Mikuni Kogyo Carb identification

DFIGPZ
Offline
User

13 Dec 2015 12:05 #702982 by DFIGPZ

Replied by DFIGPZ on topic Mikuni Kogyo Carb identification

I do not understand why people think they will not work on o 650 ? Way back in the 80's I did a KZ650 for a customer 720 wiesco kit street cams lightly ported head and a set of 29 Mikuni smoothbores and it ran and idled flawless like 900 rpm and I do not remember doing much to them :S

1984 750 Turbo

Please Log in or Create an account to join the conversation.

zukdave
Offline
User

13 Dec 2015 12:30 #702987 by zukdave

Replied by zukdave on topic Mikuni Kogyo Carb identification

They can work work on a small motor if you spend the time to tune them.
I think for the avg. home mechanic they can be a pain,
With mine I think my issue is they need larger idle air bleed jets but since I want a more
modern carb. like a flat slide or the CR special so I'm done with them.

1980 KZ650 F1
ZX750A1 motor.
Wiseco 810cc kit.
Zukiworks racing ported head.
VM 29 smooth bore's.
Dyna 2000 Ign. w/Dyna mini coil's
APE cylinder stud's and nut's.
APE valve spring's.
APE Track King clutch.
V/H KZ1000 sidewinder.
3.5x18 laced to a KZ1000 disk hub.
150/60/18 Shinko 006 Podium.
63" wheel base.

Please Log in or Create an account to join the conversation.

650ed
Offline
User

13 Dec 2015 12:48 - 13 Dec 2015 12:49 #702992 by 650ed

Replied by 650ed on topic Mikuni Kogyo Carb identification

DFIGPZ wrote: I do not understand why people think they will not work on o 650 ? Way back in the 80's I did a KZ650 for a customer 720 wiesco kit street cams lightly ported head and a set of 29 Mikuni smoothbores and it ran and idled flawless like 900 rpm and I do not remember doing much to them :S

You may have answered your own question. As you described it, the engine you put them on was not stock. If it had been a stock KZ650 engine you may have had different results. Ed

1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)

Last edit: 13 Dec 2015 12:49 by 650ed.

Please Log in or Create an account to join the conversation.

floivanus
Offline
User

13 Dec 2015 12:49 #702993 by floivanus

Replied by floivanus on topic Mikuni Kogyo Carb identification

zukdave wrote: They can work work on a small motor if you spend the time to tune them.
I think for the avg. home mechanic they can be a pain,
With mine I think my issue is they need larger idle air bleed jets but since I want a more
modern carb. like a flat slide or the CR special so I'm done with them.

That's my feeling on the smoothbores, outdated old tech that is way overpriced, a set of newer sportbike carbs are an upgrade, newer mikuni designs or CR carbs are also. Yet for the money you could piece together an EFI setup and have instant reliable tuning

my bikes; 80kz1000(project), 77 gl1000, 74 h2 (project)
Past; 78 kz1000, 83 kz550
Andrew

Please Log in or Create an account to join the conversation.

650ed
Offline
User

13 Dec 2015 12:53 #702994 by 650ed

Replied by 650ed on topic Mikuni Kogyo Carb identification

Rendering Error in layout Message/Item: Kunena\Forum\Libraries\BBCode\KunenaBBCodeLibrary::renderEbayLayout(): Argument #1 ($ItemID) must be of type int, string given, called in /home/kzride5/public_html/libraries/kunena/src/BBCode/KunenaBBCode.php on line 314. Please enable debug mode for more information.

Please Log in or Create an account to join the conversation.

kawasakisubaru
Topic Author
Offline
User

13 Dec 2015 13:01 #702996 by kawasakisubaru

Replied by kawasakisubaru on topic Mikuni Kogyo Carb identification

Thanks for all this info, I'm learning a shit ton about these carbs/how they work and it seems the most cost effective plan as of now is to buy larger main jets and pilot jets. Assuming factory jets, what sizes would I need to smooth out the idle?

(Good gas mileage would be nice but fuck it, I didn't buy a motorcycle 11 years older than myself to be economical)

1980 KZ750 E1
Kerker by Kawasaki 4-1 exhaust
Lockhart oil cooler
Mikuni VM29 smoothbore carbs
Pingel high flow petcock
Dunlop K70s

Custom brat style seat
Clubman bars
Dime city cycles 1.5in tach/speedo
Ox blood grips

Please Log in or Create an account to join the conversation.

zukdave
Offline
User

13 Dec 2015 13:18 #703002 by zukdave

Replied by zukdave on topic Mikuni Kogyo Carb identification

Try this page.

www.sudco.com/Diagrams323728/expvm29.gif

Please Log in or Create an account to join the conversation.

floivanus
Offline
User

13 Dec 2015 13:38 #703007 by floivanus

Replied by floivanus on topic Mikuni Kogyo Carb identification

Please Log in or Create an account to join the conversation.

750Kruzer
Offline
User

13 Dec 2015 14:05 - 13 Dec 2015 14:07 #703012 by 750Kruzer

Replied by 750Kruzer on topic Mikuni Kogyo Carb identification

What does the "BS" & "CV" designations stand for?

floivanus wrote: Honestly, I don't really understand the hype, back in the 70's when they came out the 29s were a great carb. Today, there are very few bikes that come with mechanical carburetors, CV carbs dominate the market, even on crotch rockets etc. well, that is, before EFI.

$600 seems to be real world top dollar for smoothbores. Someone once in a while may get more, but it's not typical

1983 KZ750 LTD Twin K1

Last edit: 13 Dec 2015 14:07 by 750Kruzer.

Please Log in or Create an account to join the conversation.

650ed
Offline
User

13 Dec 2015 14:06 - 13 Dec 2015 14:07 #703013 by 650ed

Replied by 650ed on topic Mikuni Kogyo Carb identification

floivanus wrote: "Seems $500-600 is the midrange for them."

Agree. Ed

1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)

Last edit: 13 Dec 2015 14:07 by 650ed.

Please Log in or Create an account to join the conversation.

floivanus
Offline
User

13 Dec 2015 14:17 #703016 by floivanus

Replied by floivanus on topic Mikuni Kogyo Carb identification

CV carbs are controlled by vacuum signal from the engine, they work much like the old quadrajet or edelbrock carbs.
You may crank the theottle wide open, but if the engine only needs 3/4 throttle the slide only really moves 3/4 of the way, reducing bogging, increasing gas mileage and performance. If you look at motorcycles, minus the aftermarket performance carbs, the mechanical slide type carbs basically disapeared in the 1980s and were replaced with CV carbs.

BS carbs are a subset of mikuni carbs that came on KZ and GS suzuki models. I.e; BS34 carbs on kz1000s after 1981.

my bikes; 80kz1000(project), 77 gl1000, 74 h2 (project)
Past; 78 kz1000, 83 kz550
Andrew

The following user(s) said Thank You: 750Kruzer

Please Log in or Create an account to join the conversation.

Nessism
Offline
Sustaining Member

13 Dec 2015 14:19 - 13 Dec 2015 14:20 #703017 by Nessism

Replied by Nessism on topic Mikuni Kogyo Carb identification

750Kruzer wrote: What does the "BS" & "CV" designations stand for?

CV = constant vacuum.

BS is Mikuni's designation for a family of CV carbs from back in the KZ era. BS34's for example are 34mm CV carbs.

Edit: looks like two of us posted at the same time. :side:

Ed
Carb O-ring Kits : www.kzrider.com/forum/3-carburetor/61807...-o-ring-kits?start=0

www.kzrider.com/forum/faq-wiki/618026-new-owner-things-to-know

1981 KZ750E2
www.kzrider.com/forum/11-projects/604901...z750e-project-thread

Last edit: 13 Dec 2015 14:20 by Nessism.

The following user(s) said Thank You: 750Kruzer

Please Log in or Create an account to join the conversation.

Mikuni Kogyo Carb identification

Forum Links