Starting Saga

[Gpaws1968]

Hi all,

So my starting saga continues on my 1981 XS650, if I start it with the starter it turns and turns over fires up and battles to stay running and if it stalls it's best to just let it sit for 5 minutes, but if I kickstart it fires up. The battery is fine at 12 volts.

 

[olewahrhorse]

Hi all,

So my starting saga continues on my 1981 XS650, if I start it with the starter it turns and turns over fires up and battles to stay running and if it stalls it's best to just let it sit for 5 minutes, but if I kickstart it fires up. The battery is fine at 12 volts.

I've been having similar problem. Hard starting with occasional backfire thru the carbs. Ran real rough while warming up. One of my issues was weak springs on the timing advance weights. The weights weren't completely close so the engine had some advance when trying to start. My other problem was cam chain stretch. I got my advance unit working correctly and adjusted my cam chain. Then reset my timing. It is starting a lot smoother.

When you say "best to let it sit." Will the starter turn the engine over, but the engine won't fire? Or doesn't the starter turn over? Is it possible the starter is hanging up? You need to clarify that statement a bit. It is possible to have 12v at the battery, but not down to the starter. Possible corrosion on the wiring at the starter or the start solenoid.

My humble opinion is you either have a starter issue or a timing issue. good luck!

 

[Vincenthdfan]

The starter is taking away voltage that your ignition system needs to ignite. If you have borderline voltage available this will happen consistently.

 

[jetmechmarty]

Having this issue myself. Dismantling the starter and cleaning it up is probably in order. Brushes won’t hurt either. Actually doing it is going to be my issue. I have at least two starters to run through.
My recently resurrected SH fires on the electric leg without issue. Just the same, I cold start with the kicker. It usually takes just one.

 

[DogBunny]

Hi all,
The battery is fine at 12 volts.

12 volts is weak. Google:
"what should a motorcycle battery voltage be"

 

[Gpaws1968]

I've been having similar problem. Hard starting with occasional backfire thru the carbs. Ran real rough while warming up. One of my issues was weak springs on the timing advance weights. The weights weren't completely close so the engine had some advance when trying to start. My other problem was cam chain stretch. I got my advance unit working correctly and adjusted my cam chain. Then reset my timing. It is starting a lot smoother.

When you say "best to let it sit." Will the starter turn the engine over, but the engine won't fire? Or doesn't the starter turn over? Is it possible the starter is hanging up? You need to clarify that statement a bit. It is possible to have 12v at the battery, but not down to the starter. Possible corrosion on the wiring at the starter or the start solenoid.

My humble opinion is you either have a starter issue or a timing issue. good luck!

The starter is fine, if it fires up but then stalls I let it sit for 5 minutes or so, but yesterday I had better success by not giving it any throttle and just letting it idle for a couple of seconds then giving it some RPM.

 

[motormike]

Pull headlight fuse.. ? try it..... perhaps that might help direct the needed corrections ?..

 

[JJames]

12 volts is weak. Google:
"what should a motorcycle battery voltage be"

+1 on that . A healthy, fully charged battery is a must before trying to diagnose any other issues.

 

[gggGary]

#1!!! Get a volt meter on it, watch what goes on. I suspect any or all of these;
a barely or not working charging system.
bad, dirty grounds, The ground strap from battery to frame often rotted, dirty end connections.
bad fuse holders, notorious (XS650 Special) issue
any/many other bad wire connections, dirty switches.
cracked worn pick up coil wire under cover by sprocket
fouling a plug. Heat clean dry, retry.
crappy plug caps wire connection to the plug cap.
Best course is methodical maintenance checking all of the above.
There are multiple threads on fixing every issue listed.
Feel free to;
Take lots of pics
Tell us what you have and HAVEN'T done so far.
Ask for more help.

 

[toglhot]

The 12 volt system is a misnomer, it is actually a 12.8 volt system. Whilst the difference between 12 volt and 12.8 volt seems bugger all, it is a great deal. 11.8 volt and below is considered flat, at 12 volts it is only around 20 percent charged. at 12.3 its roughly 50 percent charged.

The stock alternator puts out very little at idle. Continual starting and idling will see your battery flat.

BTW, that 12.8 volts is after it has been at rest for about an hour. Coming straight off the charger it will be more like 13.8 with a stock alternator, and up to 14.4 off a PMA system. 14.4 volts is considered the limit, anything over and your battery will be consigned to the bin.

Spitting back through the carbs can also be caused by valves not seating properly.