Slow Cranking After Warm Up

[Hoomgar]

My older Chevy engines would do this because you would advance the timing when tunning them to larger 4-bees. So when warmed up you knew to expect that when you shut her down at the Turkey Hill to get an iced tea she was going to crank like it had a dead battery when you fired it back up.

My 550 does this too. It will crank fine when cold or even after warmed up as long as it isn't more than a 5 to 10 minute warm up. But after a good 20 minute ride or longer it does this same hard cranking thing where it seems like the battery is dead. It isn't a dead battery as you can put a meter on it and it tests fine. I also just put a new battery in it yesterday and was hoping that this problem would go away. But it still does it. If you were to let it sit until it cooled down then it will crank normal again. Is this the same as with the Chevy engine? The timing is too advanced?

It also still starts hard when cold. If it has been sitting for a day I cannot start it without spray. I cleaned the carbs last month and this got a lot better and I was even able to get it to start while cold on a few occasions. Now it is back to no starts when cold. I checked the voltage when the engine is running and with it at about 3g or so I am getting over 13 volts so the stator seems to be doing it's job. Could this problem be related to the problem listed above and be timing also?

Any ideas?

 

[Anonymous]

it sounds like you need to replace the starter itself, if the windings get too hot it requires more amps to turn over.

 

[Hoomgar]

I'll check that. Thanks.

 

[earlfor]

Re: Slow Cranking After Warm Up

Mark, my inclination is that the starter is pulling the voltage down too much and consequently the ignition is too weak for the bike to start. As already said, your starter probably needs a little refurbishing. I recently completed a rebuild/refurbish on a 78 GS 1000 and it starts in about 3 seconds with 1/3 choke, no matter how long it has been sitting. The carb settings I settled on were, fuel pilot screws 1 1/4 turn out, airscrew 2 turns out, timing on the normal marks (no additional advance). This with stock pipes and airbox. Carb synch set to 10 in.hg @1200

Earl

It also still starts hard when cold. If it has been sitting for a day I cannot start it without spray. I cleaned the carbs last month and this got a lot better and I was even able to get it to start while cold on a few occasions. Now it is back to no starts when cold. I checked the voltage when the engine is running and with it at about 3g or so I am getting over 13 volts so the stator seems to be doing it's job. Could this problem be related to the problem listed above and be timing also?

Any ideas?

 

[Hoomgar]

Alright thx Earl. Looks like I will check the starter next then. I guess the easiest way is to just replace it. I know where one is that I can get cheep that is known good out of a 750. The guy tells me it will fit. What do you think?

I did find something just about an hour ago in the dark. I have been hearing this clicking sound that I thought was a timing chain noise. Turns out I am arching from the #3 spark plug boot to the head. In the dark you could see it plainly. I know this can't be good either. I am going out in a bit to see what if anything I can do for that.

 

[Anonymous]

The commutator bar might just be dirty. Take a look inside first.

Steve

 

[Hoomgar]

The commutator bar might just be dirty. Take a look inside first.

Steve

What is this communtator bar you speak of Steve?

 

[Anonymous]

It's the part the brushes ride on. It will get black with carbon and turn slowly.

Steve

ps. I posted a seca turbo for sale in the GS Stories section :twisted:

 

[Hoomgar]

So I need to pull the starter and open it then?

hmmm


Turbo you say eh?

 

[earlfor]

I had some starter work to do on the 1000 also. It appears the 750 and 1000 use the same starter. If it really is out of a 750, it should bolt right in perfectly.

Spark plug boot may be cracked. As a temp fix, wrapping it with electrical tape will probably keep it from arcing.

Earl

Alright thx Earl. Looks like I will check the starter next then. I guess the easiest way is to just replace it. I know where one is that I can get cheep that is known good out of a 750. The guy tells me it will fit. What do you think?

I did find something just about an hour ago in the dark. I have been hearing this clicking sound that I thought was a timing chain noise. Turns out I am arching from the #3 spark plug boot to the head. In the dark you could see it plainly. I know this can't be good either. I am going out in a bit to see what if anything I can do for that.

 

[Hoomgar]

I had some starter work to do on the 1000 also. It appears the 750 and 1000 use the same starter. If it really is out of a 750, it should bolt right in perfectly.

Spark plug boot may be cracked. As a temp fix, wrapping it with electrical tape will probably keep it from arcing.

Earl

Alright thx Earl. Looks like I will check the starter next then. I guess the easiest way is to just replace it. I know where one is that I can get cheep that is known good out of a 750. The guy tells me it will fit. What do you think?

I did find something just about an hour ago in the dark. I have been hearing this clicking sound that I thought was a timing chain noise. Turns out I am arching from the #3 spark plug boot to the head. In the dark you could see it plainly. I know this can't be good either. I am going out in a bit to see what if anything I can do for that.

Were talking KZ750 LTD starter for my 550 Earl. I knew that a lot of 750 and 1000 parts could be interchanged as you say but the 750 and 550? Seemed odd to me that's why I asked.

The boot I could not see a crack in. But I did what you had said I used to be an industrial electrician so I still have some rolls of hi-temp fiberglass electrical tape. I taped her up good and it will be a perm fix now

I am going to pull the starter I guess next to rip that apart.

 

[earlfor]

Oops Mark, I thought we were talking GS 750 starter into a GS1000.
Well, as one gets older, the eyes start to go and reading retention skills decrease y'know.

Earl

Were talking KZ750 LTD starter for my 550 Earl. I knew that a lot of 750 and 1000 parts could be interchanged as you say but the 750 and 550? Seemed odd to me that's why I asked.

 

[Hoomgar]

Oops Mark, I thought we were talking GS 750 starter into a GS1000.
Well, as one gets older, the eyes start to go and reading retention skills decrease y'know.

Earl

Were talking KZ750 LTD starter for my 550 Earl. I knew that a lot of 750 and 1000 parts could be interchanged as you say but the 750 and 550? Seemed odd to me that's why I asked.

LOL! Tell me about it

 

[KEITH KRAUSE]

As stated earlier, clean up the commutator and check the brush length. You could also have a wiring harness connector(s) going bad and building up heat that's only noticable at hot starts. Could also be the R/R causing the battery to over-heat.
If it's carb related and the problem gets worse as the motor gets hotter, then it's usually a richness problem. But this contradicts the fact you need to spray the carbs to get started after a day of sitting. I know you say the carbs are clean. Have you tried adjusting the mixture screws to allow a leaner setting? This may help the hard starts when the motor is hot. Needing spray at cold start up usually means the pilots are not drawing fuel well or a poor carb sinc'. You did say it's getting steadily worse. There may be rust particles, etc, clogging the pilots?

 

[Hoomgar]

As stated earlier, clean up the commutator and check the brush length. You could also have a wiring harness connector(s) going bad and building up heat that's only noticable at hot starts. Could also be the R/R causing the battery to over-heat.
If it's carb related and the problem gets worse as the motor gets hotter, then it's usually a richness problem. But this contradicts the fact you need to spray the carbs to get started after a day of sitting. I know you say the carbs are clean. Have you tried adjusting the mixture screws to allow a leaner setting? This may help the hard starts when the motor is hot. Needing spray at cold start up usually means the pilots are not drawing fuel well or a poor carb sinc'. You did say it's getting steadily worse. There may be rust particles, etc, clogging the pilots?

Well I just completely disasembled and cleaned the carbs last month as you know and cleaned out the fuel tank and checked the fuel screen. Everything looked fine as far as not showing any signs of rust or particles of any kind so I don't believe that would be it but you never know. I also don't want to lean it out because it is already running just a little on the lean side so I know that isn't it. It could be carb sync as I don't really know what I am doing there. I think I am going to check the starter next because several of you have said that and even Paparo suggested it could be that.

But for right now, we ride!

I'm off for some fun in the sun, bbl ppl

 

[KEITH KRAUSE]

Whaddaya mean "we ride"? :x I gotta mow the %#!*$@! lawn! If this light rain would stop.

 

[Hoomgar]

Well I am back. And that was a good thing the bike needed. A good run to see what is up with it. I put 227 miles on it only stopping for fuel and to use a bathroom at the same time. The bike ran almost flawlessly the whole time although after about 100 miles I am hearing a rattling sound in the top somewhere. Not sure if it is valve rattle, cam chain rattle or just something else loose on the bike somewhere. I couldn't narrow it down. But it didn't seem to affect the performance any. It is right between 3 to 5 grand.

But as stated earlier once warmed up on a long run like this it would not crank at all. I had to push start it so that fuel/bathroom stop was my one and only stop for the entire ride.

I am going to have some diner and let it cool down and then go out again for some more.

Sorry Keith, it is gorgeous here today brother

 

[argonsagas]

By all means check the commutators.....it is easy to clean them up, just use a bit of 160 emery paper.

If it is continuing to worsen, look for a bad ground wire/cable. I had one of these years ago....it would start OK when cold, but cable was dirty. It would flow ful voltage, but could not deliver the amperage draw once warm, as the connector had swelled a bit, and lost full contact.

 

[Hoomgar]

I am going to look that over tomorrow morning before I ride Ron. Your the second one to suggest that so it warrants a look for sure.

Thx.

 

[Anonymous]

Does your starter clutch start to slip after the long pause before it gets turning? When it's really cold out and I have a poor battery in my bike I get the pause. Then it starts to chug a bit and the starter starts to slip and speed up. :? In my case it would probably start if I took the headlight out.

Steve