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Posted

Hello everyone

I'm good on this forum (in France, nothing for XS 750!)

Who i am ? Frenchie from Paris - 46 years old

Bikes : XT 500 - XS 650 modified - XS 750 SE

I need help, please:

Bike: XS 750 SE 1979 - Very difficult or impossible to START!

What I did:

- Total renovation of the ramp of 3 carburetors

- Electric wiring redone

- New Candles

- Battery

- Chain distribution changed and tightened

Findings:

- I have a thin blue spark with 3 candles

- The essence runs when I remove the bolts from bottom of tank carburetors

- When I try to start, the starter turns but the engine does not .... I empty the battery

New ideas I had in mind

- Try to adjust the ignition timing but have no timing light?

- I have a ground wire that goes from under the battery to the engine: over again from another large section to the frame?

Please, if you have other avenues, other tests ... all are welcome (In simple English because I am a little French!

Thank you in advance

Regards

Marco

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Posted

marco,

first you need to time the ignition and check contact gaps (if it is contact assisted)

Posted

Hello Drewpy

First : thanks for your answer !

The problem is i've no contacts because is a electronic ignition !!

I've no stroboscopic lamp : is there any truck to check without stroboscopic lamp ??!!

Thanks for your answer

Posted

Hello Drewpy

First : thanks for your answer !

The problem is i've no contacts because is a electronic ignition !!

I've no stroboscopic lamp : is there any truck to check without stroboscopic lamp ??!!

Thanks for your answer

You do really need a strobe light.

Did you set up the valve clearances?

Posted

Hello everyone

I'm good on this forum (in France, nothing for XS 750!)

Who i am ? Frenchie from Paris - 46 years old

Bikes : XT 500 - XS 650 modified - XS 750 SE

I need help, please:

Bike: XS 750 SE 1979 - Very difficult or impossible to START!

What I did:

- Total renovation of the ramp of 3 carburetors

- Electric wiring redone

- New Candles

- Battery

- Chain distribution changed and tightened

Findings:

- I have a thin blue spark with 3 candles

- The essence runs when I remove the bolts from bottom of tank carburetors

- When I try to start, the starter turns but the engine does not .... I empty the battery

New ideas I had in mind

- Try to adjust the ignition timing but have no timing light?

- I have a ground wire that goes from under the battery to the engine: over again from another large section to the frame?

Please, if you have other avenues, other tests ... all are welcome (In simple English because I am a little French!

Thank you in advance

Regards

Marco

Ok I guess the following :-

the starter cranks the motor slowly and the battery discharges quickly (in 1978/9 there was an issue with the electrical system with the XS750SE).

Most problems were caused by the regulator/rectifier going to earth (via the red wire in and the bolts earthing it) or in bad cases the generator also went to earth (shorted for English speaking people). To start the bike add a car battery to the bikes, this will give you the charge in order to start the engine. If the engine then stops within 5 mins you can say the regulator is at fault, but if the car battery fails to start the engine and the starter motor slows down you have a generator problem, but take into account the age of the bike you may have some bad wires and earths so insure every thing is correct before you start

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