TX, SX650, KZ750, Carburetor Diaphragm Mikuni BS38, BS34 SS, BS32

27 Jan 2015 | Author: | Comments Off on TX, SX650, KZ750, Carburetor Diaphragm Mikuni BS38, BS34 SS, BS32
Yamaha TX 650
Yamaha TX 650

N ew carburetor diaphragms for the MIKUNI BS38 CV * Carburetor used on Yamaha 650 vertical twins. These are CV* ( constant velocity ) carbs used from 1970 till

1980. 77 mm OD of diaphragm groove. Does NOT fit the carbs used from 1980 on. You must use BS34CV diaphragms ( 73 mm OD ) if your bike was made in 1980 till end

of production. C heck your diaphragm groove diameter.

Cracked worn or torn diaphragms can allow imbalance to carburetors causing one cylinder to work harder than the other.

This diaphragm set does NOT include new throttle slides. This is a easily installed rubber part that goes on your old slide. The rubber is attached to the slide by pushing the thick

section over the swagged lip that held the plastic washers. The thick section of rubber grips the slide and replaces the plastic washers. The pictures should explain how this

works. Please print these instructions.

A quick mail to say that the M-77 fit BS36’s on an ’83 Suzuki GR650 Tempter.

Your diaphragms work great. I have about 2K on these so far and so far so good. XS400

Regards, Waldo

Hi Don,

I just wanted to provide you some feedback on your products…they work great! I installed them on my ‘81 Yamaha XS400 with BS34CV carbs. They went on easy, and the bike

ran like new. The bike went from almost non-running to tearing up the neighborhood in less than an hour.

Thanks for the great product and fast delivery,



Just wanted to say that I received the diaphragms and that they were absolutely great!

Allthough the old diaphragms didn’t have any holes in them, replacement improved performance dramatically.

Best money I’ve spent in a long time, great value, thanks for making such a product available!

Best regards,

Oeyvind Elbert

Hagaveien 15b

1387 Asker


I just received the new BS38 diaphragms, and am extremely happy. Very nice work, and I can’t thank you enough for saving the carbs on my 79 XS.

Thanks a million!

Norm McRae

Just to say diaphragms arrived on friday 21st, I fitted them today 22nd, they fitted perfectly and very straight forwardly. Ballanced carbs. one very happy FJ 1200. Regards

Graham. Northumberland, England.

Great alternative to $300 NOS slides. Works as advertised.

Buyer: wch69sooner2010 ( 3 ) Apr-09-10

YAMAHA XS, TX 650 Mikuni BS38 CV Carburetor Diaphragms (#230435468325)

As Usual. PERFECT.

Buyer: spydercycleworks ( 3184) Mar-31-10

YAMAHA XS, TX 650 Mikuni BS38 CV Carburetor Diaphragms (#330413174303)

Super quick, great product and seller! Thanks Don

Buyer: bluebikerblan ( 57) Mar-24-10

Yamaha XS 650 Carburetor Holder Socket Boots USA made (#330411790711)

Item worked great and quick delivery very pleased

Buyer: gerald.423 ( 4 ) Sep-14-09

YAMAHA XS, TX 650 Mikuni BS38 CV Carburetor Diaphragms (#330355707704)

Thank you. Very cheap shipping A+ Good part at a super price wish I had got more

Buyer: jeremyb977 ( 26) Jul-09-09

YAMAHA XS, TX 650 Mikuni BS38 CV Carburetor Diaphragms (#230348064346)

Worked like a charm. I wasn’t sure if I’d ever be able to find this part again.

Buyer: shadowstep07 ( 20) Jun-22-09

What a great product. 15 mins to install, bike running like a dream again. A++++

Buyer: izibead2012 ( 28) Feb-16-13

YAMAHA Diaphragm SR250 XS650 XJ400 XJ1100 XJ900

Buyer: 970_anchondo ( 18) Sep-03-09

sven spicker

Just wanted to say thanks.

The diaphragms arrived yesterday, were put in today and I couldn’t be happier with the results.


Thank You.

John M. Wright

388 Painter Street

Rio Dell, CA. 95562-1432

I have just installed M-70 diaphragms on my Mikuni BS 33 carburetors from a 1985 Yamaha Maxim X XJ700XN. The parts fit perfectly, installed easily and operate

flawlessly. This diaphragm will also work on models XJ700XNC from 85′ as well as the 86′ models XJ700XS and XJ700XSC. (the only two years these models were

made as far as I know) so please add these to your list of bikes these diaphragms will fit as it may help some poor soul trying to locate these rare and hard to find parts.

or paying $180 per slide and diaphragm assembly (which there are four on these bikes). Thank you for an excellent part at a fair and honest price and prompt delivery

(2 days). I hope this helps someone find a part that they are looking for. Thanks again! Randall Edwards

These diaphragms are easy to install and restore XS650 carbies BRILLIANTLY. Buyer: Member id laoshi50 ( Feedback Score Of 304) Apr-12-11 03:20

YAMAHA XS, TX 650 Mikuni BS38 Carburetor Diaphragm 77mm (#330543642298)

Test drive was awesome! Great diaphragms, huge performance difference! Thanks Buyer: Member id 1105sunnylake ( Feedback Score Of 1 ) Apr-22-11 06:52

Diaphragm KZ700/750/1000/1100 VS-750 MIKUNI BS34SS 70mm (#230598414002)

RE: XJ900F BS36CV . -Thanks for the delivery. I installed the diaphragms and they work like a charm. My bike has full power again and is running great.

Regards, Henry.

Thanks for the BS34CV73mm diaphragms. I have fitted one to my Yamaha SR250SE 1981 and it works a treat, the old diaphragm had a total of 5 holes in it!

Richard Warner.

I purchased a pair of diaphragms for 35mm Mikuni s for my 1980 XS650 a while back, which have been fantastic, not a problem.

I live in Newcastle, Australia

Quick message to let you know BS38 diaphragms fit yamaha XS500 fitted with Mikuni BS38 CV carbs. fitted a treat.

Hi Don, RE: XJ900F BS36CV That was fast – I got the parts this morning installed them

already. Work fine. Thanks for the fast service. Rgds, Chris.


the replacement Carburetor Diaphragm came it today.The quality of these parts is perfect and

better than the original in my opinion.

I am working on Motorcycles since 1979 and was happy to get these high quality spareparts.

Thank you very much for your kindful help and assistance and the fast delivery

Berlin/Germany WOLF.

Hi Don,

Thank you for your speedy reply. Payment sent via PayPal.

PS. I just returned from a 1,000 mile round trip after installing the new BS34 set I borrowed from a good friend and they performed excellently I was very pleased.

Ben Bennink

I need 4 BS34 diaphrams. These will fit the 1980 Yamaha XS1100 SG (Special) that I’m rebuilding. Thank you for your time. — Also the set I bought for my 1979 Yamaha XS1100

SF (special) work perfectly. Thank you for a great product.

Peter Albers


I now have used several of your Diaphragms for the CB360, CB350 and KZ440 I have found them easy to install and they work VERY WELL .


G’day Donald,

I received the diaphragms not this week, but last. I was waiting for my dad to pick them up and have a look as they are for his TX750. He is very happy with them. Your service has

been excellent and would not hesitate in dealing with you again.

Regards and best wishes, Tony Oxenbridge.

* Constant velocity carburetors actuate the throttle slide and needle at anything over a fast idle. The atmospheric depression or vacuum caused by the venturi of the

cut-away is used to raise the slide by means of the vacuum on the top of the diaphragm. ( There is a communication hole to the venturi in the throttle slide.)

Made in USA on limited basis with high quality rubber.

Reasonable shipping worldwide!

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