The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: coater87 on 21.06. 2015 18:42

Title: bushing choices and dynamo sprocket removal
Post by: coater87 on 21.06. 2015 18:42
 Ok peoples,

 Yesterday I made the unfortunate mistake of boiling my cases with simple green for far too long (family emergency got me distracted) and I blackend my cases. They look like cast iron with a slight purple tinge. I will just shell blast them and make that go away unless someone knows a much easier trick.

 I am cleaning the cases to renew the bushings for cam and crank. I am wondering if there are bushing suppliers I should watch out for. Ones that use the wrong materials or are just bad. The main bush was made by myself out of 660 leaded bronze, but I no longer have the ability to make bushings so I am going to have to buy them. I found a shop that will do the machining, fingers crossed. I just dont want to start bad by buying bad bushings.

 Another question, the dynamo driving sprocket will not come off. It does not look like it is threaded to the shaft but I cannot be positive of that. The shaft and spocket are loose in the casing (sliding in and out) but that sprocket will not budge and I dont want to booger up the shaft. Am I missing something, or being too cautious?

 Thanks guys.
Title: Re: bushing choices and dynamo sprocket removal
Post by: muskrat on 21.06. 2015 21:31
G'day coater87.
You could try vapor blasting the cases.
The sprocket is on a taper. Set it up with a good bearing puller and heat the sprocket. You might have to leave it like that overnight and find it on the floor in the morning.
Title: Re: bushing choices and dynamo sprocket removal
Post by: coater87 on 22.06. 2015 02:51
 Hello muskrat,

 well I really did it with the simple green stuff, cases are dark grey. I tried walnut shells, but even at 120 psi they would not touch it. I sent an e-mail out to a vapor blaster. I know they all use glass beads and thats bad, but with care in final cleaning I should be alright. And the finish you get looks nice and is easier to keep clean I guess.  I will never use simple green on aluminum again, it oxidized it worse than any aluminum I have ever seen. I realize its my fault for letting it go way, way too long- but thats how life sometimes works.

 I got the sprocket off with heat and a puller. Took about an hour and it broke free- thanks for that!