Bike wont start and idle.

[Tonka]

Im reading through all of the informational troublshooting threads as well as starting to go through all of the possible mantinience in my manual. Just wondering if anyone has had similiar issues and can steer me in a direction or narrow down my plan of attack. The motor is a 71, I believe its been rebuilt before but no idea if it was done right. The bike would not run when I got it, it would kick over but wouldent idle. I changed the points and condenser and no change. It has straight pipes and was way lean so I added some baffles to the pipes to give it some back presure and even out the jetting. I took it to a mechanic that rebuilt the carbs and jetted it correctly but kept having timing issues where it would be timed correctly, start and run fine and then as it ran the running condition would deteriorate and the the timing would be off. I got the bike back with plans to solve the problem myself. I put a pamco and pma in hoping that it was just an issue with the points but no luck. After the pamco install the bike started right up as It did for the mechanic and it ran fine for all of 10 minutes untill the running condition began to go south, I took it out for a ride and it was good at first through low and high rpm. It then started by stalling on idle and then began backfiring when revved, it was as if the jetting and timing was off as the engine warmed up, that was a week ago. So as of now, the bike has a fresh battery (wich has been tested), a fresh ignition, alternator carb rebuild and fresh fuel. The timing was close when it was running. Now I cant even get it to fire up. It occasionally will fire and turn right back off, any attempt to give it throttle and it imediatly turns off. The wiring has all been checked and since its in an amen savior frame with no turn sigs or horn there isnt much wiring to go wrong. Its getting fuel. Im going to start with checking the cam chain. I beleive that the issue is somthing internal that is either loose or just not reacting to the warmed up engine as it should. Please throw any and all ideas out at me. I dont mind tearing into this thing but Im learning as I go. Ive done carb work and general matinience but have never torn down a bike engine before.

 

[retiredgentleman]

You should take a careful look at the ATU. That is the advancer shaft and the fly-weights located on the right end of the camshaft. The advancer shaft must be free to rotate and the fly-weights must snap back from the open position.

If it has not been serviced in many years, it likely needs to be taken apart and lubricated.

 

[Kathos]

Try turning up the idle screws a little bit before you try anything else

 

[Tonka]

I forgot to add that I got the e-advancer with the pamco so ive got no advancer mechanism anymore. I tested to make sure I was getting 12v on the power through the e-advancer and also that Im getting a voltage spike on the green wire when the engine cranks and I am. Although Im not sure what the voltage should go to on green when cranking? Seems to be around 2v but thats without starting. I did remove the spacer to make sure that the advancer and cam pins were both secure in the slot in the spacer and they were. Ive messed with the idle screws and nothing, its seems like the more fuel I try to give it the less it wants to fire. I feel like its timing/spark related but not a pamco issue. Could the cam chain being f'd up throw things out of wack? I found a thread on here covering alot of the matinence I should have done when I got the bike so Im going to start there.

Also, the bike behaved like this for the mechanic before the pamco/e-advancer and pma install so I think there is a good chance that the issue is not related to those systems because he had gone through the points and atu and had the same issue with running almost perfect for about 10 minutes and then it just falling off and going to shit.

 

[TwoManyXS1Bs]

Might find some help in here:

http://www.xs650.com/forum/showthread.php?t=26803

 

[Kathos]

Just a hint because I made this mistake. Power going into the e-advancer should be on the "coil" side. If you have power on the sensor side, you will not be able to start your bike.

The power going into the coil should be 12v. The green wire is grounded when the coil is sitting and the green wire circuit opens, it tells the coil to fire.
Watch this video

 

[Tonka]

I know that the pamco and e-advancer are wired right because I had the bike working after the install. I had initially had issues with the pamco install because the advancer pin dident seat in the spacer and turned a slight bit wich prevented it from firing. Once I found that and filed the spacer so the pin would seat it fired right up. I checked again last night to make sure the pin hadent moved again but it was snug it its home.

 

[Tonka]

Might find some help in here:

http://www.xs650.com/forum/showthread.php?t=26803

Thanks for the advise. Found some good stuff on there and also started going through all of the maintince vids like I should have before.

I got it going again. Had a clogged/ crimped gas line. Was getting enough fuel to occasionally start and sputter out but not enough to run. Timing is right on and the Pamco and PMA are working properly. I also checked my cam chain tensioner and valve clearances. The issue Im running into now is that it will idle and run well but after being on for 5-10 minutes it will pop and stall at idle. It starts right back up, ive messed with the idle screw and no change in setting seems to change this behavior. I havent taken it out for a ride but Ive let it idle in the garage for about 20 minutes and once it warms up it seems to do this every 2 minutes or so. Any idea's?

 

[Brian902]

Might still be a fuel starvation issue.

Remove the carb drain plugs and with a pan to catch the fuel open the fuel taps and watch for good flow.

 

[gggGary]

Gas tank vented? crack the cap open see if anything changes.

 

[gggGary]

Oil on the plugs?
The early cams were not designed for smooth idle. Few motorcycle engines like to sit and idle for 20 minutes. Not hard to imagine that "vapor lock" (hot carbs, fuel boiling) could kick in.

Can't stop myself; The old KZ1300, after it had been running for awhile in hot weather if you opened the gas cap you could watch the fuel boiling in the tank! SCARY!

 

[pamcopete]

Tonka,

Do you have a giant fan in front of the engine when you run it in the garage for 20 minutes? The engine is air cooled and running it that long without any air flow will overheat the engine which could result in the rough running you are experiencing. You could also cause some serious damage to the engine as well.

 

[Tonka]

Im having a new issue. Im guessing its a carb issue and I need to review the carb guide but ill still ask in case its not and someone has had the same issue. The bike is now kicking right over and idling great. In nuetral I can throttle it all the way through the rpm range with no sputtering or backfiring. Ive taken the bike out a few times now and it reacts differently with load on the motor. When Im starting off in 1st it seems to want to bog and I need to give it ALOT of throttle to start off. Then when cruising Im getting some backfiring. Carbs right? But why do they react differently when moving vs stopped? Ive messed with the idle screws and nothing seems to effect this. I dont have a tach so im not exactly sure what rpm im getting some popping at.