FED UP, right side wont fire

[LuisN]

Hey guys, im a bit a wits end.. Hours and days just trying to get the right side to fire.

79 xs, 120 psi both cyl
Valves checked
Chain tension checked
Points gapped

Carbs rebuilt and tested 3 sets which work on other bikes just fine

I have the pma on it, so i cant tell when its firing so cant time it. Might put old system back on just to check where tdc, f etc are.

But right side wont fire!!! Now heres the thing i saw on all the carbs we tried

If i cover some of the holes on the right side it fires a bit and tons of gas comes out.
If its at idle and i spray starter fluid it fires right up.

It has new everything on the carbs. All stock settings
Uni pos filters
Straight pipes out

Wtf!?

 

[TwoManyXS1Bs]

...Carbs rebuilt and tested 3 sets which work on other bikes just fine

But right side wont fire!!! Now heres the thing i saw on all the carbs we tried

If i cover some of the holes on the right side it fires a bit and tons of gas comes out.
If its at idle and i spray starter fluid it fires right up...

Sounds like all that's left is to check for some sort of vacuum leak on that side.
Vacuum barb?

 

[LuisN]

Its capped off, but what ill do is spray starter fluid in that area and see what happens

 

[Dyrden]

I'd say buy a ducati.

 

[TwoManyXS1Bs]

On the catastrophic side of the fence, there's the obscure possibility that the cam lobe and rocker on that side is ground down enuff to prevent sufficient intake demand, yet still seal to show adequate compression numbers. Same could happen with really thick carbon deposits on intake valve backside...

 

[NONclow]

I have the pma on it, so i cant tell when its firing so cant time it.

Do you have a strobe timing light?
Have you swapped spark plug wires left to right to see if the problem switches sides??
Carbs have been bench sync'd?

 

[Gibson]

If it runs on starter fluid, its not ignition or likely mechanical. If plug is coming out dry its carb issue. Float stuck, clogged jet etc. Try measuring float level and blow out all jets. Good luck.

 

[Gibson]

Check tank petcock(s) and lines also. If it is present on multiple carb sets you've tried, it could be clog in tank screen or lines...

 

[XSLeo]

Nobodies mentioned condensers. When it's cranking watch the points, a darkened area helps see this. Do the points on the non running side spark a lot? If so it could be the condensers.
Leo

 

[LuisN]

Itsbrand new but Yes! Its like lightning!!! Ill try it and report bAck. I recheckedcompression btw, i have 100 on left and 95-100 on right. Is that ok?

 

[Gibson]

Could be defective condenser. They are electrolytic caps and can be temperamental. They usually cause high speed problems. Resistor caps should be discarded with point system. They really neuter the spark. Measure them with ohm meter to see if that may be the problem. I've had them cause issues. Better is new wires and straight caps. It will make it run better.