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Discussion Starter · #1 ·
First off I would like to say hello! My name is Cole and this is my first post. I am new to the world of brit bikes (owned and repaired dozens of jap/harleys), and I was sent to this forum by several people that said its "the place to be". Well, the first thing I did was look through the tech section so I wouldn't ask any "newbie" questions, but I am sure I will anyway (I apologize in advance). I got my new 650 chop home, and I have a few questions:

1. I would like to do a compression test on the engine and needs to know a few things. What are good compression numbers for one of these engines? How many time do I need to kick it through to get an accurate result (never owned a kick only bike).

2. I cleaned up the 930 Amal carb, but I need a new fuel banjo before I can do anything with it. I noticed that it had a 190 main jet in it, but most places I look say that is the size jet that dual carb setup's use, and that a single carb setup would have a 230 or 240 main??? That seems HUGE to me, but what do I know. Also, should a put time into getting the Amal going, or should I just buy a PWK setup from Lowbrow customs.

3. This bike still has the points setup, should I get it running with this setup first or should I just get an electronic ignition setup???

4. The bikes wiring is a nightmare and I would like to wire it from scratch, anybody got a diagram for simple wiring that will work for one of these???

I looked in the tech section but noticed that the few diagrams that were brit bike specific are no longer there (images deleted). I am looking for a diagram that I can follow exactly for my dual coil, points, positive ground setup, or a diagram that shows me exactly how to rewire it as negative ground setup... I am an electronic moron, but I can follow directions.

Any ideas/help is appreciated. I hate to do things twice so I like to ask a lot of questions to ensure I am only spending time/money once Lets hear your thoughts guys and gals......

BTW... here's a few pics of the bike (bought from the original owner who chopped it in 1969). Oh, and that is not rust on the springer springs, it's paint.




 

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First step is to get a manual. All the jetting, wiring and other information will be there.
As far as not wanting to do things twice, well, better get used to it. BSAs are great bikes but there's a lot to learn.

If it has a 190 main jet, see how it runs and then jet up or down accordingly.

Nothing wrong with an Amal, buy a new Amal if yours is in bad shape (worn slide/bore).

Nothing wrong with points, but electronic is probably the best route. You'll probably need to replace the 12V coils with 6V if you go to electronic, or use a single dual lead coil.

I wouldn't worry too much about the compression. If it runs good and doesn't oil the plugs the compression is probably okay. If it runs poorly and oils the plugs you'll have to rebuild the top end.

First place to start? A proper tune-up: set the timing, check the valves, clean the carb, etc.
The manual is very important! Set everything exactly as it says, including spark plug gap, etc. (You can use more gap with an electronic ignition.) There are no short-cuts here, everything has to be checked and it all has to be right.

No need for gaskets on the valve cover or other covers, use Yamabond or other semi-hardening sealer (just a thin film).

Have fun!
 

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re the jet(s) I've gone as far as a 240 when everyone/manual said that was way too big.
Keep tweaking the carb step by step and record everything.
Pay attention to what the plugs and power delivery are telling you and you'll get there.
That's what I/ve learnt and it worked for me.
Allthe best.
 

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Discussion Starter · #6 ·
I found two diagrams but neither one of them are for a system with a battery, points, and dual coils. What would I change in these diagrams to make them work for my system?



 

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Discussion Starter · #7 ·
I think I found what I need... A diagram for a positive ground, dual coil, points ignition with a battery! Does this look good to go off of?

 

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that second Lowbrow diagram showing a Boyer ignition does not show any ground for the positive side of the battery or Podtronics unit. I would change that if it was me.
 

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That is one sweet BSA chopper. You did very well in finding that...good for you.

M.A.P. Cycles had the wiring diagram you seek in their printed catalog but I don't know if it is on their website.

British Only and British Cycle Supply have tech sections with wiring diagrams as well and check Rask Cycle too.

A google search for chopper wiring diagram may be sufficient. Good luck :cool:
 
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