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mikuni 33 smooth bores vs. lectron 40's
- bwill166
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- racer54
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1980 LTD (changed over the years), 1979 LTD (being rebuilt), 1977 KZ turbo and various KZ's in various states of build. KLX110
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- DFIGPZ
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1984 750 Turbo
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- taildragger1197
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As the last poster said, 40 may be one size too big. find some 38's. You need to match your carbs closer to the intake port and valve size.
Union City, Tennessee
1979 KZ1000 LTD B3
1979 KZ1000(1260)LTD S/G Pro ET
1993 ZX11 D1 Ninja
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- timebomb33
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1973 z1 2-1974z1-a,2-1975z1-b dragbikes1015cc+1393cc, 1977kz1000,1978kz1000,1981kz1000j, 1997 zx-11, 2000 z12r,1428turbo nitrous pro-mod and a shit load of parts thats all for now leader sask.,CANADA
I THINK MY POWERBAND BROKE
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- DFIGPZ
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timebomb do you happen to need a big block ? i have a brand new FBG big block and a set of JE 1397cc 14.1.cr pistons Bored, honed, decked, oringed ready to go brand new.i'm running 40 lectrons on a real mild big block combo with a kz head that is actually set-up for 33's in my 7" chassis super consistant and fun to ride but it way more carb than i need with this head, i'm going to get a set of 38's this winter for it and put my 40's on a big bad combo that's going in my cartire bike this spring. the 33's i'm going to use on a 1200 motor that i'm putting together for street bike shoot type bike i'm building. so i guess the answer to your question is i like them both but definitly lectrons for the dragstrip if you have the choice.
1984 750 Turbo
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- timebomb33
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1973 z1 2-1974z1-a,2-1975z1-b dragbikes1015cc+1393cc, 1977kz1000,1978kz1000,1981kz1000j, 1997 zx-11, 2000 z12r,1428turbo nitrous pro-mod and a shit load of parts thats all for now leader sask.,CANADA
I THINK MY POWERBAND BROKE
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- DFIGPZ
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just email me direct at b.flood@myactv.net i will be away from time to time i will reply and send pics.pm me we will talk
Barry
1984 750 Turbo
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- larrycavan
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Well i can only lend you my experience as i have put together many kawasaki drag bike engines. now if i had the choice between 33mm round slides or lectrons I would pick lectrons W/O hesitation. that being said the mikuni flat slides are a much nicer carb than the old round slides, but i would still favor the lectrons for a drag bike application. as far as what cylinder head is on the engine if its a Z1-KZ style cylinder head i would use a 38mm lectron. I know a lot of racers run 40mm lectron with KZ style head and a lot of my customers rum them but i have never seen any gain using 40mm. My own drag bike [ now sold ] was a 1294cc with KZ style head and 38mm lectrons and it went consitant 8.80-8.90s with me on it at the time i weighed 220lbs. I've dyno tested my bike with 40s and 38s and the 40s made slightly more top end Hp but the 38s made better overall hp. now if you had a good ported "J" or 83/84 "GPZ" head i say i would used 40mm. Larry what are your thoughts on this ? i came to the conclusion that a early head cannot flow the air to warrant a 40mm carb. I would be interested to hear your thoughts.
My thoughts are simple " YOU are right on the money"
KZ runners are pretty limited to what can be cut away at the port entrance so 38's are the "effective" limits.
To really make use of 40mm carburetors a J head pushing 105 - 110 CFM is more appropriate.
Lectrons are a heck of a carb in certain respects and a total piece of shit in other respects. They make HP. They have excellent throttle response.
What they don't do is idle stable below about 2500RPM. They also can be a bitch at the line after the burn out because they want to idle even higher. It makes the bike hard to get into first gear..
Bracket racing is about repeating the number [for most people] so which ever carburetor you can tune to do that will work just fine.
Let's look at some real world aspects of a rack of conventional carbs vs Lectrons.
Do you like to have the bike idle good and return to idle reliably? Then conventional rack carbs are the ticket.
Do you need to wring the last bit of power out of the engine? Then Lectrons are the way to go.
All kinds of people go drag racing. We have a crowd that only goes on T&T night for bragging rights. Then we have a crowd that heads back on Saturday to hopefully bring home the money :laugh:
Funny part is on more than a few occasions...it's a fat chick on a snowmobile that brings home the money!!! :laugh:
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- larrycavan
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If this is a drag race only engine, you have only ONE throttle position.....WIDE OPEN. Go with the Lectrons. They may be worth as much as .10sec in the 1/8. More in the quarter. 33 smoothies will get the job done though if your on a budget(if you can find them nowadays cheap enough) and I think they look sweet with a set of stacks! :woohoo:
As the last poster said, 40 may be one size too big. find some 38's. You need to match your carbs closer to the intake port and valve size.
I have a nice rack of 33's available if anyone is interested. PM me for a price.
Larry C
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- timebomb33
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1973 z1 2-1974z1-a,2-1975z1-b dragbikes1015cc+1393cc, 1977kz1000,1978kz1000,1981kz1000j, 1997 zx-11, 2000 z12r,1428turbo nitrous pro-mod and a shit load of parts thats all for now leader sask.,CANADA
I THINK MY POWERBAND BROKE
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- larrycavan
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another thing to look at is your valve sizing if your only running stock sized vales does it make much sense to use a carb that is 3 or 4 mm bigger. thats the main reason i'm going down to 38's for my 7 inch bike i'm using 37.5mm valves in it.
Good thinking Tim Glad you're back online BTW.
I'll tell you what bud. I don't even bother with 37.5 intakes anymore unless someone absolutely wants them. I found some nice stainless 37mm J intakes that make life so much easier.... Price is excellent also. If you want some, let me know and I"ll get them for you.
Larry C
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