Cold Blooded 650

I have posted some of this over at kz650.info but I figured I could post it here to.

My 77 KZ650B-1 has been hard to start when cold since the day I got it. I had my routine figured out, choke on, a short hit of the starter, two easy kicks then one good kick. Starting fluid has been used succesfully but is not good on the motor. As I get older this kinda sucks because I know it should not be like this, my 900 has never ever given me a fit when cold.

My carbs are dead on I believe. Once started and warm she idles and behaves excellent.

I am running points and factory coils, I put a relay on the coils because I was getting 10.4 volts to the coils. I now have proper voltage to the coils. (Old Man Rock will give me hell for the relay, but at least I did'nt say WG coil mod) :laugh:
Ignition timing is dead on.

I have a brand new battery with the proper voltage
I have "not" checked valve clearances yet.

Does anyone have a 650 with points and factory coils that starts up when cold?

I have a dyna ignition and coils on my wish list but I am financially embarrassed at the moment.

What else am I missing here? This has been this way for years and I just dealt with it, but since my 900 stars so easy I am on a mission to get my 650 to start just as easy.

K, Offer this, I have a '78 kz650 B2,And like yours' was cold blooded & hard starting for years. While bike ran well once warm, It required at least a minute of warm-up before riding, & even then if temps were cool required 3-4 miles before became "happy", And for cold starting the elect. starter was mostly useless.leading me to assume the starter was drawing so much current that my coils weren't saturating. I was wrong... after countless carb cleans, I apparently FINALLY got it right, My vm24's (mixture screw only, some have air & mix.screws) have 2 fuel mixture bleeds. 1 at lip of slide, (pilot jet circuit) 2nd 5-6mm downstream,(Mixture screw circuit.) when cleaning pilot circuit (spray carb clnr) remove pilot jet & spray thru its mound, & verify both these bleeds flow freely, you should get a strong stream at both, and through the pilot air jet at intake throat. while things are apart, verify not only choke plunger/passage is good, but that the metering tube which enters float bowl is clear, and the choke jet (invisible,residing in float bowl passage which accepts metering tube) is clear. I upped my pilot jet from 15 to 17.5, If bike sits for more than a couple days between rides, and you have a vac. petcock, switch to prime for a minute before cranking. since my latest trip to carb land, bike likes full choke, no throttle & a prod of button to start, comes to temp quicker etc. hope something here helps.G

gane wrote:

K, Offer this, I have a '78 kz650 B2,And like yours' was cold blooded & hard starting for years. While bike ran well once warm, It required at least a minute of warm-up before riding, & even then if temps were cool required 3-4 miles before became "happy", And for cold starting the elect. starter was mostly useless.leading me to assume the starter was drawing so much current that my coils weren't saturating. I was wrong... after countless carb cleans, I apparently FINALLY got it right, My vm24's (mixture screw only, some have air & mix.screws) have 2 fuel mixture bleeds. 1 at lip of slide, (pilot jet circuit) 2nd 5-6mm downstream,(Mixture screw circuit.) when cleaning pilot circuit (spray carb clnr) remove pilot jet & spray thru its mound, & verify both these bleeds flow freely, you should get a strong stream at both, and through the pilot air jet at intake throat. while things are apart, verify not only choke plunger/passage is good, but that the metering tube which enters float bowl is clear, and the choke jet (invisible,residing in float bowl passage which accepts metering tube) is clear. I upped my pilot jet from 15 to 17.5, If bike sits for more than a couple days between rides, and you have a vac. petcock, switch to prime for a minute before cranking. since my latest trip to carb land, bike likes full choke, no throttle & a prod of button to start, comes to temp quicker etc. hope something here helps.G

i agree with the above stated fixes. i have the same bike!! although i do have coil mod, dyna ign and coils. i always thought these were quite cold blooded but once it starts and you ride it a mile its fine

fixer5000 wrote:

gane wrote:

K, Offer this, I have a '78 kz650 B2,And like yours' was cold blooded & hard starting for years. While bike ran well once warm, It required at least a minute of warm-up before riding, & even then if temps were cool required 3-4 miles before became "happy", And for cold starting the elect. starter was mostly useless.leading me to assume the starter was drawing so much current that my coils weren't saturating. I was wrong... after countless carb cleans, I apparently FINALLY got it right, My vm24's (mixture screw only, some have air & mix.screws) have 2 fuel mixture bleeds. 1 at lip of slide, (pilot jet circuit) 2nd 5-6mm downstream,(Mixture screw circuit.) when cleaning pilot circuit (spray carb clnr) remove pilot jet & spray thru its mound, & verify both these bleeds flow freely, you should get a strong stream at both, and through the pilot air jet at intake throat. while things are apart, verify not only choke plunger/passage is good, but that the metering tube which enters float bowl is clear, and the choke jet (invisible,residing in float bowl passage which accepts metering tube) is clear. I upped my pilot jet from 15 to 17.5, If bike sits for more than a couple days between rides, and you have a vac. petcock, switch to prime for a minute before cranking. since my latest trip to carb land, bike likes full choke, no throttle & a prod of button to start, comes to temp quicker etc. hope something here helps.G

i agree with the above stated fixes. i have the same bike!! although i do have coil mod, dyna ign and coils. i always thought these were quite cold blooded but once it starts and you ride it a mile its fine

I will have to pull the carbs(again) and see what I can find. They all take some time to get to operating temp, it is the initial starting thats giving me fits

My 650 used to start way too easy when it was cold and I knew that was not right. I could take it off choke almost right away and ride off. Found my floats too high and now it needs choke for a few minutes. But I'll tell you the ONE thing that made a 110% difference in starting and that was installing a Dyna S! I'm running stock exhaust, air box (K&N filter) and stock jetting (102.5, 15, 4th notch) Turn on prime for a minute, full choke, no throttle and it lights off before I can remove my finger from the starter button! I was so amazed at the difference from points to Dyna. I used to show my wife all the time and she would just give me a "that's nice dear" look and walk away (some people just don't understand). If you can swing it ($120) I would highly recommened a Dyna for sure!!

Granted, different carbs but let's be real for a moment, pretty much all carbs have the same conceptual theory of operations....

As in accomplishing my CR jetting, in my research in carb theory 101, I have found nearly all to be ~ the same...
Pilot (slow jets) and needle cli[ ositiions for start up, idle to mid range...

In my case, warm or cold, could not use the choke plunger AT ALL due to running to rich on the jets. Went leaner where I was now able to choke ~ 1/8th up for cold start up... Now with the next size needle being leaner, 1/4 to 1/3rd up for cold start...

Out of the Keihin literature...
If you need a full pdf copy of this let me know...

As can be reviewed in the 2 jetting curves between old Mikuni VM carbs and new CR specials... almost identical...

BTW... Since it was mentioned, another reason I'm not for the coil mod... Band aid of your carb jetting as well...

Sure to get home while on a rdie no doubt but most use this as a fix for carbon plugs when the real culprit is most likely in your jetting and carb ideal operations....

Got my Dyna coils and ignition for my 650 so maybe the cold blooded starts are a thing of the past. I will be installing it today if I feel up to it. I have been sick for a few days now and still feel like crap.