Mikuni BS Carb Rebuild

[JAPA]

Hi all. I was looking through the newbie welcome links, and quickly learned that emptying a can of carb clean into every foreseeable hole and crevice doesn't suffice for a rebuild. However, when i went to look at links related to showing the proper way of doing it, i found that the links no longer work!! Is there anyone who has alternative resources?

Post edit: where are the mixture screws??? after poring through diagrams the only adjustable screw on this siamesed carb is the idle adjustment screw. there ARE two screws on the sides, but they seem like just empty holes. the screws stay loose if not completely tightened anyways.

 

[Rich82GS750TZ]

There are 2 good CV (BS) carb rebuild tutorials on BikeCliffs Website. Right margin, At the top, under Other Contributors: both links work

 

[Big T]

There are some links on the welcome page that are broken
Click on the BassCliff website and you'll find what you need

 

[steve murdoch]

CV Carb tutorial.
http://zeus.mtsac.edu/~cliff/storage/gs/Mikuni_BS-CV_Carburetor_Rebuild_Tutorial.pdf

 

[JAPA]

CV Carb tutorial.
http://zeus.mtsac.edu/~cliff/storage/gs/Mikuni_BS-CV_Carburetor_Rebuild_Tutorial.pdf

thanks for the guide steve, even though my carb is not too similiar to that one, the details of the teardown and clean will be similiar right?

 

[Steve]

Yes, the details are similar. Well, let's just say the principles are the same, the details will be a little different.

I have rebuilt several sets of your BSW30 carbs with at least modest success.

Not sure if you have Berryman's Carb Cleaner Dip available in your area, but it's the best way to soak your carbs. Just ignore the instructions on the label. The instructions say to soak parts for 15 to 30 minutes. They were probably written when the chemicals inside could do the job the way they are written. It is recommended to soak for 15 to 30 HOURS, then rinse in HOT water. Follow that with a brief spritz of carb cleaner through all the orifices (back flushing is best), then dry with a blast of compressed air.

.

 

[Kiwi Canuck]

I don't think Berrymans is available in Canada so I bought some in Bellingham, it works OK but as Steve suggested it takes a while, never found it be be that effective.

Instead I now use an ultrasonic cleaner and it works awesome, just watch what chemicals you use as anything too caustic will damage the carb body if left in too long. (or darken it)

Use distilled water and a little degreaser, Simple Green Pro is better than standard simple green, I use another product from USA, Frank's Special Degreaser, mixed about 40:1 it works well and no issue with the carbs discolouring.

David

 

[Guest]

I don't think Berrymans is available in Canada so I bought some in Bellingham, it works OK but as Steve suggested it takes a while, never found it be be that effective.

Instead I now use an ultrasonic cleaner and it works awesome, just watch what chemicals you use as anything too caustic will damage the carb body if left in too long. (or darken it)

Use distilled water and a little degreaser, Simple Green Pro is better than standard simple green, I use another product from USA, Frank's Special Degreaser, mixed about 40:1 it works well and no issue with the carbs discolouring.

David

Is ultrasonic cleaners as magical as they sound? Can I use it to wash everything, bit by bit? And make it clean as new?

 

[Kiwi Canuck]

They are awesome, but it takes a while to figure out the secret sauce, most people will not disclose their concoction who charge for carb rebuilds but there is a good thread on here about buying and using ultrasonic cleaners.

I always pre-clean whatever I put into the unit so I don't contaminate the cleaning products too quickly, especially carbs.

I bought a 3 litre unit but should have bought the 6 or 10 litre unit, I get 1 carb at a time and I need to flip it a few times during the cleaning.

I give each carb 3 timed cycles of 20 minutes each at 50 degrees Celsius, that is usually enough.

For the jets if they are blocked I put them in a ziplock plastic bag with carb cleaner and submerge them and give them a few cycles, it usually softens up the gunk enough to clear them out with compressed air.

Here's a sample of a before and after from a while back while rebuilding my GS1000S

David.