I need help!!

CrownCarbon · Jan 18, 2017

So I have a 1979 XS650, kick start only, stock carbs(bs34) w/ pod filters, stock exhaust and a brand new pamco and e-advance.

I bought the bike and rebuilt the wire harness(it was a rats nest before) worked great was running. but all of a sudden it would die if I let go of the throttle to slow down. Apparently I was on 1 cylinder, from what a neighbor told me. So I checked the points and one wouldn't lift, so I bought part#14-0910 from mikes xs and installed it. At this point I was only able to start the bike if the choke was on, throttle at like 25% and it would start 3/10 times on a good day. I pulled the carbs and the are were clean but had no mixture screws so I bought those and put them in with a 3.5 turns out like I've read. Now the bike wont start at all and has a mean kick back most of the time, I've moved(timed) the pamco back and forth to see if the kick back will stop but no luck. There is no electrical problems from what I have checked and with a new battery that is on 11.something volts during my attempts to turn it over.

650Skull · Jan 19, 2017

Don't buy gear to fix a problem.........Diagnose then buy.

What type of charging system are you running ?

An original charging system has to be charging properly, (go to Tech Menu- Electrical and read threads for charging system), and the battery has to hold a full charge. If this is not happening then these bikes can have the symptoms you are describing.

Really strange for a bike to run without mixture screws...........if the bike was running before you installed the screws then jetting and needle clip would have had to be way off for it to run. 79F/SF usually had BS38's and later Specials BS34's An easy change but confirmation would help

Multiple problems. Fix one at a time. Need to diagnose your charging system. Get your battery tested and replace if necessary.
make sure you have isolated the new Pamco system with a 7.5amp fuse and do not run the bike, (key on), without the plugs or leads earthed

CrownCarbon · Jan 19, 2017

I would assume it's the stock 79' charging system(I know for sure it's it's not pma)

I will look at the system when I get home and go through what I've read and will get back to you.
I'm sure the carbs are BS34's because that's how I found out the mixture screws were missing.

littlebill31 · Jan 19, 2017

BS38 have mix screws too, but they are inserted horizontally.

https://www.mikesxs.net/pdf/XS_Model_ID_Chart.pdf

CrownCarbon · Jan 19, 2017

littlebill31 said:
BS38 have mix screws too, but they are inserted horizontally.

That's how I figured mine were BS34's, mine are vertical like the pdf

weekendrider · Jan 19, 2017

There was nothing in the mix screw holes? Just an open hole?

5twins · Jan 19, 2017

They're probably still sitting on the last owner's work bench, lol.

650Skull · Jan 19, 2017

There were 3 models in 79. 79F Standard........79SF Special, 79SII Special. Models run through 2 years, from around Aug one year to July the next. production date does not mean that is the year of that model. A 79 was produced and sold from Aug 78 to July 79, there can be some discrepancy by a couple of months either side of these dates.

Having BS34's may indicate you have an 80 model and they had some major changes in that year

CrownCarbon · Jan 21, 2017

650Skull said:
There were 3 models in 79. 79F Standard........79SF Special, 79SII Special. Having BS34's may indicate you have an 80 model and they had some major changes in that year

Oh dear lol, now I'm not sure what model it is, I'll have to look more into it later =/

Update- finally got to mess with the bike(stupid jobs) I moved the pamco as far as I can counter clockwise and it stated. Now I can get a timing light and get it right, so I can mess with the those mixture screws.

The pic shows what I had to do to get it to start without braking my ankle!

CrownCarbon · Jan 21, 2017

While I was looking at the bike I was trying to test the charging system and was loosing my mind. I'm going to have to read more into it later but I have a question...

The "Yellow to headlight and starter overrun relays" wire, does that need to be connected to anything? If it's not connected to anything will it cause an issues?

5twins · Jan 21, 2017

It doesn't absolutely have to be connected but it is a good idea to retain the starter and headlight safety relays. The starter one automatically cuts out the starter once the motor starts. The headlight one turns your headlight on. If this is a kick only custom with a separate headlight on-off switch then no need for those relays.

Uhlaf · Jan 23, 2017

Huh, that's the same setting I had. Timing went out of whack, I had to get to work and back. Starting involved a lot of half "feeler" kicks and some gingerly ones hoping the small amount of momentum would send my bike into the ravages of combustion.

It really doesn't take that much force to get an XS going, especially when it's quasi tuned correctly with good ignition.

Paul Sutton · Jan 23, 2017

I have noticed that the XS gives serious kick-back if there is no spark on one side.

CrownCarbon · Apr 3, 2017

so update for future use I guess
I moved the pamco chip towards the top and that seems to be the sweet spot.(I had to unscrew it and move it over to the other pre-drilled holes) Got a mikesxs pma system and the bike is starting with 1-2 kicks maybe 3 on a super cooled morning!! No more kick back either! The carbs seem to be good, I had to tweak those mixture screws little by little (I'm in the process of learning how to sync carbs so they will be on point) other wise I've been riding it around the street and all seems good!
Thanks for the help!!

I need help!!

CrownCarbon

XS650 Member

650Skull

Cockytoo

CrownCarbon

XS650 Member

littlebill31

Smells of Raw Fuel

CrownCarbon

XS650 Member

weekendrider

Iron Horse cowboy

5twins

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650Skull

Cockytoo

CrownCarbon

XS650 Member

CrownCarbon

XS650 Member

5twins

XS650 Guru

Uhlaf

XS650 Addict

Paul Sutton

I Collect Fingers

CrownCarbon

XS650 Member

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