Bike won't start when it's cold - too rich?

[Guest]

Did you set or check the carb float heights to spec after the carb work? I am having some similar issues, and the floats are a tad too high, (my carbs are off a '94 Suzuki). Bike started without choke, or with very little choke in warm weather, and runs great, but cold weather starts are no fun.
Tony.

 

[sultan]

try boosting it with a good car battery as a test, you may have a poor battery consequently low cranking speed and low voltage to the coil while cranking

It's an almost brand new battery, and even after a full charge on a charger, it does the same thing. However, I had the same idea, and the bike still won't start, even while hooked up to a car battery.

 

[sultan]

Did you set or check the carb float heights to spec after the carb work? I am having some similar issues, and the floats are a tad too high, (my carbs are off a '94 Suzuki). Bike started without choke, or with very little choke in warm weather, and runs great, but cold weather starts are no fun.
Tony.

I did check the float height while rebuilding the carbs. Had to post to the forums to figure out where to take the measurements from, but according to the manual, everything should be in spec now.

 

[almarconi]

Assuming I had the correct hose, this did nothing.
Which one is the breather hose?

Battery voltage at battery, with key off:12V
Battery voltage while cranking: 11V

Voltage at coil (if I'm reading it at the right place)
while key is off: 11V
Voltage at coil while cranking: 10V

The hose you want is attached to the carb, there are two of them one on either side of the bike.

IMHO your battery voltage is too low. A fully charged battery should be reading about 12v, I would expect to see 12.6-12.8v. Your voltage at the coils should be the same as at the battery. More than likely you don't have enought voltage at the coils to get a good spark. I would start by doing the coil mod to ensure full voltage to the coils.

Did you check to see if your RR and stator are working properly?
It is also important to make sure your ground connectors are clean and tight. I would remove the headlight and check all the wires in the headlight bucket to make sure you don't have any burned connectors. Also look at the wires leaving the RR and make sure these are clean and tight.

 

[82Shafty]

I meant your spark plug boots

http://www.z1enterprises.com/detail.aspx?ID=425

They unscrew off of your plug wires.

 

[twistedwankel]

'83 GS650, 23K miles. All summer the thing has been running great! With the choke half-on, I'd just have to tap the starter once and it would fire right up. Compression is 175 (or better) on all 4 cylinders.

As the temperature has dropped though, it's become harder and harder to start. Today, for the second time this fall, I cranked (and paused) and cranked (and paused) until the battery went dead. (Interestingly, it did the exact same thing with the same symptoms *last* fall when the temperature dropped, which prompted all the work in the spring. In a pinch a couple of times I used starting fluid in the air filter, and doing that caused the bike to fire right up.)

Ideally, I'd like to ride the bike until the roads get bad, but I can't do that if it won't start. Any advice is appreciated.

Thank you.

I feel for you (I once thought of having an ether tube installed). I'm on my 2nd GS now and they both were/are really cold blooded below 70F. I finally left them on the battery tender anytime when I wasn't using them daily. If they sat for more than three days I would turn on "prime" before starting as some gas apparently was evaporating from the bowls (not leaking-I checked). I virtually always had/have to use full choke on the first daily start and let the thing run for 10+ minutes to get any heat into the engine and be able to turn the choke fully off.

My present original stock 81-750E starts the same as my old original stock 82-450L. Everything electrical/fuel/valves was gone over on both. One thing that did help alot was to run a direct ground from the Rectifier to the Negative battery terminal - site suggested. It raised the volts (I have a meter installed) from 12.3V to 13.8V at idle now with lights on. That is a big deal for these little batteries and original weak coils (but you changed yours-I didn't.). If you can't turn off your headlight the relay starting headlight (Steve) mod on this site is a great idea.

I still have to use full choke (first start of the day only) but it pops right off hitting on 2 cyl (sounds like it anyhow) and within a few seconds will rev normally and can back off choke to 2k. On an 80F day I can crack the throttle a 1/4 turn with no choke and hold it until the bike will rev by itself and idle (about one minute).

I was able to start the '81 with a dying battery showing only 8.2V while cranking and it actually fired when slightly warm. I have occassionally push started these bikes with a slight roll in 1st gear when the battery is weak rather than killing it entirely (no juice for coils).

For some reason once they get flooded by gas a little shot of ether into the airbox will fire it off immediately (volatility diesel issue?). You do what you have to do when you have to go in the snow!!

I suppose you could keep the bike in a heated garage or invent a block heater like in Canada?? They are cold blooded!! I now live in FL and even when 90F my bike cools so fast that within 15 minutes of sitting off the idle is dropped down upon restart and takes 10 minutes to get back up to operating temperature. So much for worrying about overheating these aircooled motors.

Once I got a slug of fines/rust into the carb bowls which I flushed out by draining the bowls repeatedly,replace rusted bolts and installed a gravity prefilter - no more rich running.

You will develop a cold starting system that works eventually. Like all cold blooded creatures they like to hibernate in winter. That's why I retired in the South and ride year round now Good luck.

 

[82Shafty]

After the relay mod and new plug boots, my bike pops and fires on the first revolution even on a 38 degree morning after it has sat for a week.

The great thing is I dialed the A/F ratio in when it was 80 degrees out and have not had to compensate for the cold weather.

 

[sultan]

I meant your spark plug boots

http://www.z1enterprises.com/detail.aspx?ID=425

They unscrew off of your plug wires.

I also replaced the spark plug boots with NGKs this past spring. ; )

 

[Guest]

here is a long shot that happened on the 1150.....one of the bolts in the linkage that lifts the enrichment rods was loose so when i put the choke on only one enrichment rod was being lifted, I think you are too lean....confirm all of the enrichment rods are being fully lifted and don't touch the throttle when starting cold.

 

[sultan]

Fixed?

Fixed?

I'm not yet sure this is fixed, but thought I'd follow up with an update.

Ran into a problem last weekend due to stripped oil filter cover studs...messy. Had to wait for parts. It's all back together now and running.

Last weekend and this past weekend I:
-changed the oil
-put the battery on a charger overnight
-reseated all 4 carb fuel needle valve/screws, and took them out 2 turns

I rode the bike on Sunday, and it was about 45 degrees. The bike sat for about 6 hours and started right away (second try) and I was able to make it home. I've been going out to start the bike the past few mornings just to see if it will continue to start, and there's been noticeable improvement. Yesterday morning (~40 F) the bike started with 2 tries. Last night (12 hrs later, ~40F) it started on the first try. This morning (a brisk 35F) it also started right up on the first try.

Also, after doing these things the lagging/bogging at lower RPMs seems to have fixed itself. I'm getting good pickup at lower RPMs in addition to above 6K.

Honestly, I think it was the fuel screws. I *know* I set them to 2 turns out when I cleaned and rebuilt the carbs. And, it's not like they're loose enough to turn on their own with engine vibration.

I know some will say that it's the battery charge that fixed it, but if that's the case, why wouldn't it start previously when I hooked a car battery up to it? And, changing the oil shouldn't make any difference, right? Maybe it's slightly easier to turn, but not enough to effect starting the bike.

So, that's where I am. I'm hoping for a good, cold, 10 degree day soon so that I can be sure that this is actually fixed. Thought I'd give an update to see if anyone has any feedback and in case this might help someone else in the future.

Thanks!

 

[Overdrive]

I don't have any feedback (new to all of this), but I'm glad I decided to take a look at this thread. I'll probably have to come back to it soon, because I've been encountering a similar problem as the temperature drops around here. I had to crank my 650 about six times today at full choke (with plenty of sputters and almost-there moments) to get it to finally fire up and run for a few minutes.

 

[trippivot]

dont see what the hell this would do but err okay.

blowing into the vent tube floods fuel into the engine thru the carbs .

battery voltage is very important in the cold.
keep a can of quick start . be smarter than the bike, ether is a good tool
cold no start could be a tight valve or weak spark,low dynamic voltage and a wearing starter..

 

[sultan]

blowing into the vent tube floods fuel into the engine thru the carbs .

battery voltage is very important in the cold.
keep a can of quick start . be smarter than the bike, ether is a good tool
cold no start could be a tight valve or weak spark,low dynamic voltage and a wearing starter..

I think I did finally try the vent tube thing correctly. You have to do this *while* starting the bike, or just just before trying to start the bike? Either way, the bike went from sputtering and trying to start to just cranking and *not* sputtering and trying to start, and bogged down (the starter turned the motor over slower). I'm still thinking that I was running too rich, and pushing more gas into the cylinders just exacerbates the problem.

The battery is holding voltage as far as I can tell. If it's not starting I can get a good 20 or 30 tries as getting it started, at 10-15 seconds each. Also, even if I kill the battery to the point where it won't turn the motor over, if I let it sit for a minute, it will get enough charge to roll it a few more times. I'm thinking if the battery were dead that the motor would turn slower and I wouldn't get this much 'juice' out of it. Also, the starter does crank the engine at a good clip (as fast as I would expect...about as fast as it does during the summer) so I'm thinking/hoping I'm good there.

Did a valve adjustment less than 100 miles ago. All but 2 were completely in spec., and the 2 that were out were so close that swapping to the next smaller shim put them out of spec the other direction.

Thanks for the reminder about the starter fluid! I have a can of it from last fall when the bike left me stranded, and I've been meaning to attach it somewhere to the bike in the even that the same thing happens again.

Took 3 tries and some sputtering to get the bike started this morning, but it did finally take off. (35F) So far, so good, I think.

 

[almarconi]

I think I did finally try the vent tube thing correctly. You have to do this *while* starting the bike, or just just before trying to start the bike?

A couple of puffs into the breather tube, full choke and hit the starter. Do NOT touch the throttle. It should start.

 

[pbdavey]

I have a GS550 that I don't use the starter when it's cold...I end up kicking it over...a lot (not that some people have that option). But I was thinking about this issue and came across this possible solution. I might make a thread about this to get feedback specifically on what people think of this.

http://www.reiffpreheat.com/Motorcycle.htm

 

[tomo]

The vent tube trick is best done before trying to start the bike. Like Almarconi says, a couple of puffs into each tube, pull up the choke, then try the starter but without using any throttle.

 

[Guest]

I have a GS550 that I don't use the starter when it's cold...I end up kicking it over...a lot (not that some people have that option). But I was thinking about this issue and came across this possible solution. I might make a thread about this to get feedback specifically on what people think of this.

http://www.reiffpreheat.com/Motorcycle.htm

The heater when used on the oil-pan, will benefit those who ride in cooler temps (around freezing) by providing better flow after start-up, and perhaps make it easier on the starter. However, if starting problems are carb related (poor atomization of fuel when cold), it probably won't help.....an electric space heater blowing on your engine for a while before attempting to start might be better:-k (I have been meaning to try this myself, but as yet have not).

Tony.