Need help with my Boyer?...I think

[mjaw001]

I have a 1978 xs650 that I have turned into a bobber. The motor ran before the deconstruction and had a Boyer ignition installed along with all the original condensors, regulators, etc..

I have now added the modern regulator/rectifier, and I'm trying to set the timing on it but I'm not sure if I have the motor lined up to the "full advance" mark on my timing tab like its says I'm supposed to do on the Boyer website. I have attached a picture with a red arrow showing where i think it is.

If I am right with my timing then something else must be wrong because it simply will not start. It has only kickstart and every 2nd or 3rd kick it gives a loud backfire and never actually starts.
I have cleaned out the carbs and charged the battery but still no luck.
I have fuel going to the carbs and I do have a spark at the plug.
I keep reading about nylon screws but as you can see in the picture i don't have any of those, is this my problem? Do i need nylon screws because I have changed over to the modern reg/rect?

Please help! Its summer and I want to ride![/SIZE]

 

[Bigzakdaddy]

I got a couple questions and then a couple suggestions...

1. Before you bobbed or chopped, the bike ran Perfectly?

2. Did you mess with the timing during the build?

3. Did you rebuild the carbs or clean them before reinstall? Or when the problems started?

4. What is your wiring like? Meaning, is it a nest or perfectly laid out and all connections clean?

5. Did you remove the disc behind your points cover during build?

All little more info might help others chime in!!

If you didn't mess with the timing or the carbs during the build, it's most likely a wiring issue that's causing your pain.

Check out curlys charging system guide in the tech section. Alot of great tests to do to help you determine that your bike is charging correctly once it's running.

Im not positive about the nylon screw issue, but, know that in your picture, one of your brushes appears to be out of wack!! That would most definitely cause a no charge problem.

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[mjaw001]

Before I bobbed it the bike ran but it had a bent crank, so I put in a different bottom end. So maybe I have to change something in my bottom end to make it jive with the original boyer in the top end?
The timing has been messed with since the whole motor has be completely taken apart.
I cleaned out the carbs after I had this problem, think that would fix it.
And my wiring is simpified, nice and neat, very confident about that.

thanks for the replies!

 

[retiredgentleman]

The red arrow is at the timing position for idle, about 15 degrees. The yellow arrow is the fully advanced position, about 40 degrees.

 

[Bigzakdaddy]

Ok, so that makes a little sense. Seems you've had it all totally apart!! I was under the impression that it was just a cosmetic build. Did you mess with the digital advance disc when apart?

If I were in your shoes, I'd:

Set the timing per retired gentlemans pic, try adjusting the advance as you try to start the bike. My bike was in a position like yours when I first installed my Boyer. Adjusting my advance got it running enough to start tweaking and testing. Are your valves adjusted, cam chain set properly?

Hope all of this helps...

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[mjaw001]

Thanks for all the great advice!
I also have another important piece of info, the bottom end is off another bike, so that would explain why its not jiving with my top end.
Ill try setting my timing to the yellow mark and see if that works.
As for the nylon screws anyone know if I need them for this setup??

 

[Bigzakdaddy]

Was it a different year? Did you use your original rotor alternator stator assembly? Or the donor stuff?

I did not use the nylon screws for my set up. I think certain years required you to unground the stator. Was the bike charging before? Regardless, they wouldn't keep the bike from running.

Have you adjusted your advance?

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[mjaw001]

Unfortunately I used the donor stuff and I don't know what year it was but ill check the vin # in the morning and find out the exact year.
I will adjust the advance in the morning to yellow marks as shown above hopefully it will actually start this time. Will post back tomorrow with results.

Thank again!

 

[mjaw001]

Yayyy!! Got it running this morning! You were right with the yellow mark on the timing, I was way off. Thanks a bunch, now I just have to fine tune it, get the mixture screws set and jet it properly since I'm running straight pipes.

Cheers!