Another right side backfire

[MickFerreira]

I bought this 1983 XS650 and wasn't running right, the kid messed with jetting so I bought a TC Bros Mikuni setup pre-jetted. I am at sea level. I immediately got a right side exhaust backfire which at times ran back through the carburetor. I depressed the choke and it went away but the tight side plug fouled as it was running so rich. I went a step further and got the billet intake and new rubbers / clamps and it didn't change, still have backfire. I have an exhaust leak on the left side which I will fix.

I cant figure out why the pap-pap-pap pow ! sound even though I have new carbs and intake. I don't have points or timing on the 1983 model. Help ! I don't have enough experience with these bikes as I do with my Harleys.

 

[gggGary]

Let's see some more pics!
'specially the zaust 'n air filters.

 

[grizld1]

Never, ever assume that installing a new carburetor is a bolt-on job. Strip, flush, list jets, and inspect fuel level--and if you have to adjust fuel level, do not, repeat not, move the tang on the float lever in a VM34--adjust the arms on the lever. A quick search will turn up the details for you, not gonna write it all out again. That having been said, ham-handed owners have been known to crank down hard enough on carb mount screws to extrude the edges of the holes in the cylinder head. If that happens a new mount with fresh gasket plus the toughest gumpucky you can lay hands on will not, repeat not, solve the problem; careful dressing with a fine flat file will (inspect the file before use; many flat files aren't). Be sure to eliminate compression, valve lash, and ignition problems. Sure, you have TCI, but a bad plug, cap, or wire can cause grief too.

Edit--wrote BS34, meant VM. Corrected.

 

[jussumguy]

How about checking the valve lash adjustment. If the bike was run hard and not maintained the intake valves may be tight. Borrow the right tools and spend a little time reading or watch a YouTube video and adjust em!

 

[MickFerreira]

That was one of my first thoughts. Perhaps the valves are loose and allowing fuel past them during compression and detonation is happening in the exhaust. I used to adjust valves on Volkswagens and Porsches so it is pretty straight forward and easier that a car.

 

[gggGary]

Be sure to eliminate compression, valve lash, and ignition problems. Sure, you have TCI, but a bad plug, cap, or wire can cause grief too.

Set the cam chain tension while you are at it.

 

[MickFerreira]

Let's see some more pics!
'specially the zaust 'n air filters.

 

[MickFerreira]

Set the cam chain tension while you are at it.

Where is the quickest place I could find how to adjust valves? I made sure I have no exhaust leaks now and it won't kick over. I am using starter fluid too.

 

[gggGary]

This should do it
http://www.xs650.com/threads/valve-adjustment-video.13083/
I like .006" exhaust .003" intake

 

[MickFerreira]

Thank you kindly gggGary.

 

[MickFerreira]

So now I left a light on and killed the battery. I got a new battery and now it doesn't even start. I am going to take it to a shop that specializes in old Japanese kick Start only bikes. Took my 2012 Kawasaki Ninja ZX6R 600 to get the fuel system cleaned out after it had been stored 4 years with a tank of bad gas. Has only 1,138 miles and paid only $1,500 for it.

 

[member28833]

So now I left a light on and killed the battery. I got a new battery and now it doesn't even start.

"Spark" ?

 

[MickFerreira]

I am not sure what may have occurred since the battery died and it was running before but with a new battery now it does not. I zip tied the connections together when I removed them from the battery to ensure replacing them correctly. I cleaned the plugs.

 

[gggGary]

Leaving a light on also means the ignition was left on?

 

[gggGary]

The TCI has a built in "anti self destruct mechanism" shutting itself down when it does not receive a signal from the pickups after a set period of time. which should also protect the coil from burning itself out. But I'd be checking all my ignition components using the factory service manual.