97 Carb Sight Glass

G

G.M.

Well-known member
While waiting for a wheel cylinder I pulled the carb off my 39. I know it's not the correct carb but I like 97's. The drain plug was hard to remove and the threads on the boarder line of stripping. I tapped the drain hole with a 10 100 metric thread that cut in the old threaded drain hole perfect without drilling it out. I wanted to make a simple sight glass that didn't take much room when installed in the carb on the engine. I bought a 10 100 metric bolt 1" long, didn't have many choices. Put it in the lathe and drilled about a .156 hole through the bolt, cut the corners off the hex's so there was still small flats to tighten it with, thinned the top of the head down to about 1/4" and ran a # 10 tape all the way though the drilled hole. Cut the threaded end of the bolt off so I had about 3/8" length of threads under the head. Ran a starter drill in the threaded end to counter sink it good inside of the carb. I took a brass barb splice fitting and turned one end down to the OD of a # 10 screw and cut # 10 threads on the turned end so it had about 1/2" of # 10 threads from the center cutting off the extra. So now I have a barb on one end and a 1/2" of # 10 threads on the other end. Found a copper brake fitting washer that fits the 10 metric bolt to seal under the head to the face of the drain hole. These may also make good seals for the main jet plugs. I will screw the brass barb into the tapped hole in the new plug and push a 1/4" soft yellow plastic fuel tube about 8"s long from Napa over the barb with a soft wire wrapped around it as a clamp and bring the soft tube up the front of the outside of the carb with a clamp to the front screw on the top of the carb to hold it in place. Cut the tube on a 45 angle, long end at the top front and short end at the bottom so any air flow over the top won't put a pressure in the tube. The gas in the carb fuel bowl position will be shown by the height of the fuel in the tube. With good clean threads in the drain hole you could tap a good extra plug for the # 10 barbed fitting or solder a 1/4" OD copper or brass tube in it. I will leave the 10 MM bolt in as the drain plug when I'm done testing and use a # 10 RH brass screw with a # 8 flat washer reamed out a little with some Permatex to seal it. I will try and get some pictures tomorrow. This sight glass will determine and take the guessing out of what's going on with the gas in the carb. G.M.
 
I love it !!v Keep that mind working !They don't wear out near as quick as the rest of the body !! An "inventive mind is a terrible thing to waste" !!
 
I don't know. My mind is having a race with my body to see which one gets to the old folks home first.
 
You have some there skills that I wish I had.. I'm in the need of a fitting that connects the choke tube from the manifold to the choke. If I had your skills id make one like you did and end my hunt ha..ha envious you G.M.
Randy
 
OFA

True, just does not have the right ring to it.
Better fit on a garbage truck.

Bruce

Works good
Lasts long time
 
copied from Van Pelt pages;

Flathead_Carbs_strombg_Fig3.jpg
 

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