750 Seca Weak Charging System Leading to Poor Cold Starts

So this winter my 82 750 Seca has been having cold start trouble. When the weather gets down real low the starter will crank and the engine will pop and sputter but won't turn over and run. Sometimes it will catch with a little bit of throttle or starting fluid but other times it takes forever or doesn't happen at all.

Yesterday the bike wouldn't start after sitting for a week since its previous run. I put it on a trickle charger overnight, and this morning (almost 20 degrees colder than yesterday morning) she fired up great with no trouble.

I've always believed this to be a carb issue and was just about to order the tools to go and hit the enrichment circuit and starter jet but now I'm thinking its my charging system being out of whack so the battery runs flat as I'm out riding and then won't have enough kick to start the engine in the morning the next day. Does this sound like the cause of my cold start issue or could it still be a carb related problem?

Also if anyone knows, why would cold weather exacerbate a weak battery issue whereas in the summer there were no issues? I'll be looking at some alternator overhaul threads in the meantime.

Edit: I'll also mention that I've gapped the plugs and put all the valves in spec recently as well.

 

Batteries don't like cold. Even a good battery produces less current when cold. The engine is also harder to crank when cold. Oil is thicker when cold, even with multi-weight polymers. It may be a problem in the charging circuit, or it may just be a weakening battery first showing issues when it's cold.

 

^^ what he said, and...

How cold is your cold?

What condition are the starter motor brushes in?
What condition is the electrical system in?
Have you measured the voltage drop between the battery and the starter motor?

 

Below 40 the issues start but this weekend was hovering at 30 and under.

I am going to check the brushes this week. As far the electric goes, I gave all the lines a pretty good look earlier when I had to redo some wiring and most of its in pretty good condition from what I can tell. Fuses are all up to date and what not. Anything else I should check?

I checked voltagea on the battery and starter when the weather was warmer but I think a recheck is necessary.

 

For comparison purposes my Seca 750 is an easy-starter down to 30ºF.

 

This time of year, I'm sure I'd have less starting issues with mine if I kept her in the living room... Maybe I'll lobby for that next week... It is Valentine's Day Eve you know...

 

I've heard a lot of comments about how these bikes don't like the cold but I have a feeling its just the age showing. If everything else is running right I'd imagine they start just fine like k-moe said.

 

cold is not a real issue if everything is right. your oil must be correct for the temp too.

charge your battery hook meter to it and see how much the voltage drops when you hit the starter button . if it drops below 9.5 volts before it starts you will have issues with starting because the tci does not like low voltage
then when bike starts check the voltage throttle up to 2k rpm and see where your voltage goes it should go up to 14+ volts
from
The Information Overload Hour which i suggest you read it will give you more details
For all XJ-series models, the maximum available charging output VOLTAGE should be as follows (all values are approximate):

* approximately 500-2000 rpms: 1.8 volts gradually increasing to 14.2 volts
* 2000+ rpms: 14.2 volts up to about 14.8 volts, with a maximum of 14.8 volts (all models except XJ700-X and XJ750-X)
* 3000+ rpms: 14.2 volts up to about 14.8 volts, with a maximum of 14.8 volts (all XJ700-X and XJ750-X)
end quote
if not you may have a charging issue or could be dirty connections. clean at battery and soleniod for + and at battery and where the wire connects to motor and frame for-

 

Yep, but you do have to let them warm up for a minute or two before riding off.

 

Like I do in most cases, I blame the carburetors. Carbs just don't have much range in adjusting enrichment for cold conditions. Cold fuel doesn't vaporize as easily, and sticks much more easily to the walls of the cold intake port. My Seca starts just fine at temps as low as 0F, but this is not the case for the Virago next to it (which is still carbureted). IMO, if a carbureted bike starts easily when it's that cold, it's probably going to be way too rich at normal temperatures.

 

My Seca, my garden tractor (snow duty in the winter), '83 GMC pickup (sold a few years ago after 2o years of ownership), '75 Celica (first car I bought), '74 260Z (Dad's car), and the hand-me-down '81 Chevette (family car and then teenager car); all started well in the cold (below 30ºF), and none were overly rich in the warm (though the truck required a few squirts from the acclelerator pump).

 

No accelerator pumps in these carbs, and nothing like the enrichment circuit you get in a four barrel. Have you really checked the running mixture of your tractor? Our snow blower starts well enough, too, but that's with a real choke, and having pressed a prime bulb five times or so to force a bunch of fuel into it.

0F is also quite a bit colder than 30F, and easily vs. well is pretty relative. Pushing the starter button once, for a few seconds or less is what I consider "easily."

On the other, other hand, I don't usually ride when it's that cold, but I do sometimes work on the bike under such conditions in the garage. I have friend who does ride under all sorts of cold weather conditions, even below 0F. He has an FI Kawasaki 600, and a KLR 250 and DR 400 that are carbureted. For the really cold days, it's the 600 that gets ridden.

 

No accelerator pump on the Z car (Zenith-Stromberg constant velocity carbs built under license by Hitachi). Quadrajet had an electric choke. The garden tractor does not run rich. I stand by what I said, because for me it's 100% accurate. YMMV yada, yada, yada. FI is better (except when it isn't, just like every other thing there ever was). Not for children under 3 years old. And yes, I agree, It's ALL relative

 

It's not that: the bikes don't like the cold, as much as it is that: the BATTERY doesn't like the cold.

My sleds will start on usually three pulls even at near zero. My car fires right up at -15.

My bikes will fire right up if the battery is on a tender or charger, but if its cold ( like under 30) and not FULLY charged, she ain't gonna start. But I know once I top it off and the temp warm up she'll fire right up.

 

Batteries certainly don't like cold, but I also have the before and after experiences of converting two of my bikes to fuel injection. And FI puts more of a load on the battery.

I will throw one other factor in there: in the winter, the bikes don't get ridden as often, and fuel injection is also MUCH better at picking up right where it left off, even if it's been sitting for a couple of months.

 

+1 on that.