I am trying to get a '78 xs400 running again. What is the bare minimum I need to get this running electrical wise? I don't plan on using the electric starter and believe it is dead anyway. Also, the right handlebar switch has been cut. What wires need to be switched together for the starter? The Red/White and Brown? Also, what as far as safety switches are there that would preven spark? I can get 12v to the coils by switching the red/white and brown on the right handle switch harness together. I have them on a switch. But i don't seem to be getting any spark. Thanks.

UPDATE:

Checked the coils today. Both are within range for the Primary and Secondary Coils(Lf: 3.8pri 9.6ksec Rt: 4.3pri 9.56ksec). I will be checking gap on the points tomorrow and putting in new plug caps and plugs.

I am trying to get a '78 xs400 running again. What is the bare minimum I need to get this running electrical wise? I don't plan on using the electric starter and believe it is dead anyway. Also, the right handlebar switch has been cut. What wires need to be switched together for the starter? The Red/White and Brown? Also, what as far as safety switches are there that would preven spark? I can get 12v to the coils by switching the red/white and brown on the right handle switch harness together. I have them on a switch. But i don't seem to be getting any spark. Thanks.

Hi,

The minimum you need to get a spark are the following :-

Charged 12v battery

an on/off switch

wiring to supply 12v to coils

wiring to ensure the C/B points & condenser is in circut.

but using the original loom & switches (assuming the wires to the points etc are sound) in the R/H switch you only need to insure that the kill switch is working, the starter button wiring plays no part at all.

It would appear you have the voltage to the coils but not to the points etc which indicates the kill switch but I guess you have checked the fuses and statically checked that the ignition timming is correct or close. Without more info on the model (UK, US etc) I cannot find the correct diagram in order to give you a walk thro.

Regards Jim

Hi,

The minimum you need to get a spark are the following :-

Charged 12v battery

an on/off switch

wiring to supply 12v to coils

wiring to ensure the C/B points & condenser is in circut.

but using the original loom & switches (assuming the wires to the points etc are sound) in the R/H switch you only need to insure that the kill switch is working, the starter button wiring plays no part at all.

It would appear you have the voltage to the coils but not to the points etc which indicates the kill switch but I guess you have checked the fuses and statically checked that the ignition timming is correct or close. Without more info on the model (UK, US etc) I cannot find the correct diagram in order to give you a walk thro.

Regards Jim

I meant what is the correct wiring for a kill switch? Not starter. Also, it's a 1978 U.S. model. Points ignition and 2 coils. Not sure how to tell difference between the E model and the 2E model. Also, is there a way to check the condenser?

I meant what is the correct wiring for a kill switch? Not starter. Also, it's a 1978 U.S. model. Points ignition and 2 coils. Not sure how to tell difference between the E model and the 2E model. Also, is there a way to check the condenser?

Hi,

yes there is a way to test the condenser ... it should read 0.22 microfarads (or was it 22 microfarads .. its an age thing but the condenser has it written on it) across the live wires & earth, then if you have the tool to charge it up you can 'shock' ur mates (not recomended but it was fun when at collage etc). But tbh I'm putting the money on the wiring being so ratty that the voltages are not being supplied to the correct items.... I'll build you a wiring list based on a UK diagram then you will have to work out the odd difference between the 2 versions

Regards Jim

Hi,

yes there is a way to test the condenser ... it should read 0.22 microfarads (or was it 22 microfarads .. its an age thing but the condenser has it written on it) across the live wires & earth, then if you have the tool to charge it up you can 'shock' ur mates (not recomended but it was fun when at collage etc). But tbh I'm putting the money on the wiring being so ratty that the voltages are not being supplied to the correct items.... I'll build you a wiring list based on a UK diagram then you will have to work out the odd difference between the 2 versions

Regards Jim

well i have redone the fuse box already with blade fuses and all new connectors and seem to be getting voltage where it needs to be. But i need to know if i am wiring the kill switch correctly by hooking the red/white and brown wire at the right handlebar switch harness.

well i have redone the fuse box already with blade fuses and all new connectors and seem to be getting voltage where it needs to be. But i need to know if i am wiring the kill switch correctly by hooking the red/white and brown wire at the right handlebar switch harness.

Just thought .... is the main switch still in circut ?

Regards Jim

Main switch that works off the key? Yes, it is hooked up and functions correctly.

UPDATE: Got fire today. I put a switch on the right handlebar switch harness between the red/white and brown wire which gave me power to my coils. I also put new plug caps on my plug wires and tested by making the points contact with a insulated screwdriver to simulate engine rotation. Seem to be getting good fire to both cylinders. I was even able to get a few "pop offs" with ether. Ran for a second off the ether and died. Pulled the carbs and will be cleaning them this weekend. This project is coming along nicely. My plans are to turn it into a kick-start only cafe racer in the end.

UPDATE: Got fire today. I put a switch on the right handlebar switch harness between the red/white and brown wire which gave me power to my coils. I also put new plug caps on my plug wires and tested by making the points contact with a insulated screwdriver to simulate engine rotation. Seem to be getting good fire to both cylinders. I was even able to get a few "pop offs" with ether. Ran for a second off the ether and died. Pulled the carbs and will be cleaning them this weekend. This project is coming along nicely. My plans are to turn it into a kick-start only cafe racer in the end.

Hi,

I guess the timing is still out ... cleaning the carbs out will be a good thing .. and just go back to the timing issue !

Regards Jim

Hi,

I guess the timing is still out ... cleaning the carbs out will be a good thing .. and just go back to the timing issue !

Regards Jim

No, I think the timing is good. I ran it for a second off of only ether, no gas to the carbs. I know they are gummed up. So now I should just have to clean the carbs and it should run.