[suziblu]

We were cruising along for about 2 hours at secondary highway speeds. We pulled over to check the map and the '95 Burg 400 was turned off for about 2 minutes. When it came time to continue, it turned over but wouldn't start again.

Checked the usual suspects (kill switch, kickstand etc.) and tried again. Cranked continuously (sounded a little slower than usual) for about 3-4 seconds and finally caught. Ran fine for the next 3 hours.

Other symtoms ... perhaps unrelated. Noticed cold morning starts result in Burgy idling quite rough until the throttle is increased a bit and then it smooths right out again. Burg gone about 30,000 miles, oil is always fresh.

Could a weakening battery be causing these things to happen? My experience with MC batteries is they basically just stop working vs. run down slowly.

Any insights or ideas appreciated. Thanks.

 

[Mel46]

I am not an expert but if the battery was weak it wouldn't turn over. However, what I have found on the gel batteries is that they quit unexpectedly, with little or no warning. How old is the battery?

 

[suziblu]

... snipped ... I am not an expert but if the battery was weak it wouldn't turn over. ... How old is the battery?

Thanks Mel. I'm with you in believing it wouldn't trun over if the battery was bad ... unless perhpas ... it's just starting to go and in the very early stages of its death throes.

Not sure on the battery's age because, as most of you know, it's a pain to perform a batteryectomy on a 400 and I'd have to remove and see it to be sure. Guess I'll do that tonight.

BTW - I now label all of my batteries (which ones go in what machine) including the original installed date. That helps me to keep 'em straight in my mind.

Other thoughts? ~ bugjr ~

 

[JohnK]

If you can't remember the age of the battery then it probably is time to replace it.

 

[suziblu]

If you can't remember the age of the battery then it probably is time to replace it.

Hey John, would a weak battery create the symptoms I described?

 

[JohnK]

Yes, It very well could and be a symptom of a failing cell even in a newer battery. Have you load tested the battery?

 

[suziblu]

Yes, It very well could and be a symptom of a failing cell even in a newer battery. Have you load tested the battery?

No load test yet John ... I was trying to narrow it down to a few possible issues and get a sense of direction before going gung-ho on the "physical" diagnostic bit.

This scoot is used as a daily commuter to work by SWMBO and when it is "out of service" during prime riding season, nobody's happy if you catch my drift ...

 

[Scootereno]

VAPOR LOCK!
It happens usually when a poorly vented gas cap creates a vacuum over a long higher speed ride. Happened to me twice before I started cleaning my gas cap at every oil change. Clean your cap and see if it ever happens again.
Good Luck!

 

[JohnK]

Also, check to make sure your idle is set correctly. It should be 1200-1400 when warm, if lower it could affect starting with throttle closed.

 

[suziblu]

Also, check to make sure your idle is set correctly. It should be 1200-1400 when warm, if lower it could affect starting with throttle closed.

Idle runs right at 1,350 so that seems OK.

VAPOR LOCK!
It happens usually when a poorly vented gas cap creates a vacuum over a long higher speed ride. Happened to me twice before I started cleaning my gas cap at every oil change. Clean your cap and see if it ever happens again.
Good Luck!

I think we just filled up about 1/2 hour before this happened. 1) Would opening the gas fill cap eliminate the vacuum? and 2) when you say clean your gas cap ... what exactly do you do?

Thanks, Bugjr

 

[JohnK]

Clean the seal so it seats properly.

 

[fernando]

I dont think is battery related, since when you ride at highway speed the battery gets charged, I think, although it has not happened to me, the "vapor lock that ScooterReno mentioned, could be the tipping point, since the the correlations of events you've described matches.

 

[Scootereno]

Clean the seal so it seats properly.

I soak mine in degreaser and blow it out to clean and clear out the vent holes also.

I think we just filled up about 1/2 hour before this happened. 1) Would opening the gas fill cap eliminate the vacuum? and 2) when you say clean your gas cap ... what exactly do you do?

Mine vapor locked only when I filled the gas high in the neck and always after a fillup. Never on a partially full tank. I would assume less air space enhances the situation.

You can test if the cap is venting properly by: Riding for an hour or so after filling it up and remove the gas cap quickly. If it gives out a BIG WHOOSH it is venting slow or not at all. A small pressure release is expected but not a BIG one.

Good Luck with your situation and hope you get to the bottom of it.

 

[v8eyedoc]

I dont think is battery related, since when you ride at highway speed the battery gets charged, I think, although it has not happened to me, the "vapor lock that ScooterReno mentioned, could be the tipping point, since the the correlations of events you've described matches.

WRONG..! When my gel battery was failing...at first, I thought it was because it was left out in a heavy rain storm.. BATTERY WAS 100% DEAD!

Placed it in the charger and recharged it 100% and rode for 2 more days - THEN the very same thing happened, so I placed it on the charger again for 2 hours. My Schumacher Battery Charger (which has an electronic brain) indicated that the battery was - B A D I got a new battery at the dealer for $49.00......

 

[suziblu]

... snipped ... Mine vapor locked only when I filled the gas high in the neck and always after a fillup.

Everytime we filled up that day, we did the "rocking thingy" to get as much gas into the tank as we could to lengthen our per tank mileage. I'm thinking the vapor lock condition could be the answer as it hasn't happened again since we've been back.

Thanks to all for your feedback, I'll post again if it happens again. :salute: ~ Bugjr ~

 

[JohnK]

Glad to hear, it would be a shame to miss out on the rest of the riding season up there.

 

[oakcreekeric]

i just got done chasing my tail around on an idle and start issue, it never hurts to check to see if you have spark (good strong spark)... i found i had a weak coil, it sometimes will start to give you trouble when its hot/warm..

may want to look there.. i have 30,000 on my '03 and putting a new coil in it solved the problem...

 

[dsfraser]

VAPOR LOCK!
It happens usually when a poorly vented gas cap creates a vacuum over a long higher speed ride. Happened to me twice before I started cleaning my gas cap at every oil change. Clean your cap and see if it ever happens again.
Good Luck!

Agree. If it was a weak battery, the bike wouldn't crank like that. Vapour locks are not uncommon after an engine runs hard for a while. Rocking the bike would only add to the chances that a bubble would form in the gas line.

Regards
Scott Fraser

 

[MacDoc]

I suspect vapor lock as well perhaps in combination with a weak battery.
Had a similar incident and I also was on a weak battery.

 

[moonzoomer]

VAPOR LOCK!
It happens usually when a poorly vented gas cap creates a vacuum over a long higher speed ride. Happened to me twice before I started cleaning my gas cap at every oil change. Clean your cap and see if it ever happens again.
Good Luck!

The 400 burgman does not vent through the fuel cap, the tank has an independent vent on the top centre of the tank, this has a small rubber vent hose which can and does close over causing a partial vaccum. I would also check the spark plug for colour to make sure the bike is not running weak, this could be down to blocked jets or incorrect mixture/dirty or incorrect air filter.