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Are these bikes generally cold blooded?
- leorider
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07 Aug 2011 20:13 #467553
by leorider
78 KZ650B
Are these bikes generally cold blooded? was created by leorider
I have been working on this bike for quite some time and am now working on the carbs. Carbs have been totally cleaned out but I wanted to see what the stock jet settings are on these carbs. Its a 78 KZ650B. Mikuni carbs but not sure exact model. I know it has airscrews and no accellerator pump. I know it has 110 Main Jets, 17.5 Pilot jets. The needle c-clip is set on the second groove from the top. The airscrews are 1/2 turn out from lightly seated. Stock exhaust. The bike has pod filters but I do have the stock airbox but need to get new rubber boots for it from Z1 as they are in real bad shape and cracked. Also I lost one of the mounting brackets that slide in the back of the airbox. I will probably try to fabricate a bracket. Should not be a big deal. When I ride this bike cold it starts up no problem. When cold if I go 3/4 throttle to WOT it totally cuts out but as the bike warms up about 3-5 minutes the bike runs almost perfect from just what I feel. When warm and I go 3/4 to WOT it has a slight stumble for a split second but it GOES nicely. I figured the bike is probably too rich at the main jets so I had some 102 main jets and put them in. Now the bike seems worse off. Should I stick with the 102's and maybe try adjusting the clip on the needle?? I need to order some jets and probably start over by putting the bike back to stock. The previous owner told me he put the larger pilot jets in because it "warmed up" faster. Not sure if this is correct. It might be but I just don't know. Should I just go back to the 110's and live with it by letting it warm up the 5 mins all the time?
78 KZ650B
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- Patton
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07 Aug 2011 23:41 - 07 Aug 2011 23:43 #467604
by Patton
Where jet needle has 5 groves for different clip positions, 2nd from the top is next to leanest.
Would change to the middle clip position, which raises the tapered needle higher in the needle jet to provide a richer mixture in mid-range.
Would leave the pilot jet alone, at least for the time being.
The main jet has very little if any effect on warm-up time.
Good Fortune!
1973 Z1
KZ900 LTD
Replied by Patton on topic Are these bikes generally cold blooded?
leorider wrote: ...needle c-clip is set on the second groove from the top...previous owner told me he put the larger pilot jets in because it "warmed up" faster. Not sure if this is correct. It might be but I just don't know....
Where jet needle has 5 groves for different clip positions, 2nd from the top is next to leanest.
Would change to the middle clip position, which raises the tapered needle higher in the needle jet to provide a richer mixture in mid-range.
Would leave the pilot jet alone, at least for the time being.
The main jet has very little if any effect on warm-up time.
Good Fortune!
1973 Z1
KZ900 LTD
Last edit: 07 Aug 2011 23:43 by Patton.
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