starting troubles

grant · Posted: January 11, 2006, 11:20 pm Post subject: starting troubles

Subject: Starting troubles
OK people, I am going crazy here. Bought a cherry looking '76 that had been sitting for years. Pulled the carbs, fixed float problems, cleaned them, had a mechanic sync them and set the valves which in his words were dead on. At this time he told me that the starters on these old bikes didn't work that well. This guy is a great mechanic and is legendary in this area for his family's history of knowledge and expertise in bikes. His father (Leroy Winters) even has a riding event named in his honor. The problem I'm having is hard starting problems. Tonight I installed new coils, new plug wires and caps, and pod filters. The battery is hot and all jetting and parts are original. The electric starter turns and cranks what I would think is fine but will not bring the motor to life at all when the temp. is cold. Not much better when the temp. is warm. I can kick the bike 'til I'm near cardiac arrest and finally get it to fire. The left side seems to miss intermittantly until it warms up and that only takes a minute maybe. Once the bike fires off and is warm the elec. starter starts it right up. It runs smooth and does not miss, cough, or do anything else while riding that poses a problem. The points are also new. Could this be a carb problem that I am oblivious to? Once it starts, it runs great and I can't imagine it having any problems. She idles fine and does not bog or lay down at all when you twist the throttle. Any suggestions would be greatly appreciated. The bike is a '76 xs 650c and looks brand new. I have owned (2) 650's before this one and never had this much trouble trying to start either one. HEP ME, somebody. Thanks, Grant

_________________
"I'm a juvenile product of the working class, whose best friend floats in the bottom of a glass". -Sat. Night's Alright for Fightin'

grizld1 · Posted: January 12, 2006, 10:20 am Post subject: Re: starting troubles

Most starting problems in these scoots are caused by electrical issues. I'd start by cleaning up all contacts in the ignition system, including the ground contacts on the condenser pack and battery negative cable. Check for good conductivity through the ignition and kill switches, and clean 'em up if you need to. Confirm timing with a strobe, making sure the advancer return springs are letting the points cam rod return to the retarded position at idle.

Pod filters are going to create some jetting issues for you.

grant · Posted: January 13, 2006, 6:32 pm Post subject: Re: starting troubles

Thanks Griz,
I've read that I'll probably have to rejet the carbs. I've been to the link on Mike's XS tips but I sure would like to have a better idea where to start before I tear 'em down half a dozen times. Wish I were more intimate with the mechanical workings on these things. It appears I'm going to get my wish. Thanks again, Grant

kingwj · Posted: January 13, 2006, 9:32 pm Post subject: Re: starting troubles

I bought my XS and pulled the carbs off and cleaned them, not much change. When I changed out the points, condensor and plugs it started much easier. I also think the vacuum petcocks may contribute as vacuum generated by the engine turning over is necessary to start the flow, just a theory. You might want to move the petcocks to the full flow position and see if that helps. Now in the wintertime with the battery at less than full charge the bike starts easily with the kick start and the electric starter won't start the bike cold. A bit of heat and the electric works fine. I'm surprised there isn't an aftermarket high cranking starter available.

Bill

grant · Posted: January 15, 2006, 10:45 am Post subject: Re: starting troubles

Thanks Bill,
I am leaning more towards a fuel problem remedy than electrical one. I have rebuilt the petcocks and I'm sure there is plenty of fuel getting to the carbs. I changed out the air filters from the originals which were crumbling to pieces from rot so there is probably a problem with trash in the carbs. My son who was a mechanic in Iraq held a couple of shop rags over the ends of the exaust and the motor immediatly starts to fire. Any theories about this?

grizld1 · Posted: January 15, 2006, 11:50 am Post subject: Re: starting troubles

A few suggestions, Grant. Since your bike runs well in the low-throttle range once it's fired, I don't think you need larger pilot jets. If you did, she'd misbehave due to fuel starvation in low-throttle running. You may need slightly larger mains, but that's not going to have anything to do with starting issues.

A lot of things in your system are temperature-sensitive and could bind cold and free up warm. Next time the scoot refuses to start, check and see if the ignition's in the full-retard position. If it is, turn off the fuel, remove the float bowl plugs, turn the fuel on again, and see if you have sustained flow on both sides. If you don't, have another look at the float assemblies.

No vacuum petcocks prior to the E-model, Bill.

grant · Posted: January 17, 2006, 6:40 pm Post subject: Re: starting troubles

Thanks for the help guys. I'm going to try some of your suggestions and go from there. I'll keep you posted as to my rate of success and what works. Thanks again, Grant

grizld1 · Posted: January 19, 2006, 9:44 am Post subject: Re: starting troubles

Hey Grant, I missed your post about exhaust restriction causing the bike to fire. You might want to check compression and recheck valve settings. You definitely want to warm the engine and reset the fuel screws and you want to do that by the book. Also, check enricher valve ("choke") operation, making sure the little forks on the rod are actually lifting the plungers.

79xs650 · Posted: April 24, 2006, 10:15 pm Post subject: Re: starting troubles

wasnt sure if you had much luck...but i sorta had the same starting problem...i had the standard battery that yamaha recomends, but i found that there is a more stronger battery for this xs 650, cb14l-a2 is the number...now my bike turns over first time hot or cold, choked or not choked...

Nick

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