Your Carbs NEED to go CLUNK!!!

why don't my Hatachi carbs have brass pistons ? either set

 

I think some of the Pistons are Teflon Coated.

I'm not too sure about what the coating is ... but, they are coated.
There is also some texture to the coating. A fine texture; but there.
I think that helps them glide when everything is working perfectly.

 

Nev-R-Dull is COOL STUFF it's been around since the 50's my Grandma used to use it on silver. I thought it was long gone but then discovered it at the auto parts. It's a NON-abrasive polish, and it does work quite well. Be aware that part of its "magic" is an oily wax that it leaves behind, great for some things (like chrome) not so good for others...

 

maybe yours are brass but mine are anodized aluminum and you for sure don't want to take the anodize off

 

ok you got me I just happen to have my carbs apart for larger mains and new shaft seals so I did the clunk test all 4 sound good and the bores look almost new but not polishedso I know what I'm doing tomarow
-excelent write up Rick I think I may go buy stock in polishing compounds now :lol:

 

If you do the work and bring the Bores to a brilliant polish ... when you wrist-on the power ... the Diaphragms are going to OPEN and get you moving on Main Jet Fuel ... right-quick!

Shut the Throttles and they Slam Shut ... braking line a Fuel Injected mill.

 

Thanks for the info Rick. I'll be doing my carbs this winter.

 

Since that article was published, here, I have found a MUCH easier way to deal with Diaphragm Piston Bores.

Dremel Tool.
Flexible Wand Extension.
Sanding Barrel Bit.

I remove the Rubber Barrel and substitute seven (7) ScotchBrite Pad 19mm Discs.

I make the Discs myself.
Using a 19mm Socket which I have GRINDED both the Inside and Outside Diameter of its opening to a Cutting Edge, ... I used the 19mm Socket "Cookie Cutter" to fabricate perfect 19mm Shining Discs.

I mount 7 circular Discs on the Bit using additional hardware to keep the Discs from freewheeling.
I arrange the Discs on the Nit like this:

Bit Shaft>Flat Washer>External Star Washer> 7 Discs > External Star Washer>Flat Washer>End Securing Screw.

Its a tight fit.
The Discs look like a Ball once fitted.
ScotchBrite GRAY will remove the glaze and shine the Cylinder.
ScotchBrite WHITE will apply a crude finished surface.

Dremel Buffing Pads and No.'s 5 & 6 Jewelers Rouge's will put a Mirror Finish on the Bore and will get you writin' home to momma!

 

does this "maintenance" work on all carbs? on all bikes?

 

On ALL Bikes having Constant Velocity-type Diaphragm Piston Carbs.

Either Hitachi -or- Mikuni

The Bore gets Oxidized after the passage of time and particularly if the Bike "Sat" for an extended period.

Routinely done by Racers as an element of "Special Tuning"

 

more specific then...a '76 GL1000

 

The Carbs on that Honda have two areas that need to have as fine a finish on them as you can apply.

The Bore:
Where the Vacuum Piston travels within the Body of the Carb.

The Upper Body Outer:
The Outside surface of the Vacuum Pistons "Moving Part"

The Dashpot Inner:
The Inside Diameter of the Dome that fits over the Vacuum Piston Assy.

You have to be able to reach in the Carb and lift the Piston and feel for smooth and free movement up and down.

 

Only one of of my 4 close like a slammed in the wind door ... the other 3 close like a creaky coffin lid!

Just had the carbs off several times, but this sounds a worthwhile reason to take 'em off again as the sticking means the revs stay up too long when you throttle down.

Cheers for another inspirational thread Rick

 

I've got mine all apart right now and thought they were good. I started reassembling them last night and realized that two of the four were falling like a rock, until about the last quarter inch or so of the bore. Looks like I get to polish those again. My bike hasn't run in over 6 years, I've only had it for about 5 months piecing it back together so I want to make sure this thing is running to it's full potential when I get back on the road.

 

Hi Rick,
I was rereading your posts and have a question to throw out there. The pistons on my 82 xj650 have a micro etching on them like very small rings running around the outside. I think these rings help hold a small amount of fuel between the piston and the carb bore for the purpose of lubricating the piston. Would polishing the piston not remove those etchings and cause the piston to stop retaining the nessesary fuel between it and the bore?

Thanks,
James

 

Don't Polish the Poston.
Re-finish and Polish the Carb Body Bore.

The Diaphragm Pistons for some Bikes have Pistons that have something like a Teflon Coating.
That you just clean.

The Pistons which are NOT coated can be Cleaned and Polished.
But, I have not found a product to use on them that will remove the "Smile" on the Piston where it it exposed to the Throttle Plate opening.

 

Can you post a photo of the polishing tool you used to polish the bores?

 

Dremel
Flex Extention Wand Attachment
Dremel Buffing Wheel

http://cgi.ebay.com/ROTARY-GRINDER-TOOL ... 3a5924547a

 

Can you effectively gauge the clunk if the carbs are fully assembled? Or do you need to pop the hat, remove the springe, and unseat the diaphragm?

 

Hey guys
Was just looking at stuff on the Maximum Suzuki forum and found this little piece on cleaning carbs with Pine Sol. Here's the link: http://www.cb750c.com/modules.php?name= ... 66&start=0
I've seen the posts about using Ultra Sonic equipment, but unless you have the money for a big unit the carbs have to be seperated . This way all you need to do is get a big plastic tub, fill it with Pine Sol and you're good to go. One guy uses an orbital sander as a poor mans Ultra Sonic but he's not sure if it helped.