Carb Cleaning

I just took the carbs off my 750 Interstate, in the process of restoration. They are amal 932 in case your wondering. What is the best way to clean these things, some sort of carb cleaner? Or is there a better option.

Matt

Solvents don't get the zinc oxide crust out of bowel or jets only mechanical scratching and proper drill/probe for pilot jet works or boiling 10 min in white vinegar to dissolve metal oxides. LIme away might too but keep eye on process.

Amals polish up nice for a few rides.

I would strongly recommend drilling the plug out of the pilot circuit so you have access for proper cleaning. Here is a link to the modification. It can be done at home with a hand drill if you are careful. I have done it to all of my amals.



http://www.jba.bc.ca/Bushmans Carb Tuning.html

NAPA sells B9 Chem Dip, a nasty solvent in a 3/4 gallon pail. It comes with a basket that you put the parts into and "dip it" for a while. This stuff is hard core and will melt rubber or plastic, which fortunately on Amals can all be removed. After doing that once, carbs can be maintained with the standard spray can stuff.

Wear eye protection and nitrile gloves.

Do not fail to true up all sealing surfaces on these carbs and the manifolds as part of your overhaul. You will find that they are not true, due to overtightening by POs or even original factory work. Truing everything will make a noticeable improvement in carb performance, especially at idle. You can do the truing with some 220 followed by a couple passes on 320 wet or dry paper used wet on a piece of 1/4" thick glass or any other absolutely flat surface. IMO, you haven't overhauled the carbs if you don't take this very important step. No matter how good everything else is, if the surfaces that are supposed to seal don't, the carb will not work properly.

Also... on the carb to manifold joint there is an Oring. When you finish truing and install the new Oring, JUST tighten the carb/manifold bolts so they compress the Oring. That's it. Do not crank down on the bolts - it serves no useful purpose and you will just distort the surfaces again. Distorting this part of the carb will also cause the throttle body to warp which can cause the slide to stick. And don't forget the manifold to head heat gaskets. I have found that a very thin smear of Permatex Ultimate grey Moto (same stuff as yamabond, Hondabond, etc, will ensure no leaks on that side of the system. They are hard gaskets so they sometimes don't seal too well to the AL surface of the head or manifold, especially if there are any imperfections in the head or manifold surface. You can true the manifold easily enough on the plate glass but you can't really do anything to the head's intake surface with the head on the engine.

Good Luck

Dave,
Does the Chem Dip get rid of the metal oxide build up in the float bowls like Hobot was talking about?

Matt

I alway boil mine in a water/acetic solution (vinegar)

Philippe

Yeah, toss in some greens and it's great - "Salade Amalie"

http://www.aircooledtech.com/tools-on-t ... a_blaster/
Try this works for me!

That looks pretty darned cool!

maylar said:

NAPA sells B9 Chem Dip, a nasty solvent in a 3/4 gallon pail. It comes with a basket that you put the parts into and "dip it" for a while. This stuff is hard core and will melt rubber or plastic, which fortunately on Amals can all be removed. After doing that once, carbs can be maintained with the standard spray can stuff.

Wear eye protection and nitrile gloves.

Click to expand...

+1 on the Berryman's B9 Chem Dip.

Also, Yamaha Carb Cleaner, Part Number ACC-CARBC-LE-NR. (No Kidding) This stuff works really well also, get an old crock pot and simmer the carbs in this stuff.

boil it in lemon juice

I would go for the homemade soda blaster. It works great and makes them look like new. It removes all the white buildup also. Carb dips used to work many years ago before the EPA got a hold of them. Now they are pretty much useless.

Do not use vinegar as it will make all the brass jets larger. Lemon juice does shine them up some. Jim

Thanks, Comnoz, I've tried the soda blaster previously on a few parts and it worked but not as great as I would have liked. Maybey compressor wasn't big enough. What size compressor do you use and what PSI?

Ultrasonic bath gives great results, just had a few sets done.

The serious nasty chemical cleaners with mild acid pH will dissolve the oxides but its over kill for small Amals and the toxic remander to be rid of.

No two Amals ever the same when actually measured. Most the flange fit issue is not over tightening as always claimed but an innate feature of casting that size object still going by smaller object scaling methods. They are often skewed right out the box I and others have found. Differing thoats, out of round etc. I've given up on the 0-ring as it can't be clamped down on hard enough w/o risking a bow in flange or too loose nuts can't seal air out. I don't like loctite there as makes removable a chore on my attitude. I use thick gasket smeared with about anything and nip it up good and use anti sieze in head threads.

Roundness can be attained by tapping over a round dowel. Worth settting spray tubes same height as practical for similar response L/R though Amal said tested showed it didn't affect mixture ratio.

There is one trick to get more fuel flow at held WOT when its possible the fuel can't enter bowl fast enough and goes lean and power wans. BSA did a mod by cutting a slot out of the bowl side of fuel passage after the float needle seat

I don't understand that BSA modification. How does it increase fuel flow? It seems to me that the inherent restriction is the size of the hole in the seat that the needle bears against plus the height the needle lifts off the seat. Are they saying that not enough fuel can flow around the oem needle/seat and into the bowl to keep adequate fuel at WOT? Is that just a BSA large single cyl engine thing? I have not seen that mod in any of the Norton bulletins.

mattthomas4444 said:

Thanks, Comnoz, I've tried the soda blaster previously on a few parts and it worked but not as great as I would have liked. Maybey compressor wasn't big enough. What size compressor do you use and what PSI?

Click to expand...

With soda I usually end up around 50 PSI. My compressor is 12 horse. I turn it up for the stubborn stuff. It does not remove rust. It will remove paint slowly with no damage to thin metal.
On carbs I use a cheap harbor freight sandblaster kit. Like one that is supposed to feed out of the bag. Then I just use a short feed hose with the smallest nozzle and a bag of soda. Since it is not really set up to do soda I find it plugs the feed hose easily but it is also easy to clean out. There are some kits to make soda work better but I haven't got one yet.

The soda leaves a fine gray finish on the metal. A quick rubdown with fine steel wool leaves them looking like new. Jim

Mike, I think you got it right. Its a "port" job. Just eases the transfer of fuel to the bowl after the float needle/seat barrier.

Relative pressures, as regulated by the relative diameters and lengths of holes/tubes are what carburetors are ALL about. That's true, not just in the venturi/slide area but also in the float bowl; the vent area, the area of the bowl, the float needle design - upside down or rightside up, choke vs enrichener, all of that stuff matters in intuitive and counter-intuitive ways.

I think I will try boiling in vinegar, what sort of proportions between vinegar and water should I use?