly a straight pipe now. Jets are unknown. Stock airbox with K&N drop in. Carbs are bench synched and the gauges read synched at that setting. Compression is excellent according to the shop. Mileage is around 14k? It clearly makes a lot more power than the several other Kz 650s I have tried. It starts on the first kick.
Mine does the same sort of thing, if I roll off the throttle just slightly, it pulls harder. I suspect the needles on mine is a shim too high or so and it's a little too rich at WOT. I don't run mine that hard so I've never gotten back in there to make the change, it runs so well everywhere else it isn't an issue for me. I'll ride the ZRX if I want to go fast. Do the plugs look rich?
A bit. But the feeling is like running lean or getting a little out of sych. For a while I was convinced that the petcock was restricting flow and fuel starving me. I even swapped that out.
actually m planning to buy an old 55 classic fiat 1100 its has got 4 cylinders n one carb..now if i put 4 carbs(same fiat carb) on each cylinder..will i get more power?? mileage n emission not any issue??
question for you my good man, ive got a 1979 KZ650. pretty much looks just like yours. I put pod filters on it and so i took off all the air hoses that go from the airbox into the top of the engine. My question is, what did you do to the two holes on the top of the engine? did you just plug them or something?
oooooh ok. hmmm i dont know really where mine came from. i bought it used from some guy out here. i removed the airbox to put on pods which had kind of a long tube that went from the airbox and it ran to the valve cover i believe and it split into two tubes which go into the cover. thanks anyways for replying!
Sounds like a typical passive air system. All it does is introduce air into the exhaust stream to clean it up for the EPA. Depending on the system, you may have to block off those ports in the head. Removing it does nothing for performance but it will stop the popping and crackling from the exhaust on deceleration.
Hey I have a couple questions for you I need to know if this is the original fuel tank for this bike and what year and model is it. The kz650 I got came with an extra tank and the one I am keeping on it looks like this one you have on yours. but the knob on the petcock is broke and I am having trouble finding the right one.
I'm mostly sure this is the original tank, it is a 1978 C1 . These petcocks were common on many models. This is NOT the petcock the bike came with however, the bike came with a vacuum operated type. This one is the manual kind. I recommend using the manual type, the vacuum models don't last very long before they begin to leak. I replaced them twice within 2 or 3 years. I've had this petcock for at least 20 years.I think any one called out for any KZ should fit.
Oh the 3 other wires are brown, blue and blue/ pink. I have tried white to blue, black to brown and white to blue, black to blue/pink. Anyways this is my only transportation and I have to work tomorrow so any help would be greatly appreciated.
Can someone help me please! I just got a 79' kz650 looks like the ignition system wires got yanked out. 2 purple wires come from system each with 1 black,1 white wire. The one still connected has white to green, black to black. But there are 3 wires the other 2 can go to. Have tried it a couple different ways and the bike starts and runs both ways but blows main fuse after about 50 yards. Please help
No... Someone I got if off said it sputtered... And hasn't been ridden for a few months.. Choke on it starts up and runs once I out the choke down dies... I slowly put the choke down and mess with the screew that opens the throttle... Still can't keep it on with he choke fully down idles around 1500 and I can't ride it in first gear ... Everything is stock.. The only screws I see are under all four bowls...but those look like they just let out fuel...so I see no way to adjust air mixture via outside the carbs?
Kind of hard to be of any help here in my PJ's. Those screws adjust idle and low speed mixtures, if those aren't in the same place as the one's in my video, you may have a set from a newer model. Look under the carb at the front of the bowl for a screw that goes up into the body around where the bowl joins the body of the carb.
If there are no baffles in the pipes, 120 mains will make the bike fly. No need for a pilot jet change. This was with the mechanical slides, not the cv carbs. Nice video. I've subscribed.
Fuel float(s) may be stuck. If it sat with old fuel in it, the carbs may need to be gone through. Make sure your battery is healthy and the connections are clean and tight.
We finally got it got it, Had to rip another one apart and yse parts from both to make it work she still back fires alittle bit but she x Dosent leak fuel anymore... We have a 77 , 78, and an 08
The vacuum on number two was originally used for a automatic petcock. There are vents that would have gone to the airbox that should be left open with no hoses. If your idle is all over the place but calms down when you open the throttle, look for vacuum leaks. No pumps of any kind on this series of KZ and no emissions.
